Thread: Question on wiring batteries, graphs and trolling motors

Originally Posted by Jamesdean

Something I found rather interesting, this thing, (boat), has no kill switch in the wiring at all...??? Donno...

Is there a provision for it up there at the selector?

Possibly it was stand alone wired back from the motor

My Dad had an old, old Scott Attwater that caught fire once on the back of the boat going down the river. He unclamped it from the transom, and deposited it directly toward the river bottom. Dad popped His palms together a couple of times and said, "Problem solved. Now lets dunk Indians back to the house". (Our paddles had an old Indian chief on 'em, Feather Brand, me thinks). I guess you could say Dad was the "Kill Switch".

Originally Posted by TheGrandPoohBah

Is there a provision for it up there at the selector?

As of right now, I haven't found any kill switches except the ignition switch. Maybe up under the lip of a hatch I haven't looked under yet. Still compilating if I'm going to do everything that needs done, (cap off restoration, transom, stringers, foam, bottom deck, and deck covering), or have it done for me. Cheaper if I do it, done faster if a shop does it...Momma wants a shop to do it, easier on my body, but either way, have to wait for the Camp Lejune settlement. At least they've started making offers of settlement amounts without litigation. I think 3 have settled with 2 being paid already and 23 more offers in the mail as of Tues. this week. Been 1 months since my claims Dad, Mom, and myself went to the Navy (JAG), so who knows how long till I get mine. But, On what I read, it will be a sizable chunk...

You probably won't find one, it isn't really common to have a shutoff on the outboard wiring. There's really nothing on those motors that draws power with the key off so there is no need. If you start adding electronics to that battery, many people will add a small manual reset circuit breaker before the fuse panel, or wire the switch panel so that there is a master on/off switch.

Depending on the size of the graphs you can often get away with running one or two on the cranking battery. As you mentioned it is not advisable to run them on the trolling batteries due to interference.

That said with lithiums becoming more affordable and graphs getting bigger (requiring more power), it makes a lot of sense to add a dedicated electronics battery, when they don't weigh much at all and have a pretty small footprint. Once you add all the stuff in a modern boat together (graphs, bilge/livewell pumps, lights, etc.), it can be pretty hard on the cranking battery, and the charging system on those older outboards is pretty much a trickle running wide open, and basically nothing at idle so they have a hard time keeping up. One good thing about these new four strokes is that most of them have a full size alternator that can crank out the juice even at idle speed.

Originally Posted by Atimm693

You probably won't find one, it isn't really common to have a shutoff on the outboard wiring. There's really nothing on those motors that draws power with the key off so there is no need. If you start adding electronics to that battery, many people will add a small manual reset circuit breaker before the fuse panel, or wire the switch panel so that there is a master on/off switch.

Depending on the size of the graphs you can often get away with running one or two on the cranking battery. As you mentioned it is not advisable to run them on the trolling batteries due to interference.

That said with lithiums becoming more affordable and graphs getting bigger (requiring more power), it makes a lot of sense to add a dedicated electronics battery, when they don't weigh much at all and have a pretty small footprint. Once you add all the stuff in a modern boat together (graphs, bilge/livewell pumps, lights, etc.), it can be pretty hard on the cranking battery, and the charging system on those older outboards is pretty much a trickle running wide open, and basically nothing at idle so they have a hard time keeping up. One good thing about these new four strokes is that most of them have a full size alternator that can crank out the juice even at idle speed.

Funny you should mention four-stroke outboards. It currently has a 1973 Evinrude 65hp on it now. The prev. owner had said he had purchased a pontoon from a friend, and swapped the motors. What with Evinrude closing up shop and the available parts dwindling, and their price going up, I've been looking at the four strokes. Haven't decided yet, but the two that currently has my attention are Yamaha and Tohatsu both 75 hp.

Don’t put anything on the trolling motor batteries but the trolling motor. Circuit breaker of appropriate size along with correct size wiring.
You may be ok running electronics off your starting battery but if you have available space try to run a dedicated battery for them.
Good luck.


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Thank you Chuck. I'm thinking of having a total of four batteries in all. 1 for the outboard dedicated only, 1 for the house battery, graphs, lights, bilge and aerators, the 2 for the trolling motors. Without taking the aluminum fuel tank out, which just might happen anyway, there's only enough room in that hatch for 2 batteries. The trolling motor batteries would need to go forward, maybe extend the front deck back enough to cover them...Still in the planning stage yet. But needing the four batteries, Lithium defiantly...