I took mine apart to see what makes it tick. It is basically a permanent
magnet motor with "speed coils" used to limit the amount of power
getting to the motor to control speed. At the highest setting the
battery is connected directly to the motor. If you spin the motor (like
with an electric drill, the voltage at its terminals increases with
speed. The question now is "can it be spun fast enough under sail power
to get high enough output to charge the battery?"

BS

Bob S wrote:
Both Minnkota and Motor Guide produce electric trolling motors big
enough to use as auxiliaries on small sailboats. Has anyone tried
running these motors as generators to charge the on-board batteries?
Does anyone know the motor configuration (permanent magnet, shunt wound,
series wound)?

BS