Choosing a trolling motor battery

Trolling motors, Fish Finders, GPS, Batteries, anything Electrical, post it here.
JNG
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Choosing a trolling motor battery

Post by JNG »

I run two 6 volt Interstate Extreme Cycle GC2-ECL-UTL batteries wired in series. I get 12 volts this way and 225 amp hours @ 20hr and 447 reserve capacity minutes @ 25 amps. Weight is 62# each, which is the same for any group 29 12 volt dual purpose battery. You cannot EASILY buy true 12 volt deep cycle batteries anymore. All the common 'deep cycle' batteries that you see for sale at Walmart, Autozone, Napa, etc are actually dual purpose batteries. They don't have the capacity nor the life of a true deep cycle. For example-

Autozone Duralast Marine 29DP-DL
63.3#, 106 amp hours at an unspecified rate, 210 reserve capacity minutes at an unspecified rate.

Two of these wired in parallel gives you 126.6#, 212 amp hours, 410 reserve capacity minutes.

You also get shorter life, you better not discharge the batteries below about 75% capacity or charging capacity and battery life suffer greatly, and you also get less capacity. Golf cart batteries are true deep cycle batts and are designed to withstand deep discharges, have great capacity, and still give decent life. The only problem is that they are expensive. Roughly $150 each for mine. Compare to the Duralast at roughly $95 each.

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bcbouy
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Choosing a trolling motor battery

Post by bcbouy »

i run 2 deka agm group 31's in my boat and 2 in my camper.however they weren't cheap.almost 2 k for the lot.these are deep cycle ,not starters.my boat starter is a quicksilver starter/deep that came with the boat.
if all else fails....stop using all else

Ryzen
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Choosing a trolling motor battery

Post by Ryzen »

Giving the amount of time that has passed since the initial post on this thread, I guess you've found the battery you need. Let us know what battery did you choose, please. Boat weight is the most important consideration to take into account when choosing a trolling motor. A beginning rule of thumb is that you want a minimum of 2 lbs of thrust for every 100 lbs. For example, if you have a 3000lb boat, fully loaded, then you'll need 60 lbs of thrust. Speaking about batteries, at https://batterytools.net/ you can find a lot of valuable information about batteries.

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onthewater102
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Choosing a trolling motor battery

Post by onthewater102 »

My how things change in 4 years.

Lithium batteries are down to less than $300 for a 50 amp-hour battery...given the weight savings alone they're attractive - ditching the issues of memory and the need for proper trickle charging to avoid sulfating is awesome...faster charge times, no capacity penalties for partial charging and a much more consistent power output curve???

I will never be buying another lead-acid or AGM trolling motor battery again.
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Rebelwork
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Choosing a trolling motor battery

Post by Rebelwork »

I only run an aluminum boat but about 4-5 hours 3 days a week. I bought 2 Menards FVP batteries for $90 bucks each. I had two trolling motors front and back. Running one to get close and trolling the front when I got there. I eventually disconnected one and run. I run a stereo full time, charger o the phone and bilge. No problems...

If next spring after being in the garage there dead, I'll spend $200 on fresh batteries.,

CRS
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Choosing a trolling motor battery

Post by CRS »

onthewater102 wrote: 03 Aug 2021, 16:36 My how things change in 4 years.

Lithium batteries are down to less than $300 for a 50 amp-hour battery...given the weight savings alone they're attractive - ditching the issues of memory and the need for proper trickle charging to avoid sulfating is awesome...faster charge times, no capacity penalties for partial charging and a much more consistent power output curve???

I will never be buying another lead-acid or AGM trolling motor battery again.
Agree 100%

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LDUBS
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Choosing a trolling motor battery

Post by LDUBS »

Be nice to see the prices drop. I'm thinking by the time I need to replace my battery, the lithium 100ah will be at $150!
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onthewater102
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Choosing a trolling motor battery

Post by onthewater102 »

I put my $$$ where my mouth is (or, erm, fingers are? modern times are so confusing adapting old sayings.)

Either way - I ordered a 50amp Ampere Time LiFePO4 from Amazon after reading more reviews of different brands than I can remember. They seemed to consistently get positive comments from people using them in solar home energy systems FWIW.

We'll see how it stacks up as a trolling motor battery.

From what I read on lead-acid type battery research reports, we only get use of about 50% of a lead-acid battery's stated capacity before the voltage has dropped low enough that it will start adversely affecting the performance (digital circuits especially). If that's true then I should be getting comparable use time from the 50amp lithium as I was with my size 29 SLA's previously. Hopefully that's true.

What is definitely true out of the box is that it weighs a bit less than 15lbs instead of 61lbs which will help a lot in a little tin boat, not to mention it's so much smaller that I can tuck it in a recess at the back of the compartment which previously was filled by the big SLA battery.
I have a marriage license and a fishing license, but I only carry one in my wallet.

1985 Bass Tracker III

For Sale - Custom Hand Tied Jigs, Bladed Jigs,Custom Rods

2002 Alumacraft 1436LT (SOLD)

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LDUBS
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Choosing a trolling motor battery

Post by LDUBS »

The weight savings is huge. I have a grp 31 battery that is about 65#. All that weight I keep adding to the boat really starts to add up.
Have Rod - Will Fish

MrGiggles
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Choosing a trolling motor battery

Post by MrGiggles »

onthewater102 wrote: 12 Aug 2021, 11:34
From what I read on lead-acid type battery research reports, we only get use of about 50% of a lead-acid battery's stated capacity before the voltage has dropped low enough that it will start adversely affecting the performance (digital circuits especially). If that's true then I should be getting comparable use time from the 50amp lithium as I was with my size 29 SLA's previously. Hopefully that's true.

I have read the same things, but most seem to agree that you can discharge a lead acid battery to 70-80%. Those group 29s were probably ~100ah, so that would give you 70-80ah of usable capacity. Most fisherman wouldn't use that much in a typical outing with a 24-36 volt motor, multi day camping trips or tournaments, maybe.

The big difference there being what you said, that lead acids will gradually lose voltage. Lithiums will generally stay pretty flat until they quit altogether.

I would like to make the upgrade, but my current batteries still have a couple years left. Hopefully by then lithiums will have come down in price even more. Right now they are getting close to penciling out for me, but not quite there.