Solar, Battery, Generator, Utility combination

[ggunn]

I have never personally seen such a system. I imagine it would work. It would certainly be an interesting set up.

I guess you could have a off grid style solar with battery, then off the inverter a reverse wired ATS with utility connected to the generator input, then down stream from that, another ATS that would start the generator.

I don’t know what ATS would work with that setup though, as 1, you would have to able to program the inverter drop out voltage, and 2, I’m not sure how the ATS would know how/when to switch between inverter and utility, especially when it’s seeing full voltage in both inputs.

I’m still trying to wrap my head around how such a system could be configured. But it’s a fun exercise.

For some definitions of "interesting" and "fun", I guess.

 

[Seven-Delta-FortyOne]

And then there is the whole generator ATS, which throws another can of worms into the mix. And then there is the return to solar when batteries are charged. I’m not seeing how this could work this way, at least not automatically.

 

[Christopher Andrews]

I'm installing a 400A service with two 200A subpanels for a client. He wants a propane generator, solar panels, a battery bank and will be connected to the local power utility but does not want the solar to be grid tied. I know how to install daisy-chained automatic transfer switches for the generator (Generac ATS's are set up for this) but I'm looking for the best options for connecting all 4 sources. So far I've found that many vendors are generator only, some solar/battery only and some are low amperage only.

You could treat it like a small micro-grid — use a hybrid/off-grid inverter to manage the solar and batteries, and let the ATS handle switching between generator and utility. Trying to control all four sources with a single switch usually gets complicated.

 

[ggunn]

You could treat it like a small micro-grid — use a hybrid/off-grid inverter to manage the solar and batteries, and let the ATS handle switching between generator and utility. Trying to control all four sources with a single switch usually gets complicated.

EG4 and Sol-Ark have systems that will deal with PV, batteries, generator, and grid.

 

[bmaclaff]

EG4 and Sol-Ark have systems that will deal with PV, batteries, generator, and grid.

I looked at EG4 and so far, it didn't look lik EG4 had a way to connect two ATS's to one generator. Their solution was to have one PV,battery,generator for one ATS and panel, and another PV,batter,generator for the other, so two of each. It seems common to expect two PV arrays and battery banks, one for each ATS and panel, but I really didn't want to plan for two propane generators.

 

[Master Nater]

the only brand i would even think about going with is solark. i cannot say enough about the system's versatitily, and excellent customer service.

it will allow designs to change with the click of a check-box on the system's screen, as the customer realizes things are not exactly what they want. as battery systems change, they are simply programmed into the inverter(s). those generators, do not need ATSs, as the generator(s) end up tying into the generator inputs of the paralleled inverters. i highly recommend using Tigo dc optimizers before running the dc circuits to the solark inverters, to isolate each panel on it's own.

worth looking into anyhow.

and if the customer is serious about wanting to be off-grid capable, they're going to have to get their electrical usage down MUCH FURTHER than a 400a service. energy saved, is energy not needed to be produced.

 

[Birken Vogt]

EG4 is like the unbelievably cheap version of Sol-Ark and they both seem to be good quality wise.

This system would be simple for me to build.

1. Install a couple of Kohler or ASCO standard 200 amp transfer switches on each 200 amp feed.
2. Construct a single (probably large) Sol-Ark or EG4 basically off-grid battery, inverter, generator system off to one side and split it into the generator input of both transfer switches.

During normal times the poco would just flow right through the ATSs and the BESS would sit off to the side fully charged and idle.

When the poco drops it would switch to the BESS and the BESS would take care of everything by itself just like it does when off grid.

 

[Seven-Delta-FortyOne]

EG4 is like the unbelievably cheap version of Sol-Ark and they both seem to be good quality wise.

This system would be simple for me to build.

1. Install a couple of Kohler or ASCO standard 200 amp transfer switches on each 200 amp feed.
2. Construct a single (probably large) Sol-Ark or EG4 basically off-grid battery, inverter, generator system off to one side and split it into the generator input of both transfer switches.

During normal times the poco would just flow right through the ATSs and the BESS would sit off to the side fully charged and idle.

When the poco drops it would switch to the BESS and the BESS would take care of everything by itself just like it does when off grid.

But he wants a system where the solar and BESS is primary, and the utility is the backup.

 

[bmaclaff]

But he wants a system where the solar and BESS is primary, and the utility is the backup.

Yes, I think the client Would like the solar/BESS to be primary until demand exceeds its ability, then switch to utility, then to propane generator if utility is down.

 

[Master Nater]

But he wants a system where the solar and BESS is primary, and the utility is the backup.

you can set it up that way. you can actually get the system to dump some of the load back to grid (i know he says he doesn't want this) at peak times, or you can get it to store power during low-cost times, and re-use it at peak cost times.

 

[Birken Vogt]

But he wants a system where the solar and BESS is primary, and the utility is the backup.

I knew there was some quirk to this discussion I was forgetting.

In that case, a Sol-Ark or a few (or equivalent) inline would be the answer.

You can set them to zero export, and all that.

Abandon the whole 400 amp idea, you will not want to buy that many inverters anyway.

You could also reverse inputs on the transfer switch, feed the inverter output in the preferred side and utility in the standby side.

 

[Christopher Andrews]

Sounds like a micro-grid setup. From what I’ve seen, it’s usually easier to keep the generator on standard service-rated ATSs and let solar + batteries run behind a hybrid/off-grid inverter, instead of trying to find one box that handles all four sources at 400A. A lot of people split it into two 200A sections, or put PV/battery on one panel with selected loads. Just make sure the inverter has proper anti-islanding, since the solar isn’t grid-tied.

By the way, have you ever installed BYD Blade batteries for anyone? I saw a link https://cmxbattery.com/product/48v-...m-solar-home-battery-for-home-energy-storage/ claiming 10,000+ cycles, which surprised me. I always thought those were mainly for EVs , are they actually practical for home energy storage? Just curious.

BYD Blade batteries are basically LFP, so the long cycle life (8,000–10,000 cycles) isn’t too surprising. They’re used a lot in EVs, but the same chemistry works well for home storage too. The main thing is making sure they’re compatible with your inverter/BMS — many people still go with brands like BYD or Pylontech that already integrate easily with common hybrid inverters.