Off grid, running generator to charge batteries

Hi Towpro,

I would not have started the generator at 87% state of charge. Best bang for the buck is from 50% to 85% (or perhaps 90% with AGM). At 85% charging is limited to about 12.5 amps per 100 amp-hours of storage.

Fastest charging is to come close to the gassing voltage but NOT exceed it. Temperature compensating charging is the way to go.

If an AGM bank is accepting 0.5 amps per 100 amps of storage capacity it is de facto fully charged.