6300 is a ferroresonant converter, very poor voltage regulation, single stage, the best recommendation is to go to
Industrial Communication Solutions - B&B Electronics (not sure about the trailing s on converters) and order a good 3-stage, These include the following
Progressive Dynamics 9200 sereis I'd go with a 35-40 amp model in all cases
Progressive Dynamics 9100 with optional charge wizard (Same as above)
IOTA with IQ-4
Xantrex True Charge
and a long, long list of others.