Trolling motor wire

gee cee

Cadet
Joined
Oct 5, 2009
Messages
13
The used boat I bought, didn't come with trollling motor,but is wired for one. The wire is#10, is the wire size enough? the lenght of the wire is 22 feet. the trolling motor is a 12 volt motorguide 56#.

Are the AGM or Optima batteries worth the extra cost? I have never had a real problem with lead acid batteries, if well maintained. The main problem is with the boat I have, you have to remove them to check the water level. so when battery replacement time comes, I was going to replace them with AGM or Optima


Thanks
 

ajgraz

Lieutenant Commander
Joined
Mar 1, 2010
Messages
1,858
Re: Trolling motor wire

You're probably going to draw something like 40A max.

Is that 22 feet of hot (red) and 22 feet of ground (black), or 22 feet of hot (red) and then grounding to something, like maybe a ground terminal block (with some nice fat wire leading back to the battery), right near the motor?

If the former, you're dropping nearly 2V in a 12V system, that's too much. You'd want 8AWG or even 6AWG for that kind of distance.
If the latter, you're dropping closer to 1V, much more acceptable, but still too much for my comfort.
 

gee cee

Cadet
Joined
Oct 5, 2009
Messages
13
Re: Trolling motor wire

both red and black are 22 feet long or 22 feet from the battery to trolling motor receptable,

If I go to a 24 volt trolling motor what be the right wire
ohm's law as voltage goes up amperes drops correct?

appreciate the input
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
Re: Trolling motor wire

While your understanding of Ohms law is valid, it only applies if all things except voltage remain the same. 24 volt motors start at about 70# of thrust and it takes more current to make thrust so that comparison is not valid. I don't have numbers for MotorGuide but a 70# Minnkota will draw 42 amps worst case. A 55# 12 volt Minnkota draws 50 amps worst case. So spending much more money for a 24 volt motor in hopes of not having to change a few bucks worth of wire just doesn't make sense. It makes even less sense to put a 70# motor on a boat that doesn't need it.

As for batteries, in my view it is a waste to spend big bucks for a trolling motor battery when a group 27 or 29 deep cycle for well under a hundred bucks will do the same job as the so called "hi-tech" batteries. A group 27 deep cycle at my local farm store is regularly priced at $75 and can be had on sale for $69 and it has higher reserve capacity than the same size AGM.
 

tahoejag

Petty Officer 1st Class
Joined
Jul 4, 2009
Messages
229
Re: Trolling motor wire

Running a MK #80 24v system that moves a 3000 to 3600 lb boat (depending on load) pretty good. Would be nice to have the #101 thrust motor though...:D, but the 80 does just fine! Boat was originally wired for 12v trolling motor with I believe 8AWG wire (if not 10AWG, not sure). Its a 20 ft run. I re-wired to a 6AWG knowing that my motor I believe is 56 amp draw max....or around there. That way I'm on the safe side and no worrys about wire gauge being too small. As recommended to me, I would at least use 8 AWG...being a long run and 24v system.

As for batteries....2 interstate srm 29's (210 min RC), more than plenty enough battery! My cost was $220 for two OTD in 2010, going on fourth season their still in "like new" conditon. I agree with Silvertip that a good group 27 or 29 will do just fine at a lower cost than so called "hi tech" ones. Also I bet that the warranties are pretty close in comparison to each other....JMO.
 

saumon

Lieutenant
Joined
Aug 2, 2004
Messages
1,452
Re: Trolling motor wire

That's what they said in my Minnkota (PD55 12V) owners manual. Use the provided 4ft of 10 ga. or, if you extend it, use 6 ga.
 
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