Conecting 2 separate systems to get 220v

[jabookoo]

Hello There!
I have been living 100% off the grid on battteries and back up generator for 14 years now. I have a 48v battery bank with a sw4024 trace inverter that gives me 120v. I also have a 2nd exact same set up but the batteries are a different brand, age and size but still a 48v bank producing 120v.The 2nd system is currently not in use and my issue is I can't stack the 2 inverters due to the different battery styles. Can I run 120v line to one side of the main breaker box and the other 120v from the 2nd inverter to the othere side to give me 240v. If not how can I combine 2 totally separate systems into one to get 220v?

[foo1bar]

Hello There!
I have been living 100% off the grid on battteries and back up generator for 14 years now. I have a 48v battery bank with a sw4024 trace inverter that gives me 120v. I also have a 2nd exact same set up but the batteries are a different brand, age and size but still a 48v bank producing 120v.The 2nd system is currently not in use and my issue is I can't stack the 2 inverters due to the different battery styles. Can I run 120v line to one side of the main breaker box and the other 120v from the 2nd inverter to the othere side to give me 240v. If not how can I combine 2 totally separate systems into one to get 220v?

Sounds like a bad idea.

Is there any synchronization between the two?
If not, you could have anywhere from 0V to 240V AC.
It could even be 0V one minute (because they hapen to be perfectly in phase) and the next minute it could be completely opposite phasing and you'd have 240V.
How you ask? If one is 59.99Hz, and the other is 60.00Hz, every 100 seconds they'll have their peaks at the same time, and 50 seconds after that, their peaks will be exactly opposite.

I think that you're better off doing two separate systems - one doing half the house, the other doing the other half and not trying to have any appliance/circuit that crosses the two. But you can do some searches on your specific inverter, seeing if there's any way to synchronize the two.

[Mike90250]

To create 240VAC, you have to insure the 2 inverters are 180° out of sync.
Generally, the inverters need to be of the same brand, and have a sync cable connected to them to accomplish this. That's the only way I know how to do it safely.

[jflorey2]

I have been living 100% off the grid on battteries and back up generator for 14 years now. I have a 48v battery bank with a sw4024 trace inverter that gives me 120v. I also have a 2nd exact same set up but the batteries are a different brand, age and size but still a 48v bank producing 120v.The 2nd system is currently not in use and my issue is I can't stack the 2 inverters due to the different battery styles. Can I run 120v line to one side of the main breaker box and the other 120v from the 2nd inverter to the othere side to give me 240v. If not how can I combine 2 totally separate systems into one to get 220v?

Short answer - no.

Why can't you stack? Although the DC grounds need to be common on the two SW inverters, as far as I know the battery + does not need to be. You'll run into problems balancing the two systems, but it should still work at a basic level.