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120V Inverter generator, use a 120 -> 240V transformer to the input of inverter?

SparkyJJO

(un)Certified Arc Generator
Joined
Jan 31, 2022
Messages
1,634
Location
Ohio
Before I got the solar, I got a Champion 3500W continuous/4250W peak inverter generator to run critical stuff in case of an extended power outage.

My inverter I have now (Outback Radian) uses 240V split phase input, and has a generator input that can be current limited to the size of the generator. Of course, the problem is the 120V generator vs the 240V input required.

I have a 120V/240V 1.5 kVA transformer sitting around that, if I'm reading the nameplate correctly, can be center tapped for 240V split phase output. Could I use that between my Champion generator and the Radian inverter so that I can charge batteries if solar is too pathetic to do much for a couple days? Obviously I'd be limited to about half of what the generator could actually handle.

The other (maybe better?) option I suppose is to run the generator to a 120VAC LFP charger connected to the bank in parallel with the Radian, and use that to charge from generator when necessary. I could roughly double the recharge rate that way vs going through that transformer. It would just require buying another piece of equipment and wiring.
 
The transformer method seems like it should work, but do you know what kind of inverter it is in the regard that it can only charge batteries while in bypass? Those kind would need a large enough generator to charge and run house loads at same time.

I like your second idea better, to just charge batteries directly using generator to standalone battery charger to battery bank. Then you can size the charger to the max continuous load of the generator and get best fuel to charge ratio. I'm going that route myself.

In my case, my current generator is capable of 240v (with two 120v legs), so I bought 2 AIMS 48v LFP chargers and will hook up one on each leg. Because my inverters require to go into bypass (LV6548), in order to run its internal chargers, and my generator (for now is my Prius 5 KW UPS 240v split-phase inverter until I fix my two 5.5 KW Onans), would not be so good for that. Besides, my Onans are only 120v so they wouldn't have two hots 180° apart to feed each leg on my LV6548s...
 
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Oh, I totally didn't think of the pass through need. Derp. Thanks for the reality check!

Yeah sure no prob at all...

I'm also doing straight battery charging right now on my present motorhome 12v system since it has a Magnum inverter which needs to run in bypass in order to charge batteries, so instead I have the 4 IOTA RV style chargers (two DLS-45 and two DLS-55), all four of them plug into my Prius inverter (two chargers per leg) and charge a total of 200a to my 12v LFP bank.

It works nice, because it doesn't care what the inverter is doing (it can be on or off), the Victron solar chargers can still charge too as fast as they want as well. I am now sold on this method after using it already. Have the same type of thing lined up for my 48v house system I'm assembling soon using those AIMS chargers I was talking about in my last post.
 
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