[cpfohl]

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...

[marcyb5st]

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...

[SoftTalker]

I’d be surprised if any electrical utility would be ok with connecting something like this without a certified transfer switch in place.

[marcyb5st]

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.

[rsync]

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.

[jacquesm]

Seconded. You do need inverters that are able to work in island mode, which they definitely are not not all capable of doing.

[dgacmu]

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.

[yummypaint]

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.

[ThatPlayer]

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.

[cyberax]

> 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-...

[ericd]

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".

[caymanjim]

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.

[amluto]

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.

[KaiserPro]

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.

[lambda]

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.

[andreareina]

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.

[rpcope1]

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.