# Battery for trolling motor performance



## exide9922 (Aug 9, 2010)

I'm new to boating and trolling motors, had a question on the battery. My motor really started to slow down on my battery the other day, figured it was almost dead (had been on the water 4-5 hours) so I switched to my spare for the first time. Motor started going "full" speed again. later that night I was curious how low the first battery was so i hooked it up to the charger and it was around 45% Will a motor slow down when the battery gets lower like that? or should it still be running good until it's empty?


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## Cajunsaugeye (Apr 9, 2013)

It'll start slowing down little by little.


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## leeabu (Apr 10, 2004)

exide9922 said:


> I'm new to boating and trolling motors, had a question on the battery. My motor really started to slow down on my battery the other day, figured it was almost dead (had been on the water 4-5 hours) so I switched to my spare for the first time. Motor started going "full" speed again. later that night I was curious how low the first battery was so i hooked it up to the charger and it was around 45% Will a motor slow down when the battery gets lower like that? or should it still be running good until it's empty?


Motor will slow down because the voltage will drop.


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## exide9922 (Aug 9, 2010)

leeabu said:


> Motor will slow down because the voltage will drop.


well that explains it! thanks. I guess I just figured it would run better with that much left in it


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## Bad Bub (Jan 17, 2006)

That's actually "very discharged" for a battery with only 4-5 hours on it if it was fully charged at the start of the trip. The only way I would consider that "normal", is if you were running at a high speed almost constantly. I'd recommend checking your water levels, and making sure your battery is taking a full charge. It may be on its way out...


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## exide9922 (Aug 9, 2010)

Bad Bub said:


> That's actually "very discharged" for a battery with only 4-5 hours on it if it was fully charged at the start of the trip. The only way I would consider that "normal", is if you were running at a high speed almost constantly. I'd recommend checking your water levels, and making sure your battery is taking a full charge. It may be on its way out...


it's a new battery. yeah we were going full speed most of the day. went from one end of nimi to the other and all the way back, plus checked out some other areas. was my first time on the water at nimisila and was exploring. wind wasnt helping either.


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## Cajunsaugeye (Apr 9, 2013)

Full speed will drain your battery QUICKLY.Definitely in 4-5 hrs and definitely if its a larger thrust trolling motor and a smaller battery.What size battery? I'm guessing a smaller 27 size.If so,you're doing GOOD getting 4-5 hrs at full bore w it.


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## fastwater (Apr 1, 2014)

Just another thought...

...might have been a new battery but do you know if it had a 100% charge at onset of trip?

Assuming this is a deep cycle battery, make sure to charge battery to 100% ASAP *after each trip* when you get home. Your battery 'life' will last much longer as in the time frame it will be before you have to buy another battery


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## bdawg (Apr 14, 2009)

First off, don't forget the oars!!! They will always work as long as your arms don't fall off! They've saved me a couple of times.

Second, check the water level in the battery. I got a new one, used it 2 times before the battery died on me on the 2nd trip. I thought for a year that the trolling motor which was old was dead. Turns out, it had no water in the battery!!! 

If you need water in a battery, use only distilled water. It has the minerals removed that can damage the battery and shorten the life.


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## exide9922 (Aug 9, 2010)

bdawg said:


> First off, don't forget the oars!!! They will always work as long as your arms don't fall off! They've saved me a couple of times.
> 
> Second, check the water level in the battery. I got a new one, used it 2 times before the battery died on me on the 2nd trip. I thought for a year that the trolling motor which was old was dead. Turns out, it had no water in the battery!!!
> 
> If you need water in a battery, use only distilled water. It has the minerals removed that can damage the battery and shorten the life.


Oh yeah I dont go anywhere without oars! i'll have to check the sizes on the batteries, one is an Exide (of course) deep cycle from tractor supply and the other is an Interstate deep cycle from Gander. If I need to charge both batteries should I get 2 chargers if they need recharged that quickly after coming in? I had to wait until the next day to recharge the second one, because the first one took overnight to do


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## KPenny (Jul 31, 2014)

brings up a good point...is it worth getting a battery tender/on board charge to extend battery life?
I have the same issue with my new boat, the gas motor is too large for a 9.9 lake so i run the trolling motor for 3-4 almost constant. I know i'm pushing the battery to it's limit as i've had to break out the oars twice when the battery died. I put the battery on the charger the night before i take the boat out every time. Am i better off to get an on board charger and just keep it plugged in when not on the water?


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## Cajunsaugeye (Apr 9, 2013)

Yes it'd be better but bottom line,you're just using the capacity of the battery.Wont make it last longer on the water.Just will make the battery "live" longer.


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## Cajunsaugeye (Apr 9, 2013)

And put battery on charge after you get back from a trip,not night before you go(except to check and maybe top off).


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## fastwater (Apr 1, 2014)

You say both these batteries are deep cycle batteries. But different brands.

Are they hooked in series? And what else other than the trolling mtr is wired to them?

If they are hooked in series, I can't see them running down in 4-5 hrs if both start out with a full charge and both batteries are good. Even 24 series batteries. Unless you have other things wired to them that are pulling a lot of juice. 

Along with checking the size/series of your batteries, I would check to see how old they are as well. You may have a bad battery(maybe both) not taking a full charge or not holding a charge as they should.

What thrust is your trolling mtr.? What else is wired to the batteries that is pulling juice? How big/heavy is your boat? Do you have a separate reg. battery for your gas mtr.?

In my old glass 18' bass boat with a 150 Merc. on the back, I had two 27series batteries wired in series that would run all day without charging. Would always have the fish finder and usually one of the livewells running that ran off these batteries as well. Now at the end of the day, as soon as I got home, my charger went on these batteries. The third battery was a Reg. battery with nothing wired to it but the eng.

My current boat is a light, 16' aluminum that weighs a lot less than the above mentioned bass boat. Have one 29series battery that operates the trolling mtr. fish/depth finder and livewell. I can run on the 45lb. thrust trolling mtr all day with the depth/fish finder running. The other Reg battery is wired for gas mtr only. 

An on board charger is great to have but you have to make sure you have good batteries to start with. And seeing that you have two deep cycle batteries giving it up after 4-5hrs(especially if they are wired in series) I'm thinkin it's very possible you may be needing some batteries.


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## HamiltonKdog (Oct 15, 2014)

Usually were get 6-7 hours hard use out of our wal mart battery. Last trip battery was really weak after 3-1/2 hours. Well battery is old. A bit of investigation showed a bunch of line wrapped behind the prop. 

Bad or corroded connections or wire can lead to low power to TM as can undersize wire. In our 16ft procraft, changed the original 8 gage wire to 6 gage and the difference was amazing the 1988 45# thrust would run all day whereas before 3 - 4 hours was max.

dont just blame the battery. I have solved a lot of issues just by cleaning all connections and checking resistance of the wire and rewiring when indicated. Helpful chart http://www.westmarine.com/WestAdvisor/Marine-Wire-Size-And-Ampacity


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## richfish (Feb 26, 2012)

i have a 42 lb thrust motor going on my 12ft aluminum semi deep v boat i was planning on buying the 27 series deep cycle marine battery at walmart ,, i want to be able to go out at least 6-8 hours on trips should i get a bigger battery or is 27 ok ? any input would help  thanks


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## laynhardwood (Dec 27, 2009)

Get the 31 series they last a lot longer.


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## derekdiruz (May 27, 2015)

Definitely buy bigger. My 27 series exide blows and I bought it new from Dicks last fall for duck season. I have a 29 everstart that lasts 8 hours with my 55lb trolling motor on 1-2 (of 5) all day trolling. Mind you it's lasted that long without me knowing how much is left on it. It just hasn't died in 8 hours. The 27 has died motoring 500 yards during duck season with a light head wind. We usually have to paddle or walk it back about half way.


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## fastwater (Apr 1, 2014)

richfish said:


> i have a 42 lb thrust motor going on my 12ft aluminum semi deep v boat i was planning on buying the 27 series deep cycle marine battery at walmart ,, i want to be able to go out at least 6-8 hours on trips should i get a bigger battery or is 27 ok ? any input would help  thanks


Like *laynhardwood *and *derekdiruz *stated, with just one battery it would be better to go with a heavier series. Especially if you had anything else (depth finder, livewell etc) drawing power. While the 27 may work, a 29 or 31 series would be better.


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## richfish (Feb 26, 2012)

Great thank you very much for the input guys im going today to get the 31 series i'm glad i did'nt wait my $$ on the lower 
battery


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## Sculpin67 (Dec 11, 2007)

derekdiruz said:


> Definitely buy bigger. My 27 series exide blows and I bought it new from Dicks last fall for duck season. I have a 29 everstart that lasts 8 hours with my 55lb trolling motor on 1-2 (of 5) all day trolling. Mind you it's lasted that long without me knowing how much is left on it. It just hasn't died in 8 hours. The 27 has died motoring 500 yards during duck season with a light head wind. We usually have to paddle or walk it back about half way.


Are you sure that the series 27 exide is good and holding the charge? It seems strange that the 29 is that much better than the 27... I'm assuming that the 27 is motoring less than an hour.

I just bought two WM 27's for a 24v trolling motor.


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## James F (Jul 2, 2005)

You might want to check your charger also.


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