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Sol-Ark Gen charging question

Averageaviator

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I was considering buying the Sol-Ark 12k sooner rather than later as was my original plan, however, in the manual it states all A/C input to include Gen input must be at 240v. My issue is that my backup Gen setup is a pair of paralleled Honda EU2200i's converted to propane that I planned on using to charge my Battery bank (30kw of Gyll LiFePO 4). So, basically, how would I go about using my honda's to charge my bank ?? Is there a way to use some type of transformer to convert it to 240 prior to the Sol-Ark or maybe buy a cheap 3000W MPP all in one used as a charger only ?? I'm spitballing here !!

I am planning on using setup this for emergencies only this year. I will likely purchase my panels this year also and store them for the 26% ITC until I can figure out whether it makes sense to replace my roof prior to panel mounts and wrap my head around wiring a critical loads panel (may have to hire this one)

thanks all, this is my first foray in the solar life.
 
Most inverters require the same AC input that they output.

Victron sells an auto transformer that will step 120VAC single phase up to 120/240VAC.

My $450 Harbor Freight Predator 3500 is 120/240VAC split phase.
 
This is my first post here. Responding to Averageaviator (the OP).

I did exactly the same thing, including the propane conversion (GenConnex actually). These can run in parallel and the 2nd unit started will synchronize with the first. There are no magic cables or communication for this. It just senses the input from the 1st and synchronizes to it and maintains reasonable load sharing. BUT, thats 120VAC only.

I felt that it would work however to connect each generator to opposite sides of an autotransformer to get synchronized (out of phase) 120/240. Honda obviously would not approve, but it works for me.

I actually bought one of the Victron autotransformers first but it was not going to work because the two sides of the transformer were different by 5% which totally screws up the load balancing. It is not designed for this application - nothing is really. Most dual winding transformers seem to have a few "extra" windings on the secondary so that the losses show up as current, not voltage. So I returned the Victron and bought a Signal Transformer DU-5 which has 4 identical windings - and they were very, very close. With the windings paralleled, this can handle 41A of current which only really flows in the coils when you have a load imbalance. These two generators can just reach that if the entire 4400VA was on one side (unlikely, but possible). I used a 40A dual-pole breaker on the "output" of the autotransformer since in theory these two 20A generators together could push 40A on one side.

I would not try this with a smaller transformer - it won't handle the worst case load imbalance.

If you can find a surplus transformer out there with 2 identical 40A windings, it might be cheaper. I could not, so I sprung for the new one ($700 I think). This DU-5 weighs 90 lbs and barely gets warm with extended operation. The Victron's are MUCH lighter, probably more efficient and have a thermal shutdown mechanism. No idea how often that might trigger. I think both of them can only handle 25A in the transformer core (eg: imbalance current). But the winding mismatch was the deal killer.

I liked the Victron because it includes breakers etc. and is probably quite efficient in the right application, but it just did not meet the unique requirements for this application.

Why you might ask? Two reasons: I spent less than one Honda eu7700is would have cost (converted to propane) and I can turn off one generator and still have 120/240 and reduce fuel consumption. It won't start my well pump (2 of them will) but I can flip that off and run on 1 generator when I only need one. Obviously this is not enough power to be careless and we have to be aware of what we are running. I flip off the breakers for all the bigger loads that I know it can 't handle before I even start it up.

Oh, yes you could hook both generators to 1 side of an autotransformer and it would work and maybe even keep Honda happy, but then you always have current running in the transformer if there is any load on the other leg. I just thought it was snazzier to do it this way.
 
This is my first post here. Responding to Averageaviator (the OP).

I did exactly the same thing, including the propane conversion (GenConnex actually). These can run in parallel and the 2nd unit started will synchronize with the first. There are no magic cables or communication for this. It just senses the input from the 1st and synchronizes to it and maintains reasonable load sharing. BUT, thats 120VAC only.

I felt that it would work however to connect each generator to opposite sides of an autotransformer to get synchronized (out of phase) 120/240. Honda obviously would not approve, but it works for me.

I actually bought one of the Victron autotransformers first but it was not going to work because the two sides of the transformer were different by 5% which totally screws up the load balancing. It is not designed for this application - nothing is really. Most dual winding transformers seem to have a few "extra" windings on the secondary so that the losses show up as current, not voltage. So I returned the Victron and bought a Signal Transformer DU-5 which has 4 identical windings - and they were very, very close. With the windings paralleled, this can handle 41A of current which only really flows in the coils when you have a load imbalance. These two generators can just reach that if the entire 4400VA was on one side (unlikely, but possible). I used a 40A dual-pole breaker on the "output" of the autotransformer since in theory these two 20A generators together could push 40A on one side.

I would not try this with a smaller transformer - it won't handle the worst case load imbalance.

If you can find a surplus transformer out there with 2 identical 40A windings, it might be cheaper. I could not, so I sprung for the new one ($700 I think). This DU-5 weighs 90 lbs and barely gets warm with extended operation. The Victron's are MUCH lighter, probably more efficient and have a thermal shutdown mechanism. No idea how often that might trigger. I think both of them can only handle 25A in the transformer core (eg: imbalance current). But the winding mismatch was the deal killer.

I liked the Victron because it includes breakers etc. and is probably quite efficient in the right application, but it just did not meet the unique requirements for this application.

Why you might ask? Two reasons: I spent less than one Honda eu7700is would have cost (converted to propane) and I can turn off one generator and still have 120/240 and reduce fuel consumption. It won't start my well pump (2 of them will) but I can flip that off and run on 1 generator when I only need one. Obviously this is not enough power to be careless and we have to be aware of what we are running. I flip off the breakers for all the bigger loads that I know it can 't handle before I even start it up.

Oh, yes you could hook both generators to 1 side of an autotransformer and it would work and maybe even keep Honda happy, but then you always have current running in the transformer if there is any load on the other leg. I just thought it was snazzier to do it this way.
This helps out a great deal, thanks for the reply. I just bought the solar edge autotransformer to use with my 240v growatt 5000es to get my 2 midpoint 110 legs, I was gonna buy another to try and create 220v out from the gens but am still working out other parts of the system.
 
I just bought the solar edge autotransformer to use with my 240v growatt 5000es to get my 2 midpoint 110 legs ...

That is a more conventional use for an auto-transformer and should work fine. I'd like to know how well matched the primary and secondary are on that brand?

I should add that I did connect the center-tap of my DU-5 to the "neutral" leg of each generator as well as to the neutral of the house/load. I could not convince myself that this would work with the neutral legs of the generators connected only to each other. Doing this has an impact on the load balancing since the two generators can see different loads and is part of why I needed a transformer with closely matched primary and secondary windings.

The EU2200i generator outputs (like most generators) are ungrounded, so they technically don't have a "neutral" side and a hot side, however they are hard wired to the generator's outlets which do have a polarity, so I took the time to figure out which leg was wired to the neutral side of the outlets and labelled them. This means that both generator outlets will test correctly when they are running in this configuration.

And I should add that the DU-5 has 4 windings - 2 primary and 2 secondary. Each pair can be operated in series or in parallel so the transformer can be used in several different configurations and not just as an auto-transformer. This is a pretty common setup with transformers. I paralleled both the primary and secondary pairs and then wired them together to get a non-isolating autotransformer since I did not need isolation in this application.
 
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