What I was referring to is actually 2x the Growatt, so it's still 24v, just 2 inverters, and they have a setting to connect them in parallel for 120/240 output
Aaahhh, so other than the power draw issues and where to stick it, yes, you could very well do that.
I believe each Growatt uses 2a on standby and 20a on regular mode. The way I calculate it, that puts it at 600w for one or 1200 for 2. If I'm looking at a 7-10% loss via transformer, wouldn't that mean it's about the same for 2x AIO vs 1 AIO + 1 transformer?
The "Low Power" mode shuts off the AC completely until there is a load of over 50w draw, which means that you could turn on every light in there and still not turn the inverter on. While that's really annoying as it is, it also means that all your appliances will basically be unplugged every time it goes into low power. Your clocks will forever be at 12:00 12:00 12:00.
The 2a regular draw is still 2a * 24v = 50w * 24hrs = 1200Wh/day to exist. 2 units will be double that. Your current battery plan is 24v * 200Ah = 4800Wh. 4800Wh / 2400Wh/day = 50% of battery capacity.
With any setup with the Growatt, my understanding is that the AC goes into the AIO and feeds it in preference to or secondarily to the solar power, depending on my settings. Here are the user manual specs, which I am interpreting that it can take 30-60amps in the same form we're talking about 30a/50a shore power... is that not correct?
That's amps of battery, not amps of AC. So, even if you were drawing 60a from the shore power, that's 60a @ 24v which is only 1440w. 1440w of 120v input power is only 12a of draw from your shore power connection.
This is what I was asking about when I asked whether it would add more options for future ground arrays that may be at different voltages. Again, this would be 2 AIOs linked in parallel split phase. I am not sure exactly how that would work.
Something like 1 Growatt connected to the roof panels and another Growatt connected to the ground mount array? You can do that since you're planning on sharing a battery bank anyways. You could just as easily do it with a much cheaper MPPT controller paralleled in with the Growatt.
I guess it really comes down to value. In my mind, with the space limitations and battery capacity draw, the extra 10% efficiency you'll get out of another AIO isn't worth the $700 unless the autotransformer is about the same cost. Then it seems to still not be worth it.
This was my thought process PRO-50a plug... why does it make you suggest against a 50a plug?
You can get a generator from Harbor Freight that will feed a 30a RV plug and even the cheesiest parking slots with hookups will have a 30a socket. Considering even if you were to get 2x AIO's that would only draw about 25a so it's more a matter of functionality. Going with a 50a plug requires more complex wiring to balance your loads across the legs and might not be available. If you wired it in to feed 1 leg to each AIO then if you used a 30a adapter/socket you would only get charging to a single AIO. If you plan on the wiring to be 120v based from the get-go then there's a lot less hassle involved with it all.
As an example, in my camp/camper there is only 1 slot that could take a 240v breaker (thanks
@smoothJoey , I missed that!) and each side could take half the load from the original 50a plug that was wired in there. If I were to use a 30-amp adapter it would lose 1 leg of that power and either the right or left half of my panel would get no power.
No generator backup. I'd like to be primarily boondocked, but I am buttoning up my backup plan for when I'm on hookups, and I'd like to get my money's worth
Never visit the PNW outside of July-August then.
You'd never get enough sun.
I'd consider anything, but the other options I've found seem to either require a lot more large & expensive components and/or not be able to handle the voltage of residential solar panel inputs.
That's a matter of the parts. Sadly, the cost of an AIO does tend to be cheaper by the time you pay for a mid-range MPPT controller of the same amperage AND a pure sine wave inverter AND an AC charger. The advantages of going component though are something to consider thouth, namely:
1: If the MPPT controller dies, you just replace the MPPT controller.
2: It's easier to find space for multiple small boxes sometimes than larger individual units.
3: Future upgrades don't always require throwing all the components in the trash.
As for the residential panels, a lot of them are in the 40-80v range which means most mid-range MPPT controllers can take a 2s or 3s string, and however many strings the amps rating will allow.
I've pondered this... would 120v lights/etc be as efficient as 12v?
As efficient? No. Simpler to source and wire for? Yes.
They do make 24 and 48 volt lighting.
But not readily available in stores.
Those all in ones, don't handle the neutral ground properly when they are paralleled.
That is dangerous.
Soooo many threads about that too, it's kind of a major issue in the AIO's. Sadly, it's not just AIO's that have that problem.
This is all good noodling here. I still think the AIO -> Autotransformer -> 240v breaker box -> All The Things is the more simple and elegant solution. Yes, it's a 10% efficiency loss, but 10% is far less battery and space than a 1200Wh/day inverter.
If you need over 2700w of power it may be time to rethink your living style and maybe, if worst comes to worst, when all else has failed, maybe step down to a MargaritaMaster 2000.
It’s an experiment of-sorts! I’ve learned a lot along the way, and by no means is that learning done…
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