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?
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...
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...
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, ...
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.
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.
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.
> 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?
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).
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.
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.
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.
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).
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 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.
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 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'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.
49 comments
[ 3.9 ms ] story [ 76.9 ms ] threadShow HN: My $1k self-install, off-grid solar backup build for renters - https://news.ycombinator.com/item?id=40025195 - April 2024 (229 comments)
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...
* 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, ...
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.
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.
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.
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...
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 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.
Like others said not sure about that wiring though
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.
There's also nothing wrong with 12V setups (see all the RVs that are out there).
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.
The idea here is totally reasonable, it just needs some of the parts more right sized etc
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