12 volt or 24 volt trolling motor

I'm thinking about upgrading my motorguide brute 24 volt 55 lb thrust trolling motor since i've had to repair it several times, can't get parts anymore, and am concerned about it going out again while on the water. The motor is 15 years old and parts aren't available anymore.

The newer 12 volt motors have just about the same thrust as my old motorguide. I found one that has 54 lbs of thrust with a 12 volt motor. If I reconfigure my wiring to accommodate the new voltage, it seems to me since i'll be running the batteries in parallel instead of of series that the current through the boat wiring will be cut in half and should work without problems and seems also that my circuit breaker should be able to handle the current going through the system too.

Should I be ok here or should I go with the 24 volt motor? There's a big difference in price but I don't wanna run into problems down the road. thanks

You have it backwards. At 24V your current is half what it will be at 12V, so you need bigger wire and a larger breaker for a 12V motor if they have similar thrust.

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Originally Posted by CatFan

You have it backwards. At 24V your current is half what it will be at 12V, so you need bigger wire and a larger breaker for a 12V motor if they have similar thrust.

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I know what you're saying, but if I wire the batteries in parallel instead of series, half the current should go down one set of wires and the other half should go down the other set of wires. I have 4 wires that go from the batteries to the front of the boat.

Sounds like you have one of the older 12/24 motors where the switching to 24 volts is done at the TM's switch. Either way you go with the new one you will have a few simple changes to make as you will only need 2 wires. A 24V system will give you longer trolling time but then running 2 batteries in parallel for a 12V motor will too.

I'd skip the parallel battery hookup in favor of a switchable arrangement that only draws on one battery at a time. Batteries degrade at different rates, due to age, manufacturer, chemistry, group, etc. If you gang two or more batteries in parallel, they will attempt to maintain a constant voltage across the whole set. That means the strongest one will lose voltage "recharging" the weaker one(s). By hooking up to one battery at a time, you get its full load. When the first one is depleted, switch (manually) to the next battery & use everything it has.