Here is a question i thought some of you might have a thought toward. I am planning on getting the champion inverter gennie for some general use. However I was thinking about some backup power for my home. Here is my thought. (i do realize that i need to do the following in a safe manner that uses a manual transfer switch to protect the power linesmen) In order to have enough wattage to power some of my home items i would also purchase a second non-nverter gennie and use it to power one leg of a 220 breaker, and the inverter gennie to power the other leg of a 220, both wired to neutral and ground. (Not using the parallel type set-up)The real question is would this cause any issue. - from using inverter/non-inverter?- would two different gennies providing power be a problem for well pump or electric water heater?- would there be too much "distortion" in the power supply to be useful? Other thoughts? thanks!

All lights, appliances etc that run on 120 volts (ie one leg) would be OK but anything on 240 volts would not as the sources would not be synchronized as far as waveform was concerned. They would be "out of phase".Stove, water heater, well pump, A/C etc. would need to be isolated.Personally I don't think it's a "good idea".

No this is a bad idea. Don't do it. The Yamaha/Honda units can be paired because they are inverter based and specifically designed to match line frequency...but even they don't do 220v.

Bad ideaShared neutral..on out of phase wave formsCould fry both generatorsBuy one generator that does 230v

You won't be able to power any 240 vac loads, presumably your pump, water heater, etc. Resistive loads like the water heater just won't work right, but a motor could be quite damaged, as could the generator. They require that the two legs of the input be 100% synchronized. You could power some 120 volt loads off one leg from one generator and some off the other leg and generator, but you couldn't really do it safely. It's against code for anything inside of a panel to be powered from two independent sources, for one thing.Brian

I know one safe way to do it, which was going to be part of a (for now, abandoned) van conversion project:A Victron or Magnum Energy inverter, with two 120VAC sources can easily do the above. You won't be doing dangerous stuff like trying to power individual legs at different frequencies... but the inverter will take the incoming power from both sides, put it in the battery bank, and at the same time, push out pure 240VAC that is clean and up to proper codes. Note, this is not cheap, but this is the right way to do it to have the ability to run a load from two generators at the same time.

2 generators simultaneously for backup power | Good Sam Community

BurbMan
Explorer II
Mar 09, 2015
Even 120v circuits....you could have a pair of 12ov circuits wired out phase with a shared neutral...the circuits would work fine powered in this manner, but you would severely overload the neutral with twice the current it was designed for and probably start a fire. As was stated, 220v appliances would likely fry themselves if powered with 2 inputs on the same phase. Plus you would need 2 transfer switches. This is a BAD idea no matter how you slice it.

The Champions are cheap enough, just buy a second one and run the parallel, this way you have one power cource to the panel, even though 22v stuff wont work. If you need power to 220v stuff then you need a bigger generator.
greenrvgreen
Explorer
Mar 09, 2015
Really? From two dissynchronous sources?

The OP should just buy a Champion 3500/4000, they are ideal for home backup and switch easily from 30a/120v to 15a/240v. If the OP needs more power, get the Champion 7500 at Costco.
2oldman
Explorer II
Mar 09, 2015
mlts22 wrote:
A Victron or Magnum Energy inverter, with two 120VAC sources can easily do the above.
Xantrex Prosine too.
deshemar
Explorer
Mar 09, 2015
The wave form was my first thought as a problem, but I had limited knowledge that I knew you all could provide answers for, thanks!
I will need to do my first thought of getting a bigger second gennie for the house that will be a stand alone solution for the 220 needs.
mlts22
Explorer
Mar 09, 2015
I know one safe way to do it, which was going to be part of a (for now, abandoned) van conversion project:

A Victron or Magnum Energy inverter, with two 120VAC sources can easily do the above. You won't be doing dangerous stuff like trying to power individual legs at different frequencies... but the inverter will take the incoming power from both sides, put it in the battery bank, and at the same time, push out pure 240VAC that is clean and up to proper codes. Note, this is not cheap, but this is the right way to do it to have the ability to run a load from two generators at the same time.
VintageRacer
Explorer
Mar 09, 2015
You won't be able to power any 240 vac loads, presumably your pump, water heater, etc. Resistive loads like the water heater just won't work right, but a motor could be quite damaged, as could the generator. They require that the two legs of the input be 100% synchronized. You could power some 120 volt loads off one leg from one generator and some off the other leg and generator, but you couldn't really do it safely. It's against code for anything inside of a panel to be powered from two independent sources, for one thing.

Brian
MrWizard
Moderator
Mar 09, 2015
Bad idea
Shared neutral..on out of phase wave forms
Could fry both generators
Buy one generator that does 230v
valhalla360
Navigator
Mar 09, 2015
No this is a bad idea. Don't do it.

The Yamaha/Honda units can be paired because they are inverter based and specifically designed to match line frequency...but even they don't do 220v.
kaydeejay
Explorer
Mar 09, 2015
All lights, appliances etc that run on 120 volts (ie one leg) would be OK but anything on 240 volts would not as the sources would not be synchronized as far as waveform was concerned. They would be "out of phase".
Stove, water heater, well pump, A/C etc. would need to be isolated.
Personally I don't think it's a "good idea".

Forum Discussion

2 generators simultaneously for backup power

About Technical Issues

Related Content

Generator noise reduction

Generator operation

generator for home backup

backup monitor

Backup camera failure