As someone with an electrician's ticket (non-practicing, but the exam was no joke), this is a "not-so-good" idea.
A 3kW inverter powering a fridge through extension cords (fridges/compressors can have serious inrush current). You can't just snake "yolo" cables through a house for anything drawing serious amps (say, more than 5).
I'm willing to bet zero impedance or insulation/continuity tests were done. I hope the inverter has the RCD protection included.
This "works" 99.9% of the time. Now multiply 0.1% by every person who sees this and thinks it's a clever hack.
Update: He's plugging an extension cord directly into the inverter's output terminals? A 3kW inverter at 120V can push 25A continuously (and likely no RCD in the path). That can melt a 10/15A cord. The inverter's own breaker (say, 30/40A) is there to protect the inverter, not the cord. The cord may "become" the fuse long before the breaker trips on an overload (it doesn't trip at 30A instantly, more like at 100-200A if it's equivalent to EU class B/C).
Update2: I'm against overregulation and panicing at every perceived threat, but I must say, I wouldn't mind an inspection taking a look for the sake of neighbors.
Update3: The PDF (https://cdn.shopify.com/s/files/1/0746/0415/1079/files/POW-L...) says that the AC input "maximum bypass overload current" is 40A. If he plugs the inverter into a wall outlet for charging/bypass, it will let his appliances pull 40A through a standard 15A socket. The main apartment panel will eventually trip, hopefully.
This can be done safely if you know how to compute the correct wire gauge for the distance, and don't overload the circuit. You can easily and safely run 15A via a proper-gauge extension cord from a 3kW inverter to a fridge or any number of other individual appliances at once.
Where this is potentially going to cause trouble is people who don't understand how electricity works, or that different wire gauges exist, or how many watts various appliances use. The kind of person who takes a tiny lamp extension cord and plugs a power strip into it, thinking that more sockets will provide unlimited power.
The photos in this article are scary. A 2500W power strip with a bunch of crap plugged in? Exactly the kind of scenario you don't want to see. And talking about running a fricken induction cooktop off that, along with a fridge? The photo and text imply that you have near-unlimited power.
> This can be done safely if you know how to compute the correct wire gauge for the distance, and don't overload the circuit.
Agreed, a long run adds so much impedance that during a short circuit, the breaker won't trip instantly. It will just sit there and let the fault current cook the wires.
Various jurisdictions require a fault loop impedance test for installations (and discussed one looks "fixed"). This cannot be eyeballed from a wire diameter table, must be measured.
It depends on the length of the extension cord, construction, and gauge.
10awg single conductor THHN can handle 50 amps but when it's in NM-b (house wire/romex) it's 30 amps.
Extension cords can get really hot as they often have the conductor insulation, some packaging material for support, and the outer coating. It also greatly matters if it's 10ft vs 100ft due to resistance.
I've seen extension cords that were used for ACs melt carpets
> The inverter's own breaker (say, 30/40A) is there to protect the inverter, not the cord.
I have a similar "all in one" inverter for camping, and since you seem to know what you are saying: In my setup I wired a 20A GFCI outlet to my output, and use that as my main output protection. What do you think about that?
Your receptacle (20A in your case, but regardless) is not a current limiter.
The 20A is not being "enforced" in any way and your outlet can receive, and pass on, any arbitrary current ... until something melts, that is.
You could achieve your goal by wiring in a fuse, or circuit breaker in that circuit and could probably nicely (and safely) package it up in a plastic junction box, etc.
Then again, I'm not certified for solar installations - but standard <1kV home installations and measurements. (As an anecdote, there's a specialty called 'electrical installations for hydrolysis of water' - I shall get certified in that one day just for fun.)
Buy a customer-oriented device instead, if you can. I vaguely remember there are plenty of them on the market with built-in batteries. They should have RCD/GFCI and overcurrent protection (and thermal, and BMS included) per outlet (or per bus).
If you want to stick with your current inverter, here are some thoughts from first principles:
- ground it while using, but this might be hard at a remote camping site (maybe use a grounding rod?). If it's a similar model to the one in the article, it must be grounded.
- a GFCI/RCD rated for 30mA or less with 15-20A circuit breaker (I'd suggest type-A if in EU) that matches your wiring and outlets.
There should be ready-to-go boxes that provide RCD+OC, and maybe you're already using one.
Short answer - treat it as Class I (it has a PE terminal)
Longer:
A Class I inverter/appliance relies on PE. A single insulation fault (live -> chassis) will put the chassis at line potential if PE isn’t connected.
If you run other Class-I loads (eg. fridges) downstream of a GFCI but don’t carry PE, a hot-to-chassis fault on the load won’t reliably trip anything until there’s a return path (often a person).
> A single insulation fault (live -> chassis) will put the chassis at line potential if PE isn’t connected.
As long as the other wire is not connected to ground, chassis being connected to one doesn't pose much risk.
Grounding either wire makes whole thing worse. If you ground the chassis and it's not connected to either wire it makes no difference. Once insulation on any of the wires fails and the wire connects with the chassis it becomes the neutral and ground at the same time and the other wire will shock you through ground even if you don't touch the chassis at that time.
I'm curious if GFCI would trip if you didn't have the whole thing grounded and just touched one of the wires...
I know that in normal setup GFCI detects if too little electricity goes back through neutral relative to how much goes through hot wire. Assuming nothing is grounded, would short, small leakage current when you touch one of the wires be enough to trip GFCI?
Does GFCI work both ways? If there was more current "comming back in" on the neutral than goes out on the hot would GFCI trip as well? Are the usual solutions worthless when you have just two free floating wires with potential difference between them but with no reference to ground?
Is there a code for high voltage mobile installations? It seems that EV and mobile home makers go mostly with their own solutions derived from first principles...
Well, not line-to-neutral overcurrent - which is what the person asking assumed it did.
It specifically protects against ground-path overcurrent (not ground line overcurrent - it is guarding against an undesigned path to ground, which is probably a person).
Setting 11 which default to 30A with no detail in this manual, from my experience there will be something like 2A 10A 20A 30A when you cycle the option 11 values.
> A 3kW inverter powering a fridge through extension cords (fridges/compressors can have serious inrush current). You can't just snake "yolo" cables through a house for anything drawing serious amps (say, more than 5).
Definitely on his fridge, but many newer ones are inverter drive themselves and effectively soft-start. Just 100w or whatever around the clock.
Maybe in 50 years they’ll relax my local electric code and stop requiring them to be on their own circuit. Or at least tie them with lighting so I’ll know at 8PM if the fridge has gone out for the night because the 50w of LEDs on the same branch don’t work.
The inrush curent of a fridge lasts so short it's not gonna melt anything. Things melt because of short or long running overload (relatively long, could be less than a minute, but still much longer than fridge start).
It's interesting how much 'move fast and break things lightweight hacker spirit' when it's applied to stuff you actually know about turns out to be actually just be an ethos of churning out really poorly designed systems that disregard the mountain of best practices that are very well known.
It's enough to make one suspicious of the whole attitude ...
Moving fast is fine when you’re building a prototype. Having to double check everything when you are spiking an idea slows you down too much.
But once you get something going, go back, apply all your learning (because you will have learned a lot), and do a little cleanup. Especially if it’s your own personal DIY project.
Cleanup does take some time so budget it in.
My first solar project initially looked like a mess of wires like OP’s, although confined to my workbench. But after I got it working, I calculated all wire gauges, put fuses and breakers everywhere, and put the right type of wires in the right type of conduits. As it had to transit a living space, I also made it look nice — you didn’t see a single bare wire anywhere — definitely no 2/0 cable running up a wall.
What I've discovered in nearly three decades of working in various aspects of IT: any useful prototype/proof of concept system will become a production system if you do not take specific measures from the outset to prevent that from happening.
Meanwhile - the person who knew what they were doing would design the whole thing to be safe, code compliant, and efficient from the beginning, skipping the 'making it up as I go' phase.
There is this common pattern with a certain kind of HN user of not bothering to learn about something before assuming you are way smarter than any other human who has ever lived and just doing it yourself from base principles, before inevitably finding out what everyone else already knew.
If it was just diy projects it would be one thing, but entire companies are run on this principle.
I recall a WWII sabotage manual that recommends it as a very effective sabotage technique: “let relevant authorities handle it”. Then everyone waits as the relevant authorities have being inquired through proper channels.
You can’t even hire a competent person unless you have a bit of expertise yourself. You wouldn’t know the difference.
Very well said. Reminds me of the old adage about /r/crypto “a place where people who don’t believe in financial regulations learn why financial regulations exist”
"Move fast" thing applies to lots of software because most software belongs to "fundamentally safe" class of things, along butter knives and clay sculptures. People might temporarily experience sadness if they were served a mangled butter knife or saw your sand castle collapse, but they shouldn't be hurt. You don't even have to have heard of the word "functional safety" to be safe with those. Your creation is going to be default safe and perpetually safe so let them crash and burn, is the idea.
If you were writing pieces of self driving code or were building a wooden chair for yourself to sit on, that change up things a bit. The most fundamental distinction isn't in whether it's hardware or software, but whether it's safe or not.
And it only works for things that no one truly needs. If Facebook disappeared tomorrow, we’d all be better off. If the software that runs the electrical grid disappeared, it’s a different story.
Everything you wrote is correct. And the problem the author of the original post is addressing has a very simple solution: you and your bosses should eat less and live more modestly. Your medieval cable-bolt-fitters' guild should become less exclusive and demand less money for membership. The ultimate beneficiaries of horribly expensive electricity can easily live without three ranches and two yachts. And then people won't be forced to build this cable-flipping sham.
The same applies to the rest of the construction industry in the US. If they're building houses out of cardboard and sticks, they should be paid enough to buy a cardboard steak. And house prices should be low, not like they are now.
The number of people replying to this thinking that this is novel is both amusing and surprising.
This is a DIY power bank. You can buy professionally-made ones from Bluetti, Jackery, EcoFlow, and many other companies. Including with solar panels. They've been around in some form or another for decades. Modern ones use LiFePO4 batteries, which have a solid safety profile compared to older-generation lithium batteries.
Or you can buy components and build your own, hopefully more safely than the article shows.
Go hang out on r/SolarDIY or check out Will Prowse on YouTube.
Everyone speaks with such confidence that it seems like they know what they're talking about. Then they starting talking the same way about something you're more familiar with and the illusion is quickly shattered.
similar to Elon Musk talking about pretty much everything software. I don't know why he doubled down on having played poe2. https://youtu.be/cZslebJEZbE
Its a interesting setup that indeed can bypass the red tape.... but your going to have a few other issues:
* Fire insurance or well, potential no-payout if your installation creates a fire.
* What about grounding? Does it also feed back over the invertor to your breaker panel
* How about power fusing... I doubt that he has individual fusing to his different rooms. So yea, electricity compliance is a mess. See fire insurance.
* Hanging cables with plugs hanging on them.. yep, very code compliant...
* A yes, 2500w rated distribution box with then multiple heavy loads on them.
This is one of those, interesting but big risk of burning down your own home, and neighbors in the process. It needs a ton of improvements for safety, what drives up the costs. Imagine everybody doing this, ...
> * Fire insurance or well, potential no-payout if your installation creates a fire.
This is pretty much a myth. Insurance pays out even if you cause a hazard, as long as it's not intentional (i.e., not insurance fraud). Talk to any insurance adjuster: undisclosed DIY is not enough to deny a claim.
What happens instead is that if you make a claim and the damage is due to stuff you didn't tell the insurer about, they will drop you right after they pay. Another possibility is that if they do any proactive inspections (e.g., drone fly-bys), they can decline to insure you or drop your policy.
A more substantial problem is that this page sort of oversells what they're pitching. 1.2 kW of solar power is a fraction of typical household usage. 2.4 kWh battery storage also isn't a whole lot. And yeah, it's cheaper than paying someone, but if your roof starts leaking, it's gonna cost you and you have no one to sue.
> 1.2 kW of solar power is a fraction of typical household usage.
Yes and no; it really depends on what kind of house you have, how many people live there, and (culturally?) where you live.
I have an 1800 sqft condo in San Francisco, and a 3.6-4.0kW solar system would be what I'd end up installing if I were to do it the "normal" route with an installer and all the "red tape". Yes, that's obviously 3+ times the 1.2kW demonstrated here, but even a system like that would be useful for me to reduce my electricity costs (especially given where I live).
I know people with more modest electricity needs than I have. I also know people who have 16kW of solar on their roof and that still isn't enough to avoid pulling power from the grid sometimes. So: yes and no; it depends.
I never planned & priced out battery storage, but, sure, 2.4kWh would be pretty low for my needs, but it would still be useful.
It's just weird that the article title includes the phrase "energy independence", when the author admits that they still pull more than half their usage from the grid.
my wife and I managed to get to an average load of 100 Watts (2.4 kwh per day) for months at a time when we lived in San Diego, albeit with no a/c and gas heating/cooking/hot water. Modern appliances generally don't need much.
I think this could be considered intentional, because in most countries, connecting this inverter to anything (source, sink) would require certification (+tests), as it doesn't have standard electrical outlets (it varies from country to country, but in the countries I've seen, either certification is required or connecting wall/ceiling lamps is exempted from this, but verification must be done afterward).
I read about this often whenever I'm looking at guidance for one of my hobbies, and often people are dealing with it in their garage. Some jurisdictions are more okay with DIYing than others, but it's all too common that someone is taking 240V, 30A and going to an enclosure that they built to get 3+ HP/2+ kW at 240 or 480V, three phase.
The common refrain is that your insurance will deny your claim.
The response that people get when they call their insurance is "you pay us to cover you even when you do the wrong thing". Just like how your auto insurance covers you when you rear-end someone while drunk as hell, when you drape way too many lights on your crispy dead Christmas tree, or when you fall asleep and light your drapes on fire with a cigarette.
Intent is when you set out to cause an accident.
(You should probably read your actual insurance policies before considering my not-a-lawyer American-centric comments.)
I think nobody mentioned about insurance fraud. There is a difference between a accidental mistake, not knowing what your doing, and knowing that your bypassing regulation willingly.
This type of installation needs to be reported to the insurance company. Remember, coverage applies to the state of your vehicle/home/property. If you DIY your own power source, the insurance company when informed about it, may drop your coverage.
If they know about the installation, its much harder for them to deny a claim. But a hidden installation like that, is a factor in claim denying.
And we are kind of ignoring the whole "your not just putting yourself at risk but also all the other people" issue".
It really couldn't. "Intentional" as it, you destroyed your property on purpose. Not "you were a dumbass and caused damage", not "you didn't apply for a permit and caused damage". Insurance covers stuff like that, because otherwise, a good half of claims could be getting denied. Basically all kitchen fires are "dumbass moments", for example.
The third option is hiring someone to certify it, usually requires submitting the plans beforehand. Afaik up to 800w you can do a lot DIY here but upwards you needs certification.
> What happens instead is that if you make a claim and the damage is by some stuff you didn't tell the insurer about, they will drop you right after they pay. Another possibility is that if they do any proactive inspections (e.g., drone fly-bys), they can decline to insure you or drop your policy.
Anecdata disagrees; insurance will reject payouts aggressively. I know someone whose house "coincidentally" burned down while his neighbor had a bonfire, and his insurance fought him for months.
Insurance will fight, but they have not the final decission. Here in Spain they were denying thousands of payouts for car accidents if the car was overdue in their ITV (yearly state mandated revision). But the judge had different thoughts, and they had to pay.
Big difference between refusing payout because of expired ITV and this installation.
If you alter your car its electrical harnas wiring and this creates a short somewhere, resulting in your car burning down ... that is a whole difference situation then missing a mandatory inspection. One is deliberate alteration of a vehicle and one is a inspection of condition.
Most insurances have a lot of protective language (for the insurance company), that often comes down to "everything needs to be code compliant/manufacture original/...".
The bigger the damage, the bigger the chance that insurance companies will fight you. If the above mentioned installation creates a small kitchen fire that cost a few 1000 bucks, they probably are not going to fight it.
But what happens if the above mentioned installation burns down the building, kills 5 people... Do not forget that the other neighbors / building owner's insurance companies, will go after your insurance if you are identified as the cause.
The issue is that if you go to court, and a fire comes from your apartment is from a accident, or a state like this, courts are willing to side with the victim party. But if a fire is the result of your own "tampering" with devices, electrical, etc, there is a very, VERY high chance that the court will side with the insurance provider. Insurances are not blank "do whatever you want, you get coverage" type of deals.
By assumption this is a rental. If I were the landlord and saw this I would be worried, but the tenant doesn't have all that much to worry about beyond their own stuff. And dying I guess
So this is terrifying for all the reasons mentioned below, but the _core_ setup where it is not connected to the utility and acts (basically) like a solar powered UPS is really attractive to me.
All the commercial solar setups out there spend a lot of effort pushing power back to the grid, when all I really want is this configuration to all my outlets.
Does anyone know of a setup like this? Basically a power bank that charges primarily from solar, secondarily from the grid, and provides my normal panel with power through an inverter (or panels/inverters, I actually expect). Feeding back to the grid seems more trouble than its worth...
You want what is called a AC coupled system. Basically, you put something like a charger/inverter/mppt just upstream of your breaker box so that downstream of your breaker box you don't need to change anything. You can find solutions that are a all-in-one like this one [1]. This particular product outputs up to 5kw on a single phase to your breaker box. So if you need more power you either wire 3 of them in a 3-phase system, or in parallel on the same single phase.
Finally, from the settings you can stop the unit(s) from sending power back on the grid so that you don't have to deal with that hurdle of changing the meter, permits, ... .
I linked an example wiring here [2]. I don't work for Victron, but I am just an happy customer :)
They are certified. In the sense that if the grid goes down it won't send electricity into it regardless of the settings you have. If you set it up to avoid feeding back energy it is completely transparent from an utility operator perspective. This is at least what the electrician that signed off my installation said and it works for the EU grid. Not sure about US or other parts of the world.
Yes. As someone else noted, there's an excellent community on reddit for /r/SolarDIY with a lot of people who do this. The standard setup is to buy an offgrid inverter that will take shore power. Size your unit to handle your entire house. Throw it _behind_ your electrical panel so that it feeds all of your house. You're basically building a DIY whole-house battery backup + solar.
The EG4 gear is really popular for this. Don't go quite as cheap on the inverter or batteries as the OP did - you want something reliable, and for doing whole-house you want rackable batteries that you can easily parallelize and that have controllers you can talk to.
This isn't exactly what you want, but you could get the same kind of breaker interlock used for traditional generators and use that for the solar inverter. The downside is that you can't blend grid and battery power at the same time, but this may not actually be a problem in a practically sized setup where solar is the primary.
The issue is cutting off your inverter from your grid without also cutting off your outlets from the grid. The ways I've seen to do this are to either put some clamp meters on your grid connection and configure your inverter to a "zero export" mode that'll scale depending on your current usage. Not sure about the legality of that; I'm sure it depends on your locality.
Or to put your outlets on a subpanel with the inverter controlling the feed to that subpanel. Maybe with a 2nd lockout connection to the main panel so you can do maintenance on the inverter without having no power.
Our inverter lets you set it so that it doesn't do any grid export, and otherwise sits between the grid and the normal main breaker panel.
If you do this, I'd highly recommend that you put a transfer switch in place that lets you connect the grid back to the breaker panel with the flip of a lever, and cut the inverter out of the loop. That way, if the inverter ever goes down for whatever reason, you can cut it out and do maintenance on it without any "why is the power still not on".
I don't live in the states, but I have a "home energy gateway" which is to say in human: a big switch that isolates my house, solar and batteries from the grid.
I think the generic term is "islanding" (could be wrong)
The downside of my system is that it takes a non-trivial amount of time to switch to island mode, which means lots of computer things reset during the process.
So you don't get 100% uptime, but you are able to carry on when there is an outage.
Ecoflow will sell you rather respectable boxes that contain a battery, and MPPT charge circuit, and an inverter-charger all in one. And those boxes have real BMSes inside, too, unlike this sketchy setup.
Like, yeah, there's some sketchy stuff with connecting those loads to this over extension cords snaked all around the house, but this setup is basically what you're asking for.
GP is asking for the non sketchy way, that lets them use their outlets etc. Which is not trivial because if you still want to be connected to the grid you need to make sure you don't feed power back into it when it's not expected, like during a power outage.
Doing something like hooking it up with a suicide cord is asking for absolute shitheaps of trouble. If you are feeding your outlets, you run the very real risk of backfeeding the grid and electrocuting an unfortunate lineman when the power goes out. You've basically got to get the utility to do this for you, as you need a real transfer switch and their explict buy in, as the only safe and correct way to do this is on the utility side of the distribution box. Doing that basically means getting setup to feed back to the grid as far as I've seen anyways.
> Does anyone know of a setup like this? Basically a power bank that charges primarily from solar, secondarily from the grid, and provides my normal panel with power through an inverter (or panels/inverters, I actually expect). Feeding back to the grid seems more trouble than its worth...
You need to look for off-grid inverters. They are now really popular in Ukraine because of constant power outages.
The state-of-the-art are inverters that can seamlessly blend off-grid and grid-tied functionality, so you can both export your energy to the grid (if you have a surplus) and smoothly fall back to the battery power if the grid is lost. And they can even control standby generators in case the battery is gets low and there's no grid power.
What blows my mind, is that you can even parallel them together to get more power if needed. They even handle the grid synchronization without any voltage spikes.
Firefox detected a potential security threat and did not continue to sunboxlabs.com. If you visit this site, attackers could try to steal information like your passwords, emails, or credit card details."
Balcony solar kits are popular in Germany which are a more legit version of this.
The main thing I would be nervous about is the panels are claimed to be "rated for 120km/h winds". Presumably thats if they are bolted down? Just laying them down loose on the roof seems like a bad idea.
Yeah I came looking for this comment. I’m in Florida, USA where high winds are the norm. A big shingle sitting there not tied down would flip real quick.
On the one hand I like this... on the other hand, the electrician's assistant in me that tries to be as NEC-compliant as possible is absolutely cringing at a few of the pictures on there.
With that said... a few hundred more dollars, and this could be a proper setup with a proper load centre, breakers, and so on. Simply replace a lot of your home's existing wiring.
The article author claimed they got their landlord's permission first, so I doubt they'll be taking it down when the landlord comes over. They'll just take it down when they move out.
Also... I lived in rented apartments for more than 15 years, and the only time a landlord entered my unit was one time when I explicitly asked her to (there was a water leak, and I was about to leave town and wouldn't be around to let the workers in to fix it). Is this a normal thing? Are landlords constantly visiting their tenants?
I'm a landlord for a property in the UK, I have an agent who does this kind of thing for me as I don't know the regulations and also I don't live in the country, but yes property visits are normal… at least in the UK.
They don't do smoke alarm inspections? AC filter replacements? I've never lived anywhere where they didn't come in multiple times a year just for those things.
Depends. Here the landlord is responsible for providing working smoke detectors at move-in time but the tenant is responsible for periodically testing them and replacing batteries.
It mostly boils down to how nosey your landlord is. If they are constantly stopping by to inspect things or change filters more than a couple times a year it’s probably an excuse to see what you’re up to.
> It mostly boils down to how nosey your landlord is. If they are constantly stopping by to inspect things or change filters more than a couple times a year it’s probably an excuse to see what you’re up to.
Really depends who manages your building. We had the most issue with the landlord who also manages the building. Like tons of inviting themselves over, very nosy and intrusive.
When we moved out and the final inspection date. We cleaned everywhere that is logical ... ground, windows, bathroom, sinks, tubs, glass, kitchen, drawers, .. you name it.
They then demanded on the move out date, that we clean above the doors, i mean, the flat part above the internal doors, outside some small toilet window that had not been cleaned in 10+ years. We even told them, why is this on us when clearly you did not do so with the previous tenant (we only lived there 1 year). No no, it became that dirty in that one year. Yeaaa, bull... May have something to do that we are "foreigners".
Plenty more crazy stuff... locations where you do not even think about like ducting. Imagine when you read this, look around, and imagine the spots where you never think about cleaning because its kind of crazy. They really looked for every excuse to deny our deposit (did not work). We had plenty of pictures from our move in date, and used them against the landlord.
Where as the building we are in now, beyond the move in date, not a single inspection or anything like that. Sure, a few times that they came to do work, like replacing the smoke detectors, or painting, but those are all 3th parties.
Learned the lesson to never rent from somebody who is the landlord and manages the property at the same time. Too much trouble.
We get 2-3 power outages every year where I live. Mainly due to trees with ice/snow/wind. My solution was to buy three power banks. A 500Wh, and a couple of 300Wh. I have a pluggable camp fridge too and a gas fireplace. So one battery powers the fan in the fireplace, another for the cooler to keep the food from spoiling. And the third one for a couple of the lights (with LED bulbs). Works great and we can handle an outage that lasts about 4-5 days. Also we got 4 of these rechargeable lanterns for lights around the house. I just keep the batteries and lanterns charged. Really easy and my investment is about $1000.
Do you mean 500Wh rather than 500kWh? 500 kWh would be around 10 EVs worth, and looks like it costs around 700k [0], but 500Wh seems to be a common size for portable power stations [1]
I think you're off by a couple of orders of magnitude... 500Wh and 300Wh maybe? Or 5kWh and 3kWh if you got a very great deal? Your investment would be orders of magnitude more than $1000 for around a total of 1MWh!
Suppose I own my house and don't feel like running a new set of wires thru my house, so I'm comfortable separating the panel into a downstream solar-capable subpanel and a real battery stack, but want a similarly thrifty and red-tape-free setup (which never backfeeds the grid). What other pieces of equipment could I substitute?
You can pretty easily setup a subpanel with a feed-in outlet and an interlock so you only have the feed-in or the grid breaker closed, but not both. Something like this [1], but you need to shop to match your panel.
That's thrifty; changing a panel/building a subpanel probably needs a permit, but shouldn't need utility approval. A transfer switch is an option too, but not so thrifty, and if you an automatic transfer switch, they usually work the other way (use grid if available, fail to local generation), but you could probably make it work.
I've been living in a rental for a while, and I have a woodshop in the garage. I've been really wanting to have a 220V outlet to run some bigger power tools, but if figured doing that would require hiring an electrician to come do some work in the breaker box. This has me curious if I can do something like this just to power some stuff in my garage, and also potentially charge an electric car.
Hiring an electrician is going to be cheaper probably, depending on the length of the run and how annoying the location is (and if your panel has enough capacity to spare). Unless your landlord is an asshole they probably won't care, in my experience, as long as you get a qualified person to do it. You're basically improving their place so it's not a hard thing to get approved.
Btw for the second part, you _can_ charge electric cars over just normal 15amp circuits you already have. It's just slow, so you'd only want to do it for nightly charging and it may depend on your commuting range if it'll work out or not.
You could get something like an eco flow battery, charge it on your 120v service and then use its inverter to run your intermittent 240v loads. IIRC their models support being in charge and invert mode simultaneously, so you wouldn't have to swap plugs or change settings throughout the day.
The Delta Pro series is capable of running a 3 ton AC condensing unit, so if your tools are less demanding than this it should work out.
Does that mean all of your appliances, which should supposedly each run on a separate line, now are all plugged on a big single-line powerstrip? Sure, this single-line is only used when battery and sun are out, but when it happens...
Since the inverter is 3 kW, and the battery is 2.5 kWh, you don't run many appliances off it. Hopefully it shifts your air cooler's peak of consumption away from the most expensive evening hours. You can probably cook at daytime directly from solar power.
When the battery is depleted, you, I suppose, just pull the plug from a battery-fed power strip, and push it into a regular socket.
I would put 3x the battery capacity, which would add about $500-600 to the cost.
What would change if you wanted to do something like this but for an EV? You already have a large battery, you can make decisions like "I need to be full for my road trip tomorrow, so fill from the grid", but you can just trickle charge from some fixed solar panels throughout the day most of the time. I think amperage can even be negotiated via the standard EV charge cable.
Ugh, these two-lead LFP batteries without any sort of BMS communication are fairly nasty devices. The inverter/charger does not know the maximum safe charge or discharge current, the cell temperature, the cell balance state, or really anything else except the voltage. If the actual BMS in the battery (assuming there’s one in there at all) wants the charger to slow down, it has no way to tell it to do so. The charger has no way to know what it needs to do to get the cell balancing circuit (if any) to work. And the BMS (again, assuming it exists) can’t even communicate the state of charge to the inverter/charger.
At least this particular setup uses a somewhat dignified 24-ish volt setup instead of the usual awful “12V” that is often seen in this genre of battery.
BMS <-> "solar inverter" communication is not required. All LFP batteries that aren't raw cells have a BMS, which have over/under voltage protection. A bad charger isn't going to do anything.
There's also nothing wrong with 12V setups (see all the RVs that are out there).
> BMS <-> "solar inverter" communication is not required.
It’s “not required” in the sense that it works. Poorly. Have you contemplated how balancing between paralleled “12V” LFP packs works? LFP has a voltage vs SoC curve that is very unpleasantly flat for purposes of cell balancing without intelligence, and almost no intelligence is available in these arrangements.
> Theres nothing wrong with 12V setups (see all the RVs that are out there).
There is so much wrong with them that it’s hard to even know where to start.
Let’s suppose you have an RV-like setup that is designed to power one single 15A 120V receptacle. That’s 1800W, which is pretty small by the standards of modern inverters. It’s also 150A at 12V. Want decent efficiency? That means you want to lose less than, say, 2V on the wires, so you need to carry those 150A over a round trip resistance below 13.3mOhm. If you use the ABYC ampacity table, that’s 2AWG or larger wire. Fortunately 2AWG will carry 150A a respectable distance without excessive voltage drop.
Now, 150A is a lot of current. 150A will make massive sparks, light things on fire, and weld sizable pieces of metal even if 12V is unlikely to electrocute you. And you’re feeding that wire or bus in multiple places (because you may have multiple batteries and a beefy charger), so you remember to put giant 150A fuses or breakers at all the feed locations, right?
But wait, 12V needs below 0.08 ohms to produce 150A. Want to comfortably blow a 150A fuse? You need well below 0.08 ohms total resistance in the entire circuit, including the fault. If you have a high resistance fault (and “high” could be 70 mOhms!), you will never blow the fuse and you can produce literally kilowatts of heat. Crispy! (Your house likely has circuits bigger than 150A, but it’s at a voltage that can much more easily trip the breaker, and in civilized countries there will be some sort of RCD as well.)
Oh, and that 2AWG cable is expensive, hard to bend, and requires actual skill to terminate well. And modern systems often target powers well above 1800W.
At least in a car, the high current portion of the 12V system is made and tested in a factory. And it still makes amazing showers of sparks if anyone messes up a jumper cable. There’s a reason that car makers want to move away from it.
Plastic distribution boxes are actually really common in residential installations in Europe, Australia etc. The UK standard has changed to metal now for fire risk but plastic is common around the world.
It’s more the grounding issues and lack of a properly sized circuit breaker to protect the extension cords etc.
I think plenty of folks just have a vague understanding of electrical codes and say stuff like that to impress others.
Generally speaking, you're just not supposed to do permanent electrical wiring with extension cords and power strips, especially not for stuff that goes into or through walls. This has nothing to do with plastic - you have plenty of plastic in electrical boxes, outlets, PVC conduit, etc. Cable insulation is plastic too.
The electrical code doesn't want you to put extension cords in the wall mostly to make sure that the connections can't come apart, that the comparatively softer and more delicate wires aren't easily crushed or abraded, and so on.
This project definitely isn't done the way you should do it if you had a real budget dedicated to it. Is it a death trap? Meh, I've seen far worse extension-cord contraptions in US homes.
Two things come to mind: 1) if any arcing occurs, a metal enclosure will shunt to ground and (hopefully) trip a breaker; 2) in the event of an overload, plastic melts which might result in a fire.
The fact that this is the most appealing option is an indication that our electrical system, both equipment and code, are failing to address people’s needs. If you get a quote for a hybrid (on and off grid) system, they’re absolutely unaffordable.
The more common term for the unit is a solar inverter or off-grid inverter.
I run a few of these on an off grid property and they're totally fine. I would be wary of a cheap no-name brands. I'm also be wary of running extension cords all over the place.
If you have the space (a mechanical closet?). I'd suggest getting a separate inverter and charge controller. These all-in-one units have fairly high idle inverter draw.
I remember seeing this on HN a couple years back. At the time, this made financial “sense”. But nowadays, you can get an all in one refurbished for sub $700. This way, it’s truly portable and all you need to worry about is getting the solar panel power to your battery generator.
This is hard to share in a lasting way. The post I want to share is just the main page which could change and loose context after some amount of time. I recommend a subpage for articles to help long term sharing.
The US really needs to get onboard with "balcony solar" or "plug-in solar."
> small solar panels that can be easily installed on balconies and plugged directly into a standard wall outlet, allowing users to generate their own electricity.
I believe this is common in Europe. They’ve figured out some way to make it safe for the grid and line workers.
I have been thinking lately about what it might take to run a small house entirely off grid. My thought was that if you could build a separate battery shed that is away from everything and then fill it with like 100 kWh of batteries charged by a 30 kW solar array, then you could presumably run power from the battery shed to your house as if it was a normal utility hookup. But then again I have no clue if a town zoning office or building inspector would have a fit over a setup like that.
None of the equipment in this article does that. It takes power from the grid the way any appliance does; it optionally charges by solar; and it provides power the same way a UPS does, using ordinary female power sockets.
But there are devices out there that do feed power over the exposed prongs of a male plug. They're called "suicide cords" for good reason.
Ah. I saw a whole thing about solar panels for balconies that did exactly this. I skimmed the article and thought I saw the same idea. I missed that it’s just charging a battery.
Why? It's just a battery charger. They are basic-ass components and there are a zillion UL-listed lithium chargers that are perfectly safe and in common use.
There a many problems with this article, but the fact that it includes a battery charger is not one of them.
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> The secret sauce is that the sunbox is usually off-grid and never pushes power back into the grid. The only reason it's connected to the wall at all is that if it runs out of power it can pull energy from the wall.
Ideally we all could push power back to the grid & that ought not be hard, but in point of fact that can be a huge barrier.
It's not capable of generating as much power, but I love what Zoltux and many others are doing: attaching current sensors to the main breaker box, and using that as feedback to make sure the solar is never generating so much power that it pushes to the grid. Pretty mild 800w power on the Zoltux. https://zoltux.com/
The existing DJI Power 2000 added this capability with a recent software update, if you have a compatible energy meter! Can accept up to 1800 watts of solar power. I'm not sure if there's any difference between this kind of setup and a european balcony solar install? https://www.renewableenergymagazine.com/pv_solar/dji-power-2...
They took this down so quickly. Bad examples are great to learn from. I don't get all the hate, and it just seems like a bunch of bullies found out and put the red tape on it. Don't you think "burning a house down" is a vast over exaggeration? I wouldn't trust any professionals using such intimidating tactics.
Do they not teach "the boy who cried wolf"? It doesn't get worse than claiming this stuff will burn someone's house down around with everyone around them.
"Just" is doing a lot of work there. Maybe the idea is reasonable, but the setup as-is is not safe, and there's nothing in the article that would tell you that, or tell you what you need to add to it to make it safe. Many people might read the article, think that it's all safe (because they don't have the knowledge required to properly evaluated it), and then burn their houses down.
Not saying this is the most unsafe thing I've ever seen or heard of, but we have electrical codes for a reason... because buildings have burned down and people have died.
It falls into that "soft bigotry of low expectations" zone. There are intro articles and advanced articles; the advanced ones don't need to spend the first 1/3 of the volume talking about safety.
I live in a climate with cold winters though, so I hate to invest in something like this and not be able to use it for a significant part of the year. I guess I could put a small pellet or wood stove in it..
If you don't need/can't use the grid backup you could probably get away with a cheap-ish Ecoflow/anker/etc battery with some solar plugged in and save a few hundred bucks
This is like a guerrilla solar recipe from the anarchist’s cookbook.
The author doesn’t explicitly dissuade people from plugging in another multipoint/powerstrip/plugstrip into the end of the extension cable you’ve run into the other room. So I will. Don’t do that. There are plenty of low gauge, cheap extension cables out there which will degrade fast in this setup, and may cause a fire.
Also, if your landlord is okay with seeing this setup they probably don’t have insurance they’re worrying about, and are simply making sure you’re not actively destroying the property (rather than potentially destroying it with the fire hazard).
Good news! I looked on Amazon and I found one that goes all the way up to 18! It also says ‘fully copper coated’ so you know it’s good. (/s, please never do this)
I often downvote posts like this, on the grounds that excessive safety nannyism doesn't belong on a site called Hacker News... but having seen what they call a "2500W power distribution strip," yeah... have an upvote or three.
Assuming the linked products are the products in the picture, the strip is a product from Southwire that is claimed to be rated for 20 amps / 2500W and southwire is an established and known brand. It is listed as being for “temporary” installations and I’m not sure I’d want to run that load through it all the time, but it’s probably not that bad.
It's 120V. Pushing 20A continuous through that kind of wiring is less than ideal.
First of all, let's assume less than ideal conditions so base our calculations on 115V. 2,500 watts is going to be 21.7 amps; assuming a continuous load (which is pretty reasonable for a whole house) is going to need a breaker and wiring that's rated for 125% of that, or 27.2A.
That means the supply needs to be #10 wiring and should be fitted with a 30A breaker at the disconnect. A temporary power tap is not a suitable disconnect. And I highly doubt it's got 10 gauge wiring.
Dont fuck with electricity. I think the intuitions people have are based on home installations with RCDs, fuses and earthing and proper cabling before it gets to that socket. You then plug in a distribution to draw 100w for your devices and maybe the occasional 2kw for the vacuum cleaner for 5 minutes if too lazy to use another socket. Yoy not running full house load through it all day.
As someone with an electrician's ticket (non-practicing, but the exam was no joke), this is a "not-so-good" idea.
A 3kW inverter powering a fridge through extension cords (fridges/compressors can have serious inrush current). You can't just snake "yolo" cables through a house for anything drawing serious amps (say, more than 5).
I'm willing to bet zero impedance or insulation/continuity tests were done. I hope the inverter has the RCD protection included.
This "works" 99.9% of the time. Now multiply 0.1% by every person who sees this and thinks it's a clever hack.
Update: He's plugging an extension cord directly into the inverter's output terminals? A 3kW inverter at 120V can push 25A continuously (and likely no RCD in the path). That can melt a 10/15A cord. The inverter's own breaker (say, 30/40A) is there to protect the inverter, not the cord. The cord may "become" the fuse long before the breaker trips on an overload (it doesn't trip at 30A instantly, more like at 100-200A if it's equivalent to EU class B/C).
Update2: I'm against overregulation and panicing at every perceived threat, but I must say, I wouldn't mind an inspection taking a look for the sake of neighbors.
Update3: The PDF (https://cdn.shopify.com/s/files/1/0746/0415/1079/files/POW-L...) says that the AC input "maximum bypass overload current" is 40A. If he plugs the inverter into a wall outlet for charging/bypass, it will let his appliances pull 40A through a standard 15A socket. The main apartment panel will eventually trip, hopefully.
This can be done safely if you know how to compute the correct wire gauge for the distance, and don't overload the circuit. You can easily and safely run 15A via a proper-gauge extension cord from a 3kW inverter to a fridge or any number of other individual appliances at once.
Where this is potentially going to cause trouble is people who don't understand how electricity works, or that different wire gauges exist, or how many watts various appliances use. The kind of person who takes a tiny lamp extension cord and plugs a power strip into it, thinking that more sockets will provide unlimited power.
The photos in this article are scary. A 2500W power strip with a bunch of crap plugged in? Exactly the kind of scenario you don't want to see. And talking about running a fricken induction cooktop off that, along with a fridge? The photo and text imply that you have near-unlimited power.
> This can be done safely if you know how to compute the correct wire gauge for the distance, and don't overload the circuit.
Agreed, a long run adds so much impedance that during a short circuit, the breaker won't trip instantly. It will just sit there and let the fault current cook the wires.
Various jurisdictions require a fault loop impedance test for installations (and discussed one looks "fixed"). This cannot be eyeballed from a wire diameter table, must be measured.
It depends on the length of the extension cord, construction, and gauge.
10awg single conductor THHN can handle 50 amps but when it's in NM-b (house wire/romex) it's 30 amps.
Extension cords can get really hot as they often have the conductor insulation, some packaging material for support, and the outer coating. It also greatly matters if it's 10ft vs 100ft due to resistance.
I've seen extension cords that were used for ACs melt carpets
> The inverter's own breaker (say, 30/40A) is there to protect the inverter, not the cord.
I have a similar "all in one" inverter for camping, and since you seem to know what you are saying: In my setup I wired a 20A GFCI outlet to my output, and use that as my main output protection. What do you think about that?
PS: op took down their page. archive link is here: https://web.archive.org/web/20251005022124/https://sunboxlab...
Your receptacle (20A in your case, but regardless) is not a current limiter.
The 20A is not being "enforced" in any way and your outlet can receive, and pass on, any arbitrary current ... until something melts, that is.
You could achieve your goal by wiring in a fuse, or circuit breaker in that circuit and could probably nicely (and safely) package it up in a plastic junction box, etc.
Then again, I'm not certified for solar installations - but standard <1kV home installations and measurements. (As an anecdote, there's a specialty called 'electrical installations for hydrolysis of water' - I shall get certified in that one day just for fun.)
Buy a customer-oriented device instead, if you can. I vaguely remember there are plenty of them on the market with built-in batteries. They should have RCD/GFCI and overcurrent protection (and thermal, and BMS included) per outlet (or per bus).
If you want to stick with your current inverter, here are some thoughts from first principles:
- ground it while using, but this might be hard at a remote camping site (maybe use a grounding rod?). If it's a similar model to the one in the article, it must be grounded.
- a GFCI/RCD rated for 30mA or less with 15-20A circuit breaker (I'd suggest type-A if in EU) that matches your wiring and outlets.
There should be ready-to-go boxes that provide RCD+OC, and maybe you're already using one.
> ground it while using, but this might be hard at a remote camping site (maybe use a grounding rod?).
What's the point of grounding it? So you can get shocked by touching one wire instead of two?
Short answer - treat it as Class I (it has a PE terminal)
Longer: A Class I inverter/appliance relies on PE. A single insulation fault (live -> chassis) will put the chassis at line potential if PE isn’t connected.
If you run other Class-I loads (eg. fridges) downstream of a GFCI but don’t carry PE, a hot-to-chassis fault on the load won’t reliably trip anything until there’s a return path (often a person).
> A single insulation fault (live -> chassis) will put the chassis at line potential if PE isn’t connected.
As long as the other wire is not connected to ground, chassis being connected to one doesn't pose much risk.
Grounding either wire makes whole thing worse. If you ground the chassis and it's not connected to either wire it makes no difference. Once insulation on any of the wires fails and the wire connects with the chassis it becomes the neutral and ground at the same time and the other wire will shock you through ground even if you don't touch the chassis at that time.
I'm curious if GFCI would trip if you didn't have the whole thing grounded and just touched one of the wires...
I know that in normal setup GFCI detects if too little electricity goes back through neutral relative to how much goes through hot wire. Assuming nothing is grounded, would short, small leakage current when you touch one of the wires be enough to trip GFCI?
Does GFCI work both ways? If there was more current "comming back in" on the neutral than goes out on the hot would GFCI trip as well? Are the usual solutions worthless when you have just two free floating wires with potential difference between them but with no reference to ground?
Is there a code for high voltage mobile installations? It seems that EV and mobile home makers go mostly with their own solutions derived from first principles...
Not the person you are replying to, but a GFCI does not protect against overcurrent.
Well, not line-to-neutral overcurrent - which is what the person asking assumed it did.
It specifically protects against ground-path overcurrent (not ground line overcurrent - it is guarding against an undesigned path to ground, which is probably a person).
thanks, I'll put a breaker in-line.
This kind of inverter usually have a setting to limit the current they can draw from the grid.
From the manual of this particular model:
https://cdn-files.myshopline.com/file/store/1675916196960/AN...
Setting 11 which default to 30A with no detail in this manual, from my experience there will be something like 2A 10A 20A 30A when you cycle the option 11 values.
> A 3kW inverter powering a fridge through extension cords (fridges/compressors can have serious inrush current). You can't just snake "yolo" cables through a house for anything drawing serious amps (say, more than 5).
Definitely on his fridge, but many newer ones are inverter drive themselves and effectively soft-start. Just 100w or whatever around the clock.
Maybe in 50 years they’ll relax my local electric code and stop requiring them to be on their own circuit. Or at least tie them with lighting so I’ll know at 8PM if the fridge has gone out for the night because the 50w of LEDs on the same branch don’t work.
The inrush curent of a fridge lasts so short it's not gonna melt anything. Things melt because of short or long running overload (relatively long, could be less than a minute, but still much longer than fridge start).
The duration is not the issue; gross energy size is the issue. The inrush is probably longer than a lightning strike...
Unless there's a fault with the fridge of some sort.
It's interesting how much 'move fast and break things lightweight hacker spirit' when it's applied to stuff you actually know about turns out to be actually just be an ethos of churning out really poorly designed systems that disregard the mountain of best practices that are very well known.
It's enough to make one suspicious of the whole attitude ...
Moving fast is fine when you’re building a prototype. Having to double check everything when you are spiking an idea slows you down too much.
But once you get something going, go back, apply all your learning (because you will have learned a lot), and do a little cleanup. Especially if it’s your own personal DIY project.
Cleanup does take some time so budget it in.
My first solar project initially looked like a mess of wires like OP’s, although confined to my workbench. But after I got it working, I calculated all wire gauges, put fuses and breakers everywhere, and put the right type of wires in the right type of conduits. As it had to transit a living space, I also made it look nice — you didn’t see a single bare wire anywhere — definitely no 2/0 cable running up a wall.
You could also look at it as craftsmanship.
What I've discovered in nearly three decades of working in various aspects of IT: any useful prototype/proof of concept system will become a production system if you do not take specific measures from the outset to prevent that from happening.
Meanwhile - the person who knew what they were doing would design the whole thing to be safe, code compliant, and efficient from the beginning, skipping the 'making it up as I go' phase.
There is this common pattern with a certain kind of HN user of not bothering to learn about something before assuming you are way smarter than any other human who has ever lived and just doing it yourself from base principles, before inevitably finding out what everyone else already knew.
If it was just diy projects it would be one thing, but entire companies are run on this principle.
I recall a WWII sabotage manual that recommends it as a very effective sabotage technique: “let relevant authorities handle it”. Then everyone waits as the relevant authorities have being inquired through proper channels.
You can’t even hire a competent person unless you have a bit of expertise yourself. You wouldn’t know the difference.
There is some productive Middle Way here.
CIA simple sabotage manual - insist works are completed through proper channels and where possible referred to relevant committee.
Huh? You can absolutely hire a competent solar system designer quite easily as a layperson.
Very well said. Reminds me of the old adage about /r/crypto “a place where people who don’t believe in financial regulations learn why financial regulations exist”
A place where you can watch people slowly reinvent the existing financial system.
"Move fast" thing applies to lots of software because most software belongs to "fundamentally safe" class of things, along butter knives and clay sculptures. People might temporarily experience sadness if they were served a mangled butter knife or saw your sand castle collapse, but they shouldn't be hurt. You don't even have to have heard of the word "functional safety" to be safe with those. Your creation is going to be default safe and perpetually safe so let them crash and burn, is the idea.
If you were writing pieces of self driving code or were building a wooden chair for yourself to sit on, that change up things a bit. The most fundamental distinction isn't in whether it's hardware or software, but whether it's safe or not.
"but whether its failure would be dangerous or not."
It's also complete bullshit if you know anything about writing software.
move fast and break things was always a software mantra.
And it only works for things that no one truly needs. If Facebook disappeared tomorrow, we’d all be better off. If the software that runs the electrical grid disappeared, it’s a different story.
There is a reason we still run COBOL systems, and it is nothing but the opposite of that mantra.
Move fast and break things has only been a VC-backed company thing.
Everything you wrote is correct. And the problem the author of the original post is addressing has a very simple solution: you and your bosses should eat less and live more modestly. Your medieval cable-bolt-fitters' guild should become less exclusive and demand less money for membership. The ultimate beneficiaries of horribly expensive electricity can easily live without three ranches and two yachts. And then people won't be forced to build this cable-flipping sham.
The same applies to the rest of the construction industry in the US. If they're building houses out of cardboard and sticks, they should be paid enough to buy a cardboard steak. And house prices should be low, not like they are now.
The number of people replying to this thinking that this is novel is both amusing and surprising.
This is a DIY power bank. You can buy professionally-made ones from Bluetti, Jackery, EcoFlow, and many other companies. Including with solar panels. They've been around in some form or another for decades. Modern ones use LiFePO4 batteries, which have a solid safety profile compared to older-generation lithium batteries.
Or you can buy components and build your own, hopefully more safely than the article shows.
Go hang out on r/SolarDIY or check out Will Prowse on YouTube.
Reading HN regarding tech makes me think I'm stupid. Then I see HN discuss hands on real world things, and I start wondering if actually HN is stupid.
Reddit has the same issue.
Everyone speaks with such confidence that it seems like they know what they're talking about. Then they starting talking the same way about something you're more familiar with and the illusion is quickly shattered.
similar to Elon Musk talking about pretty much everything software. I don't know why he doubled down on having played poe2. https://youtu.be/cZslebJEZbE
Never read a thread on HN about a subject you have deep knowledge in.
https://en.wikipedia.org/wiki/Gell-Mann_amnesia_effect
Its a interesting setup that indeed can bypass the red tape.... but your going to have a few other issues:
* Fire insurance or well, potential no-payout if your installation creates a fire.
* What about grounding? Does it also feed back over the invertor to your breaker panel
* How about power fusing... I doubt that he has individual fusing to his different rooms. So yea, electricity compliance is a mess. See fire insurance.
* Hanging cables with plugs hanging on them.. yep, very code compliant...
* A yes, 2500w rated distribution box with then multiple heavy loads on them.
This is one of those, interesting but big risk of burning down your own home, and neighbors in the process. It needs a ton of improvements for safety, what drives up the costs. Imagine everybody doing this, ...
> * Fire insurance or well, potential no-payout if your installation creates a fire.
This is pretty much a myth. Insurance pays out even if you cause a hazard, as long as it's not intentional (i.e., not insurance fraud). Talk to any insurance adjuster: undisclosed DIY is not enough to deny a claim.
What happens instead is that if you make a claim and the damage is due to stuff you didn't tell the insurer about, they will drop you right after they pay. Another possibility is that if they do any proactive inspections (e.g., drone fly-bys), they can decline to insure you or drop your policy.
A more substantial problem is that this page sort of oversells what they're pitching. 1.2 kW of solar power is a fraction of typical household usage. 2.4 kWh battery storage also isn't a whole lot. And yeah, it's cheaper than paying someone, but if your roof starts leaking, it's gonna cost you and you have no one to sue.
> 1.2 kW of solar power is a fraction of typical household usage.
Yes and no; it really depends on what kind of house you have, how many people live there, and (culturally?) where you live.
I have an 1800 sqft condo in San Francisco, and a 3.6-4.0kW solar system would be what I'd end up installing if I were to do it the "normal" route with an installer and all the "red tape". Yes, that's obviously 3+ times the 1.2kW demonstrated here, but even a system like that would be useful for me to reduce my electricity costs (especially given where I live).
I know people with more modest electricity needs than I have. I also know people who have 16kW of solar on their roof and that still isn't enough to avoid pulling power from the grid sometimes. So: yes and no; it depends.
I never planned & priced out battery storage, but, sure, 2.4kWh would be pretty low for my needs, but it would still be useful.
It's just weird that the article title includes the phrase "energy independence", when the author admits that they still pull more than half their usage from the grid.
my wife and I managed to get to an average load of 100 Watts (2.4 kwh per day) for months at a time when we lived in San Diego, albeit with no a/c and gas heating/cooking/hot water. Modern appliances generally don't need much.
Fire is one thing, if someone gets toasted the wrongful death lawsuit is going to be out of control.
> as long as it's not intentional
I think this could be considered intentional, because in most countries, connecting this inverter to anything (source, sink) would require certification (+tests), as it doesn't have standard electrical outlets (it varies from country to country, but in the countries I've seen, either certification is required or connecting wall/ceiling lamps is exempted from this, but verification must be done afterward).
It's a code violation, not insurance fraud.
I read about this often whenever I'm looking at guidance for one of my hobbies, and often people are dealing with it in their garage. Some jurisdictions are more okay with DIYing than others, but it's all too common that someone is taking 240V, 30A and going to an enclosure that they built to get 3+ HP/2+ kW at 240 or 480V, three phase.
The common refrain is that your insurance will deny your claim.
The response that people get when they call their insurance is "you pay us to cover you even when you do the wrong thing". Just like how your auto insurance covers you when you rear-end someone while drunk as hell, when you drape way too many lights on your crispy dead Christmas tree, or when you fall asleep and light your drapes on fire with a cigarette.
Intent is when you set out to cause an accident.
(You should probably read your actual insurance policies before considering my not-a-lawyer American-centric comments.)
> It's a code violation, not insurance fraud.
I think nobody mentioned about insurance fraud. There is a difference between a accidental mistake, not knowing what your doing, and knowing that your bypassing regulation willingly.
This type of installation needs to be reported to the insurance company. Remember, coverage applies to the state of your vehicle/home/property. If you DIY your own power source, the insurance company when informed about it, may drop your coverage.
If they know about the installation, its much harder for them to deny a claim. But a hidden installation like that, is a factor in claim denying.
And we are kind of ignoring the whole "your not just putting yourself at risk but also all the other people" issue".
It really couldn't. "Intentional" as it, you destroyed your property on purpose. Not "you were a dumbass and caused damage", not "you didn't apply for a permit and caused damage". Insurance covers stuff like that, because otherwise, a good half of claims could be getting denied. Basically all kitchen fires are "dumbass moments", for example.
The third option is hiring someone to certify it, usually requires submitting the plans beforehand. Afaik up to 800w you can do a lot DIY here but upwards you needs certification.
> What happens instead is that if you make a claim and the damage is by some stuff you didn't tell the insurer about, they will drop you right after they pay. Another possibility is that if they do any proactive inspections (e.g., drone fly-bys), they can decline to insure you or drop your policy.
This is also a pretty bad outcome.
Anecdata disagrees; insurance will reject payouts aggressively. I know someone whose house "coincidentally" burned down while his neighbor had a bonfire, and his insurance fought him for months.
Insurance will fight, but they have not the final decission. Here in Spain they were denying thousands of payouts for car accidents if the car was overdue in their ITV (yearly state mandated revision). But the judge had different thoughts, and they had to pay.
Big difference between refusing payout because of expired ITV and this installation.
If you alter your car its electrical harnas wiring and this creates a short somewhere, resulting in your car burning down ... that is a whole difference situation then missing a mandatory inspection. One is deliberate alteration of a vehicle and one is a inspection of condition.
Most insurances have a lot of protective language (for the insurance company), that often comes down to "everything needs to be code compliant/manufacture original/...".
The bigger the damage, the bigger the chance that insurance companies will fight you. If the above mentioned installation creates a small kitchen fire that cost a few 1000 bucks, they probably are not going to fight it.
But what happens if the above mentioned installation burns down the building, kills 5 people... Do not forget that the other neighbors / building owner's insurance companies, will go after your insurance if you are identified as the cause.
The issue is that if you go to court, and a fire comes from your apartment is from a accident, or a state like this, courts are willing to side with the victim party. But if a fire is the result of your own "tampering" with devices, electrical, etc, there is a very, VERY high chance that the court will side with the insurance provider. Insurances are not blank "do whatever you want, you get coverage" type of deals.
By assumption this is a rental. If I were the landlord and saw this I would be worried, but the tenant doesn't have all that much to worry about beyond their own stuff. And dying I guess
And harming others and their belongings. This opens one up to liability if the harm spreads beyond your own apartment? I'm not sure but it seems so.
So this is terrifying for all the reasons mentioned below, but the _core_ setup where it is not connected to the utility and acts (basically) like a solar powered UPS is really attractive to me.
All the commercial solar setups out there spend a lot of effort pushing power back to the grid, when all I really want is this configuration to all my outlets.
Does anyone know of a setup like this? Basically a power bank that charges primarily from solar, secondarily from the grid, and provides my normal panel with power through an inverter (or panels/inverters, I actually expect). Feeding back to the grid seems more trouble than its worth...
You want what is called a AC coupled system. Basically, you put something like a charger/inverter/mppt just upstream of your breaker box so that downstream of your breaker box you don't need to change anything. You can find solutions that are a all-in-one like this one [1]. This particular product outputs up to 5kw on a single phase to your breaker box. So if you need more power you either wire 3 of them in a 3-phase system, or in parallel on the same single phase.
Finally, from the settings you can stop the unit(s) from sending power back on the grid so that you don't have to deal with that hurdle of changing the meter, permits, ... .
I linked an example wiring here [2]. I don't work for Victron, but I am just an happy customer :)
[1] https://www.victronenergy.com/inverter-charger-mppt/multi-rs... [2] https://www.victronenergy.com/media/pg/Multi_RS_Solar/en/app...
I’d be surprised if any electrical utility would be ok with connecting something like this without a certified transfer switch in place.
They are certified. In the sense that if the grid goes down it won't send electricity into it regardless of the settings you have. If you set it up to avoid feeding back energy it is completely transparent from an utility operator perspective. This is at least what the electrician that signed off my installation said and it works for the EU grid. Not sure about US or other parts of the world.
Remember: the best and easiest transfer switch is a physical interlock which costs $50 and doesn't wear out or fail, etc.:
https://www.geninterlock.com/product/generator-interlock-kit...
No certification required. Code compliant. Idiot-proof.
Seconded. You do need inverters that are able to work in island mode, which they definitely are not not all capable of doing.
Yes. As someone else noted, there's an excellent community on reddit for /r/SolarDIY with a lot of people who do this. The standard setup is to buy an offgrid inverter that will take shore power. Size your unit to handle your entire house. Throw it _behind_ your electrical panel so that it feeds all of your house. You're basically building a DIY whole-house battery backup + solar.
The EG4 gear is really popular for this. Don't go quite as cheap on the inverter or batteries as the OP did - you want something reliable, and for doing whole-house you want rackable batteries that you can easily parallelize and that have controllers you can talk to.
This isn't exactly what you want, but you could get the same kind of breaker interlock used for traditional generators and use that for the solar inverter. The downside is that you can't blend grid and battery power at the same time, but this may not actually be a problem in a practically sized setup where solar is the primary.
The issue is cutting off your inverter from your grid without also cutting off your outlets from the grid. The ways I've seen to do this are to either put some clamp meters on your grid connection and configure your inverter to a "zero export" mode that'll scale depending on your current usage. Not sure about the legality of that; I'm sure it depends on your locality.
Or to put your outlets on a subpanel with the inverter controlling the feed to that subpanel. Maybe with a 2nd lockout connection to the main panel so you can do maintenance on the inverter without having no power.
Our inverter lets you set it so that it doesn't do any grid export, and otherwise sits between the grid and the normal main breaker panel.
If you do this, I'd highly recommend that you put a transfer switch in place that lets you connect the grid back to the breaker panel with the flip of a lever, and cut the inverter out of the loop. That way, if the inverter ever goes down for whatever reason, you can cut it out and do maintenance on it without any "why is the power still not on".
If you want that, just buy a Bluetti or Jackery.
You can DIY a system like that in the article, using better and/or cheaper components as needed for your use case.
I don't live in the states, but I have a "home energy gateway" which is to say in human: a big switch that isolates my house, solar and batteries from the grid.
I think the generic term is "islanding" (could be wrong)
The downside of my system is that it takes a non-trivial amount of time to switch to island mode, which means lots of computer things reset during the process.
So you don't get 100% uptime, but you are able to carry on when there is an outage.
Ecoflow will sell you rather respectable boxes that contain a battery, and MPPT charge circuit, and an inverter-charger all in one. And those boxes have real BMSes inside, too, unlike this sketchy setup.
Isn't that just... the setup in this article?
Like, yeah, there's some sketchy stuff with connecting those loads to this over extension cords snaked all around the house, but this setup is basically what you're asking for.
GP is asking for the non sketchy way, that lets them use their outlets etc. Which is not trivial because if you still want to be connected to the grid you need to make sure you don't feed power back into it when it's not expected, like during a power outage.
Doing something like hooking it up with a suicide cord is asking for absolute shitheaps of trouble. If you are feeding your outlets, you run the very real risk of backfeeding the grid and electrocuting an unfortunate lineman when the power goes out. You've basically got to get the utility to do this for you, as you need a real transfer switch and their explict buy in, as the only safe and correct way to do this is on the utility side of the distribution box. Doing that basically means getting setup to feed back to the grid as far as I've seen anyways.
> Does anyone know of a setup like this? Basically a power bank that charges primarily from solar, secondarily from the grid, and provides my normal panel with power through an inverter (or panels/inverters, I actually expect). Feeding back to the grid seems more trouble than its worth...
You need to look for off-grid inverters. They are now really popular in Ukraine because of constant power outages.
They are also getting incredibly cheap you can buy one for less than $1k: https://signaturesolar.com/eg4-6000xp-off-grid-inverter-spli...
The state-of-the-art are inverters that can seamlessly blend off-grid and grid-tied functionality, so you can both export your energy to the grid (if you have a surplus) and smoothly fall back to the battery power if the grid is lost. And they can even control standby generators in case the battery is gets low and there's no grid power.
What blows my mind, is that you can even parallel them together to get more power if needed. They even handle the grid synchronization without any voltage spikes.
I'm familiar with this model: https://www.santansolar.com/product/eg4-18kpv-hybrid-all-in-...
Hmm.
"Warning: Potential Security Risk Ahead
Firefox detected a potential security threat and did not continue to sunboxlabs.com. If you visit this site, attackers could try to steal information like your passwords, emails, or credit card details."
site was deleted / removed
https://web.archive.org/web/20251005022124/https://sunboxlab...
Safari too.
Balcony solar kits are popular in Germany which are a more legit version of this.
The main thing I would be nervous about is the panels are claimed to be "rated for 120km/h winds". Presumably thats if they are bolted down? Just laying them down loose on the roof seems like a bad idea.
Yeah I came looking for this comment. I’m in Florida, USA where high winds are the norm. A big shingle sitting there not tied down would flip real quick.
On the one hand I like this... on the other hand, the electrician's assistant in me that tries to be as NEC-compliant as possible is absolutely cringing at a few of the pictures on there.
With that said... a few hundred more dollars, and this could be a proper setup with a proper load centre, breakers, and so on. Simply replace a lot of your home's existing wiring.
> Simply replace a lot of your home's existing wiring.
Seeing as the entire project is by and mostly for renters, that's not feasible.
Do said people plan to take everything down when the landlord comes over?
Otherwise said renter will quickly find themselves in violation of most lease agreements for creation of hazards on the property.
The article author claimed they got their landlord's permission first, so I doubt they'll be taking it down when the landlord comes over. They'll just take it down when they move out.
Also... I lived in rented apartments for more than 15 years, and the only time a landlord entered my unit was one time when I explicitly asked her to (there was a water leak, and I was about to leave town and wouldn't be around to let the workers in to fix it). Is this a normal thing? Are landlords constantly visiting their tenants?
I'm a landlord for a property in the UK, I have an agent who does this kind of thing for me as I don't know the regulations and also I don't live in the country, but yes property visits are normal… at least in the UK.
They don't do smoke alarm inspections? AC filter replacements? I've never lived anywhere where they didn't come in multiple times a year just for those things.
Depends. Here the landlord is responsible for providing working smoke detectors at move-in time but the tenant is responsible for periodically testing them and replacing batteries.
It mostly boils down to how nosey your landlord is. If they are constantly stopping by to inspect things or change filters more than a couple times a year it’s probably an excuse to see what you’re up to.
> It mostly boils down to how nosey your landlord is. If they are constantly stopping by to inspect things or change filters more than a couple times a year it’s probably an excuse to see what you’re up to.
Really depends who manages your building. We had the most issue with the landlord who also manages the building. Like tons of inviting themselves over, very nosy and intrusive.
When we moved out and the final inspection date. We cleaned everywhere that is logical ... ground, windows, bathroom, sinks, tubs, glass, kitchen, drawers, .. you name it.
They then demanded on the move out date, that we clean above the doors, i mean, the flat part above the internal doors, outside some small toilet window that had not been cleaned in 10+ years. We even told them, why is this on us when clearly you did not do so with the previous tenant (we only lived there 1 year). No no, it became that dirty in that one year. Yeaaa, bull... May have something to do that we are "foreigners".
Plenty more crazy stuff... locations where you do not even think about like ducting. Imagine when you read this, look around, and imagine the spots where you never think about cleaning because its kind of crazy. They really looked for every excuse to deny our deposit (did not work). We had plenty of pictures from our move in date, and used them against the landlord.
Where as the building we are in now, beyond the move in date, not a single inspection or anything like that. Sure, a few times that they came to do work, like replacing the smoke detectors, or painting, but those are all 3th parties.
Learned the lesson to never rent from somebody who is the landlord and manages the property at the same time. Too much trouble.
I've never had a landlord come into an apartment or house I'm renting.
(Except when the landlord also lives there.)
We get 2-3 power outages every year where I live. Mainly due to trees with ice/snow/wind. My solution was to buy three power banks. A 500Wh, and a couple of 300Wh. I have a pluggable camp fridge too and a gas fireplace. So one battery powers the fan in the fireplace, another for the cooler to keep the food from spoiling. And the third one for a couple of the lights (with LED bulbs). Works great and we can handle an outage that lasts about 4-5 days. Also we got 4 of these rechargeable lanterns for lights around the house. I just keep the batteries and lanterns charged. Really easy and my investment is about $1000.
Do you mean 500Wh rather than 500kWh? 500 kWh would be around 10 EVs worth, and looks like it costs around 700k [0], but 500Wh seems to be a common size for portable power stations [1]
[0] https://www.backupbatterypower.com/products/516-kwh-industri...
[1] https://www.ankersolix.com/products/535?variant=497024349310...
I think you're off by a couple of orders of magnitude... 500Wh and 300Wh maybe? Or 5kWh and 3kWh if you got a very great deal? Your investment would be orders of magnitude more than $1000 for around a total of 1MWh!
Thanks for pointing that out. Yeah I meant Wh not kWh. Oops. I fixed my post.
Looks like the site's SSL cert is having some issues.
Actually, the whole page appears to be 404'ing now?
Glad I'm not the only one. I was disabling ad block, switching devices and browsers. It's gone.
Related:
Show HN: My $1k self-install, off-grid solar backup build for renters - https://news.ycombinator.com/item?id=40025195 - April 2024 (229 comments)
Suppose I own my house and don't feel like running a new set of wires thru my house, so I'm comfortable separating the panel into a downstream solar-capable subpanel and a real battery stack, but want a similarly thrifty and red-tape-free setup (which never backfeeds the grid). What other pieces of equipment could I substitute?
You can pretty easily setup a subpanel with a feed-in outlet and an interlock so you only have the feed-in or the grid breaker closed, but not both. Something like this [1], but you need to shop to match your panel.
That's thrifty; changing a panel/building a subpanel probably needs a permit, but shouldn't need utility approval. A transfer switch is an option too, but not so thrifty, and if you an automatic transfer switch, they usually work the other way (use grid if available, fail to local generation), but you could probably make it work.
[1] https://www.geninterlock.com/product/generator-interlock-kit...
Get a transfer switch. It’s a 30 minute install by a utility or electrician.
Victron multiplus ii cx could be a good option.
Depending on where you live, systems that you just plug into the wall are legal up to a certain wattage as long as they don't backfeed into the grid
I've been living in a rental for a while, and I have a woodshop in the garage. I've been really wanting to have a 220V outlet to run some bigger power tools, but if figured doing that would require hiring an electrician to come do some work in the breaker box. This has me curious if I can do something like this just to power some stuff in my garage, and also potentially charge an electric car.
Hiring an electrician is going to be cheaper probably, depending on the length of the run and how annoying the location is (and if your panel has enough capacity to spare). Unless your landlord is an asshole they probably won't care, in my experience, as long as you get a qualified person to do it. You're basically improving their place so it's not a hard thing to get approved.
Btw for the second part, you _can_ charge electric cars over just normal 15amp circuits you already have. It's just slow, so you'd only want to do it for nightly charging and it may depend on your commuting range if it'll work out or not.
You could get something like an eco flow battery, charge it on your 120v service and then use its inverter to run your intermittent 240v loads. IIRC their models support being in charge and invert mode simultaneously, so you wouldn't have to swap plugs or change settings throughout the day.
The Delta Pro series is capable of running a 3 ton AC condensing unit, so if your tools are less demanding than this it should work out.
Does that mean all of your appliances, which should supposedly each run on a separate line, now are all plugged on a big single-line powerstrip? Sure, this single-line is only used when battery and sun are out, but when it happens...
Since the inverter is 3 kW, and the battery is 2.5 kWh, you don't run many appliances off it. Hopefully it shifts your air cooler's peak of consumption away from the most expensive evening hours. You can probably cook at daytime directly from solar power.
When the battery is depleted, you, I suppose, just pull the plug from a battery-fed power strip, and push it into a regular socket.
I would put 3x the battery capacity, which would add about $500-600 to the cost.
https://web.archive.org/web/20251005022124/https://sunboxlab...
What would change if you wanted to do something like this but for an EV? You already have a large battery, you can make decisions like "I need to be full for my road trip tomorrow, so fill from the grid", but you can just trickle charge from some fixed solar panels throughout the day most of the time. I think amperage can even be negotiated via the standard EV charge cable.
You’d need a bigger kit. WIll Prowse has many guides on these. https://youtube.com/watch?v=rRqV8BHE8lY
Ugh, these two-lead LFP batteries without any sort of BMS communication are fairly nasty devices. The inverter/charger does not know the maximum safe charge or discharge current, the cell temperature, the cell balance state, or really anything else except the voltage. If the actual BMS in the battery (assuming there’s one in there at all) wants the charger to slow down, it has no way to tell it to do so. The charger has no way to know what it needs to do to get the cell balancing circuit (if any) to work. And the BMS (again, assuming it exists) can’t even communicate the state of charge to the inverter/charger.
At least this particular setup uses a somewhat dignified 24-ish volt setup instead of the usual awful “12V” that is often seen in this genre of battery.
BMS <-> "solar inverter" communication is not required. All LFP batteries that aren't raw cells have a BMS, which have over/under voltage protection. A bad charger isn't going to do anything.
There's also nothing wrong with 12V setups (see all the RVs that are out there).
> BMS <-> "solar inverter" communication is not required.
It’s “not required” in the sense that it works. Poorly. Have you contemplated how balancing between paralleled “12V” LFP packs works? LFP has a voltage vs SoC curve that is very unpleasantly flat for purposes of cell balancing without intelligence, and almost no intelligence is available in these arrangements.
> Theres nothing wrong with 12V setups (see all the RVs that are out there).
There is so much wrong with them that it’s hard to even know where to start.
Let’s suppose you have an RV-like setup that is designed to power one single 15A 120V receptacle. That’s 1800W, which is pretty small by the standards of modern inverters. It’s also 150A at 12V. Want decent efficiency? That means you want to lose less than, say, 2V on the wires, so you need to carry those 150A over a round trip resistance below 13.3mOhm. If you use the ABYC ampacity table, that’s 2AWG or larger wire. Fortunately 2AWG will carry 150A a respectable distance without excessive voltage drop.
Now, 150A is a lot of current. 150A will make massive sparks, light things on fire, and weld sizable pieces of metal even if 12V is unlikely to electrocute you. And you’re feeding that wire or bus in multiple places (because you may have multiple batteries and a beefy charger), so you remember to put giant 150A fuses or breakers at all the feed locations, right?
But wait, 12V needs below 0.08 ohms to produce 150A. Want to comfortably blow a 150A fuse? You need well below 0.08 ohms total resistance in the entire circuit, including the fault. If you have a high resistance fault (and “high” could be 70 mOhms!), you will never blow the fuse and you can produce literally kilowatts of heat. Crispy! (Your house likely has circuits bigger than 150A, but it’s at a voltage that can much more easily trip the breaker, and in civilized countries there will be some sort of RCD as well.)
Oh, and that 2AWG cable is expensive, hard to bend, and requires actual skill to terminate well. And modern systems often target powers well above 1800W.
At least in a car, the high current portion of the 12V system is made and tested in a factory. And it still makes amazing showers of sparks if anyone messes up a jumper cable. There’s a reason that car makers want to move away from it.
So I stand by my claim: 12V sucks.
Refreshingly straightforward! The wires would drive me insane, though.
Ya, this all seems good except for the custom wiring, which seems like hell.
This irresponsible.
Power distribution centers are not power strips and there's a reason for that
Yes, we are on the cusp of self-pluggable home solar solutions.
No, this is not the way.
Assuming the linked products in the article are the items in the pictures, that power strip is a metal enclosure, not plastic
Plastic distribution boxes are actually really common in residential installations in Europe, Australia etc. The UK standard has changed to metal now for fire risk but plastic is common around the world.
It’s more the grounding issues and lack of a properly sized circuit breaker to protect the extension cords etc.
What is wrong with plastic there? I think possible lack of grounding and messy power cabling are bigger hazards.
I think plenty of folks just have a vague understanding of electrical codes and say stuff like that to impress others.
Generally speaking, you're just not supposed to do permanent electrical wiring with extension cords and power strips, especially not for stuff that goes into or through walls. This has nothing to do with plastic - you have plenty of plastic in electrical boxes, outlets, PVC conduit, etc. Cable insulation is plastic too.
The electrical code doesn't want you to put extension cords in the wall mostly to make sure that the connections can't come apart, that the comparatively softer and more delicate wires aren't easily crushed or abraded, and so on.
This project definitely isn't done the way you should do it if you had a real budget dedicated to it. Is it a death trap? Meh, I've seen far worse extension-cord contraptions in US homes.
Two things come to mind: 1) if any arcing occurs, a metal enclosure will shunt to ground and (hopefully) trip a breaker; 2) in the event of an overload, plastic melts which might result in a fire.
The fact that this is the most appealing option is an indication that our electrical system, both equipment and code, are failing to address people’s needs. If you get a quote for a hybrid (on and off grid) system, they’re absolutely unaffordable.
Is there any calculus for safety in your affordability tradeoff ?
The website has been taken down, now GitHub pages returns 404
https://web.archive.org/web/20251005022124/https://sunboxlab...
The more common term for the unit is a solar inverter or off-grid inverter.
I run a few of these on an off grid property and they're totally fine. I would be wary of a cheap no-name brands. I'm also be wary of running extension cords all over the place.
If you have the space (a mechanical closet?). I'd suggest getting a separate inverter and charge controller. These all-in-one units have fairly high idle inverter draw.
I remember seeing this on HN a couple years back. At the time, this made financial “sense”. But nowadays, you can get an all in one refurbished for sub $700. This way, it’s truly portable and all you need to worry about is getting the solar panel power to your battery generator.
related YC discussion about solar batteries on balconies in Germany: https://news.ycombinator.com/item?id=45485806
This is hard to share in a lasting way. The post I want to share is just the main page which could change and loose context after some amount of time. I recommend a subpage for articles to help long term sharing.
The US really needs to get onboard with "balcony solar" or "plug-in solar."
> small solar panels that can be easily installed on balconies and plugged directly into a standard wall outlet, allowing users to generate their own electricity.
I believe this is common in Europe. They’ve figured out some way to make it safe for the grid and line workers.
I have been thinking lately about what it might take to run a small house entirely off grid. My thought was that if you could build a separate battery shed that is away from everything and then fill it with like 100 kWh of batteries charged by a 30 kW solar array, then you could presumably run power from the battery shed to your house as if it was a normal utility hookup. But then again I have no clue if a town zoning office or building inspector would have a fit over a setup like that.
The easiest is usually to have wheels on the house, and then power it as a trailer/rv.
I am thinking more something that has a high spouse approval factor. 1200 sqft, 2-3 bedrooms, normal plumbing and sensible HVAC.
I’m thinking something that is technically a large RV trailer “docked” into a non-house structure that provides additional space.
All major plumbing and appliances and power are in the trailer, the extra “rooms” have nothing much but lighting.
Not sure how it’d work in practice.
Powering your house is an advertised feature (with additional equipment) of a few electric cars.
e.g. https://electrek.co/2025/09/28/yes-an-ev-really-can-power-yo...
To go off grid, you'd need a source of power to the car that wasn't your house.
The battery is the scary part. How do you know you’re not getting some cheap ass china junk that’ll burn your house down?
I’m amazed that you can legally sell any device that plugs into a normal receptacle and generates power for that circuit.
None of the equipment in this article does that. It takes power from the grid the way any appliance does; it optionally charges by solar; and it provides power the same way a UPS does, using ordinary female power sockets.
But there are devices out there that do feed power over the exposed prongs of a male plug. They're called "suicide cords" for good reason.
Ah. I saw a whole thing about solar panels for balconies that did exactly this. I skimmed the article and thought I saw the same idea. I missed that it’s just charging a battery.
Ah! These…
https://news.ycombinator.com/item?id=45485806
Why? It's just a battery charger. They are basic-ass components and there are a zillion UL-listed lithium chargers that are perfectly safe and in common use.
There a many problems with this article, but the fact that it includes a battery charger is not one of them.
That's a really good price for the sizing.
Like others said not sure about that wiring though
> The secret sauce is that the sunbox is usually off-grid and never pushes power back into the grid. The only reason it's connected to the wall at all is that if it runs out of power it can pull energy from the wall.
Ideally we all could push power back to the grid & that ought not be hard, but in point of fact that can be a huge barrier.
It's not capable of generating as much power, but I love what Zoltux and many others are doing: attaching current sensors to the main breaker box, and using that as feedback to make sure the solar is never generating so much power that it pushes to the grid. Pretty mild 800w power on the Zoltux. https://zoltux.com/
The existing DJI Power 2000 added this capability with a recent software update, if you have a compatible energy meter! Can accept up to 1800 watts of solar power. I'm not sure if there's any difference between this kind of setup and a european balcony solar install? https://www.renewableenergymagazine.com/pv_solar/dji-power-2...
Also, this submission showed up two years ago. 236 points, 230 comments. https://news.ycombinator.com/item?id=40025195
If I was paying 55c/kWh I'd freaking hire someone to pedal to generate the power. Thats insane. No wonder it pays off quickly!
link shows github 404 page
They took this down so quickly. Bad examples are great to learn from. I don't get all the hate, and it just seems like a bunch of bullies found out and put the red tape on it. Don't you think "burning a house down" is a vast over exaggeration? I wouldn't trust any professionals using such intimidating tactics.
Do they not teach "the boy who cried wolf"? It doesn't get worse than claiming this stuff will burn someone's house down around with everyone around them.
The amount of gatekeeping in this thread is nuts.
The idea here is totally reasonable, it just needs some of the parts more right sized etc
"Just" is doing a lot of work there. Maybe the idea is reasonable, but the setup as-is is not safe, and there's nothing in the article that would tell you that, or tell you what you need to add to it to make it safe. Many people might read the article, think that it's all safe (because they don't have the knowledge required to properly evaluated it), and then burn their houses down.
Not saying this is the most unsafe thing I've ever seen or heard of, but we have electrical codes for a reason... because buildings have burned down and people have died.
It falls into that "soft bigotry of low expectations" zone. There are intro articles and advanced articles; the advanced ones don't need to spend the first 1/3 of the volume talking about safety.
I don't see any gatekeeping, I see safety concerns.
Great for sheds? Or for addressing a high use area like kitchen or your server room?
A setup like this seems perfect for a little shed to code in that has solar power.
I've wanted to build something like Roald Dahl's writing shed: https://youtu.be/AsxTR09_iWE?t=294 for a while.
I live in a climate with cold winters though, so I hate to invest in something like this and not be able to use it for a significant part of the year. I guess I could put a small pellet or wood stove in it..
If you don't need/can't use the grid backup you could probably get away with a cheap-ish Ecoflow/anker/etc battery with some solar plugged in and save a few hundred bucks
screams in fire marshall
This is like a guerrilla solar recipe from the anarchist’s cookbook.
The author doesn’t explicitly dissuade people from plugging in another multipoint/powerstrip/plugstrip into the end of the extension cable you’ve run into the other room. So I will. Don’t do that. There are plenty of low gauge, cheap extension cables out there which will degrade fast in this setup, and may cause a fire.
Also, if your landlord is okay with seeing this setup they probably don’t have insurance they’re worrying about, and are simply making sure you’re not actively destroying the property (rather than potentially destroying it with the fire hazard).
> There are plenty of low gauge, cheap extension cables out there which will degrade fast in this setup, and may cause a fire.
But I used the highest gauge I could find! I looked hard, but I couldn't find any with more than 16 ;p
Good news! I looked on Amazon and I found one that goes all the way up to 18! It also says ‘fully copper coated’ so you know it’s good. (/s, please never do this)
I often downvote posts like this, on the grounds that excessive safety nannyism doesn't belong on a site called Hacker News... but having seen what they call a "2500W power distribution strip," yeah... have an upvote or three.
Assuming the linked products are the products in the picture, the strip is a product from Southwire that is claimed to be rated for 20 amps / 2500W and southwire is an established and known brand. It is listed as being for “temporary” installations and I’m not sure I’d want to run that load through it all the time, but it’s probably not that bad.
I can't find a mention for the voltage, but if it's 240V, that seems like about 10A, which is standard for these strips, no?
It's 120V. Pushing 20A continuous through that kind of wiring is less than ideal.
First of all, let's assume less than ideal conditions so base our calculations on 115V. 2,500 watts is going to be 21.7 amps; assuming a continuous load (which is pretty reasonable for a whole house) is going to need a breaker and wiring that's rated for 125% of that, or 27.2A.
That means the supply needs to be #10 wiring and should be fitted with a 30A breaker at the disconnect. A temporary power tap is not a suitable disconnect. And I highly doubt it's got 10 gauge wiring.
Ah yeah, at 120V that is definitely not going to cut it.
All the prices are in USD, and the outlets are US standard, so this is likely 120V. So 20 Amps, not 10.
Dont fuck with electricity. I think the intuitions people have are based on home installations with RCDs, fuses and earthing and proper cabling before it gets to that socket. You then plug in a distribution to draw 100w for your devices and maybe the occasional 2kw for the vacuum cleaner for 5 minutes if too lazy to use another socket. Yoy not running full house load through it all day.
Eh, what about importing at 15Kw, exporting at 5 and charging batteries at 500A@52V?