Trolling motor batteries

[2 lund bums]

Hi
I bought an 18' ft pontoon last year and it has a 70hp motor on it, but I would like to put a trolling motor on it and it could then be used to move the boat if the motor would die. I figure on about 80 lbs of thrust and the websites say I need 36 volts. Does this mean I need to have 3 12 volt batteries? I'm new to this and have no clue. I was also advised by someone that a bow mount would probably work the best. Does this need to be welded to the pontoon?

Thanks
Margie

 

[tashasdaddy]

Re: Trolling motor batteries

the motor will come with a retractable mounting bracket, that you mount to the front deck, preferable so that when it is down it in the center of the bow. if concerned, you can put a plate under the deck and just thru bolt it. will be fine. yes, you will need 3 deep cycle batteries. wiring, circuit breaker.

 

[tashasdaddy]

Re: Trolling motor batteries

if you are going to use this as and emergency, and not fish or troll. consider a 6 hp outboard. overall probably cheaper. hang a mount off the stearn.

 

[James Tobias]

Re: Trolling motor batteries

buddy of mine has 20ft pontoon with 36 lb troll and runs his on a exide 12v deep cycle 75amp hrs 100 reserve cap bought at wal-mart no problem

 

[jtexas]

Re: Trolling motor batteries

Gotta agree with tashasdad if this is strictly as an alternative means of propulsion - there's no weight penalty by the time you add 3 batteries, plus which it'll be better for trolling if you do a lot of trolling. My experience, "electric trolling motor" is a misnomer since around here it's not used for trolling, just for positioning the boat.

To answer your questions, yes a 36-volt motor requires 3 12-volt marine deepcyle batteries (preferably matched as to capacity) wired in series (socket to batt1(+), batt1(-) to batt2(+), batt2(-) to batt3(+), batt3(-) to socket). Best put a circuit breaker in there, I'd say at least 40a. A socket that accepts 24/36 or 12/24/36 motors will give you more flexibility at a little bit higher cost. Use heavy gauge wiring, at least 10ga maybe 8.

I would agree a bow mount would work best for ya. Foot control or hand control is up to you - if you'll usually be standing while operating it get the hand control & add a foot-control on/off or momentary switch.

Welding is optional: bow mounts are bolted to the deck with "isolater bolts", a bolt with a big rubber grommet that expands as you turn the bolt, so you don't need access to the underside of the deck.

not disputing your buddy's experience or anything James, but I use a 36lber with my 15ft fiberglass boat - works great but in really high winds I sometimes wish for more power.

shaft length is also an important measurement, distance from deck to waterline plus a couple feet ought to do it. that sound about right, guys?