I am designing a system for emergency backup power and I have some questions. This is a 120/240 single phase system in the US. I am planning to use a battery bank plus diesel generator to meet peak daytime demands and to charge the batteries, and the battery bank alone to power low demand periods and overnight. I would like the system to power both 120V legs of my main panel (120/240 split phase), and the system will be isolated from the grid by a manual transfer switch. Some design needs:
— generator is a 10kw diesel generator supplying 120/240 single phase power, maximum 52A supply.
— I would like to over-spec the system to accept up to ~100A of generator current in case I switch to a larger generator down the road.
— I currently use around 12kW of non-peak power per day, though this could be mitigated during an emergency.
My questions:
1. I believe I will need either 2 Multiplus 120V units or 2 Quattro 120V units linked for split phase at a minimum to achieve this?
2, I am looking at the 120V / 5000 units, because these can accept up to 100A of AC input.
3. When powering these with a 120/240 generator, would I supply each unit with opposite 120V legs as their AC inputs? I’m assuming this would be required to keep the generator balanced.
4. If I use the Quattro units, can I connect grid power as my second AC input in order to charge the batteries when the grid is up and running? Even though the grid power is on the other side of a transfer switch? Will this be ok from a safety standpoint, there won’t be any AC current fed back onto the grid through the AC input if the grid power is down and the generator is running?
Thanks for any helpful advice.
