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
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 ...
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”
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.
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.
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).
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.
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.
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 :)
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.
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.
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.
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".
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.
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.
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.
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.
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.
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.
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.
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.
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 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.
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.
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.
> 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...
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..
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).
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.
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
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 ...
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 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.
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.
> 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).
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.
Fire is one thing, if someone gets toasted the wrongful death lawsuit is going to be out of control.
> 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.
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.
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...
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.
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.
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.
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.
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.
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.
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)
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.
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.
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.
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
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.
Refreshingly straightforward! The wires would drive me insane, though.
Ya, this all seems good except for the custom wiring, which seems like hell.
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.
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.
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
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 ?
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.
I’m amazed that you can legally sell any device that plugs into a normal receptacle and generates power for that circuit.
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 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
> 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
Great for sheds? Or for addressing a high use area like kitchen or your server room?
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
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..
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
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.