More info on my onboard charger. I recently had it die (lemon unit, it overheated, new one runs much cooler) and the supplier replaced it. This gave me a bit more time to test the comparison between the Schumacher and Soneil (onboard) chargers. The conclusion is that the Soneil is WAY more efficient!
Average overnight kWh used:
Schumacher - .95
Soneil - .35
Thats right, the Soneil uses 1/3rd the power to recharge my battery! In the bulk charge stage, the Schumacher (10A charge) pulls just under 200W and the Soneil (7A charge) pulls just over 100W. In the final stage of charge (just keeping the battery topped off), the Soneil pulls only 3-5W where the Schumacher pulls 23W constantly. So, I'm becomming a huge fan of the Soneil chargers and would highly recommend them to others. They've also been working great on my
electric lawn mower.