How much stuff can you run off a trolling motor battery?

[Coastal Rick]

Of course there is no exact answer because it depends on so many variables. But let's see if there is a range or good estimate, ok?

I have a 14ft aluminum Western with 20hp Merc on the back. Just your basic open design with three bench seats and a little console. Up till this point I've only used a minnkota endura 30 transom mount on the battery. But I have a new humminbird 570 coming soon, and eventually would like to set up nav lights too. Who knows, maybe a bilge pump would be nice as well.

My battery is an Everstart 24DC-6 marine trolling battery (I think I got it at Walmart) with 75 amp hours, reserve capacity of 100. Mainly I'm thinking of using the minnkota to troll for trout, and putt around for bass, and keep on top of rock piles for bottomfishing in the bay. I'd have the 570 running the whole time. The lights would be used infrequently.

Would that be too much stuff to run off a single battery? About how many hours do you think I could troll around (fairly slowly) with that set up? Thanks everyone!

 

[jtexas]

Re: How much stuff can you run off a trolling motor battery?

The battery will easily power all that stuff, but........

If that fishfinder drew any less current, it'd be charging the battery...seriously it's probably 100 milliamps or so (1/10 of one amp). Put it on your cranking battery to avoid electrical noise showing up on the screen.

Myself, I run only the trolling motor on the trolling battery.

All my accessories (bilge, nav/anchor light, livewell intake and pumpout, horn, sonar) on the cranking batt. The 6-amp alternator on my outboard has no problem keeping it charged...I check it every time out, it never needs recharging.

Only exception is when I bring along the bait tank; I generally leave that pump running 100% of the time so it runs off the trolling battery.

 

[Silvertip]

Re: How much stuff can you run off a trolling motor battery?

I agree that on a boat with a small engine that can easily be rope started there is no reason to power a small number of accessories with the trolling motor battery. Use that battery to power the troller since it is drawing about 30 amps and you need all the run time it can provide. There is no solid answer to this question. Reserve minutes (100 in your case) is based on a current draw (generally) of 23 amps. So IF (note the IF) you run your motor wide open for one hour it would draw roughly 30 amps from the battery. Therefore if the battery was fully charged and in good condition, it would deliver 23 amps for 100 minutes or roughly four hours of run tiime. Since your motor draws 30 amps it would likely run the motor for about 3 hours before it could no longer deliver 23 amps.

 

[arks]

Re: How much stuff can you run off a trolling motor battery?

Silvertip has correctly shown that yes, you can indeed do it- mathmatically. But it assumes the battery has a 100% charge and is in tip-top condition. When you add accessories like a bilge pump and nav lights, power consumption estimates become much more difficult to determine because they typically don't run all the time.
IMO it's preferable to have a battery with significant reserve capacity.
On my 14 footer I use a small lawn tractor battery for starting and accessories, and have another group 31 battery (990 CCA) mounted forward just for the trolling motor. I consider it just right for my needs, and not overkill.

 

[Coastal Rick]

Re: How much stuff can you run off a trolling motor battery?

It sure is amazing how knowledgeable folks are on here, and willing to share to boot. I hadn't considered many of those things so I'm way ahead already. The battery was purchased a little while back for a small inflatable with the trolling motor, so there wasn't much need for lots of capacity. I've moved up to the 14' a couple of months ago. I don't have a cranking battery - pull start only 20hp merc.

It makes sense to have the trolling motor on the Everstart, and then possibly a smaller lawn tractor (or similar) running the finder and lights and so on. How well do you think that little battery would work - any special suggestions on that?

I'm just trying to keep things simple, and appreciate all the insights.