RickBullotta
E*POWAH Elite World Champion
I have a separate battery box in my 4Wd, rather than a 2nd battery. The box can charge from a cigar socket, anderson plug or AC power and has 12v output and a 300 watt inverter. This is more than enough to run my 6001 charger and even a normal deep cycle can give me a full charge without dipping below the recommended 50% use. My box has a 120aH LiFe4PO in it so I can get two full charges. I like that it's a completely separate unit to the vehicle. Mostly it just slow(er) charges off a socket although if I'm in one place for a few days I'll hook it up to some solar.
I also have a 200aH LiFE4Po in my camper which can run a 600 watt inverter. So technically I could get 5 full charges off that one, although I've never tested it with the bike. That one's got 300 watts of solar charging as well as from the vehicle and AC. Getting it below 50% takes some effort.
It would still be nice to have a 12V charger for the Shimano batteries. So much power is lost through the inverters and power supply. And it's be nice to be able to top up a battery without having to carry a 30kg pack in the car.
Gordon
I highly doubt that your cigar socket has wiring/fusing for a 30 watt load though.