trolling motor wiring

[gregtobin]

I am shopping for a trolling motor in the 60-70 pound range and would like to run it off two batteries that I will store in a space in the bow. For simplicity, I plan to continue running all other accessories (only lights, bilge, horn now, but I will add a fishfinder) off the starting battery.

I have an 18 foot boat so I would need some pretty long cables to run from the outboard up to the new dual batteries if I wanted to charge off the alternator of my '74 Merc 1150. I am thinking that I could probably troll for a few hours with fully charged batteries and just charge them at home before leaving.

Does anyone know how long these batteries (deep cycle marine wet cells with about 550 CCA each) would last? I don't plan on water skiing with the trolling motor so I figure that I'll just be using partial power....

Should I plan on running wires to the alternator or is the alt output not going to make a huge difference in charging the batteries anyway? I'm not even sure of the output of my alternator.

Thanks
Greg

 

[jtexas]

Re: trolling motor wiring

You should get a pretty good days' use out of 'em without charging on the water. Unless your honey holes are all separated by miles & miles of open water, I'm not sure you'll make a dent in 'em. Note that the biggest (okay, one of the biggest) causes of boat battery failure is shock & vibration, and in the bow they'll take a pounding. Also don't underestimate the weight & balance impact of two 12V batteries.

 

[gregtobin]

Re: trolling motor wiring

Do you think it would be better to put the two batteries in the transom for better weight distribution and than run wires to the trolling motor in the bow?

 

[jtexas]

Re: trolling motor wiring

Most bass boats have all the batteries in the stern - you'll want heavy gauge wires. mine are just a little forward of the helm cause I had a space for 'em there (meaning, I built a compartment for 'em). But I just have a vintage 1980 trihull, 15ft, stead of one a them fancy performance hulls.

ok, I just noticed you said you're planning to troll...whereas most (if not all) the fishing done round here, trolling motors are used for positioning, holding against the wind, that sorta thing, if we do any actual trolling, we use the main engine - if you're on it (the T/M) constantly at high power, might want to do some calculating as to your expected run time.........a battery's *Reserve Capacity* is the number of minutes it takes to completely discharge it at a constant 25 amps. Not sure about your trolling motor, maybe 30, 35? check with the manufacturer. So deepcycles with an RC = 210 minutes, at 30 amps that's 175 minutes (210 x 25 ? 35). But performance will really start to suffer after just half that time. of course that's theoretical, actual performance will vary.

what kind of boat?

 

[Barnacle_Bill]

Re: trolling motor wiring

You need to run #6 wire and use a 50 amp circuit breaker. Forget about trying to keep them charged with the motor. It ain't going to happen unless all you do is run up and down the lake at WOT all day. Recharge immediatley after every use to prolong battery life. Look into installing an onboard charger. They are the greatest thing since sliced bread. You get home, plug it in, and forget it until time to go again.