Jump off the trolling motor battery that has 12 volts before it makes the jump to 24 or 36 volts. On mine it's the inside(far left) battery. I haven't had to do it, but I always know which one I can jumpstart from incase I run into that very situation. A good set of cables is all that's needed. I will say I have done the very thing your asking about twice with a heavy duty jump box my wife got on QVC. Wife says they sell them all the time on there. The brand is Xantrex. Iv'e jumped lawn mowers, boat motors & Chevy trucks with it.