generator sizing

[Jerry Pierson]

What is the minimum size generator I can use as backup?
Have 750 watts of PV and a 12v battery bank using 4 -Surrette S-550 6v batteries.
Inverter is a Magnum 2000. presently using a 5700w Mitsubishi

[Rob Beckers]

Jerry, there's no real minimum as such. However, when the generator is running the inverter will switch to charge mode, and all your loads will have to be carried by the generator.

So, for your 2kW inverter that means the generator should be able to handle 2kW if you foresee using your inverter to that point. The Magnum inverter can be set to limit its draw from the generator (for charging); For example, if you set it to 16A (that's about 2kW at 120 Volt AC) it will monitor current going to your loads and to the batteries, such that it will back off on the battery charging to keep the total at or below 16A.

-RoB-

[Mark Faller]

Thanks for the explanation Rob. I was wondering about the same thing as Jerry.