I would suggest the use of a good quality RV battery. I have the 12v Minnkota
and have used the same battery for the last 4 years, and it still holds the
same charge. You need to use a battery that can be constantly recharged, and
the use of a solar trickle charger is another thing I'd invest in if I were
you. Don't go cheap on that either, you'll only regret it later. The cheapest
I'd go with is the $70 model. That'll give you enough amps into the battery if
you aren't using the battery constantly and for all the accessories. Use a
second battery and a third for the accessories like the fish finder and the
radio. There's a really nice, larger solar panel available at Fry's (
outpost.com ) that, if you have the room onboard, you'll not need to worry at
all about power except at night.