generator backup

mulcor

Hi, new to this forum so sorry if this is covered somewhere. I just installed a small solar power system at my cottage. I have a 100w PV panel charging 4 100ah 12v batteries. I know I need more panels but not in the budget this year. I'd like to charge my batteries with a generator when reguired. I have a honda em1800 with a 8.3amp battery charger on it. My question is am I best to run the generator charger directly to the batteries or through the charge controller, or is it better to charge the batteries using an automotive battery cherger plugged into the A/C from the genny?

westbranch

the built in chargers are very inefficient , get an auto charger at least and it will work far better

mulcor

That's what I figured, should connect the auto charger through the charge controller or direct to the battery?

BB.

Direct to the battery.... Your Honda will support around a 25 amp charger, at least, and possibly up to 40-45 amps @ 12 volts--But that depends on the design of the battery chargers (many battery chargers are designed very cheaply--And that makes it very hard on the genset to run them).

Your four batteries want around ~40 amps @ 14.4 volts or so to charge... You can run from 20 to around 52 amps (5% to 13% of battery 20 Hour Rated capacity) of charging into all four. Or, break them into single batteries and charge with a smaller charger. With the genset, you really want to run it around 50% to 80% of rated output for best fuel economy. If you run at 25% or less, you will be wasting a bunch of fuel (~2x fuel or more).

-Bill

mulcor

Ok great, thanks for the replies.