Genuinedealz.com has a wiring calculator on its site. You enter wiring size, run,volts,amps and it will tell you the voltage drop. This seems to me to be the big issue. Is there any power left when it arrives at the motor?
I also find it interesting that MinnKota told me I had to go from their supplied #10 wire to #6 if I extended the wire and yet the largest plug they sell is for #8!!!
I guess I'm going to put the batteries up front and it won't be a problem.