My Dad bought a motorguide brute 6700 series 24 volt trolling motor. I can get it to run off of one battery but not two? I wired it for straight 24 volt because it says 24 volt on top of the motor. Any ideas, I checked and am getting like 42 volts at the plug when I hook them together and 32 when only one battery is hooked up - seems like a lot to me?