Is my trolling motor battery kaput?

[NakedDog]

I recently purchased a used boat, and therefore never got to put it in the water prior to winterizing the boat.

I pulled the 3 batteries for the boat, including the trolling motor. The trolling battery is a Minn Kota, and the only markings indicate 670 MCA and 125 Amp, and possibly dated March 2000.

The trolling motor is a 24v 70lb Minn Kota.

The issue is charging this trolling motor battery. I'm using an 'intelligent digital charger', and I've charged the battery on 'marine battery mode'. The battery quickly charges to 100% (within 1 hour), and a retest confirms it is at 100%. However, when I check the battery the next day it dips to about 55% charge. Is this battery damaged/ served it's life? Am I doing something wrong?

Any advice or suggestions is greatly appreciated.

 

[trendsetter240]

Re: Is my trolling motor battery not good?

Re: Is my trolling motor battery not good?

It sounds to me like that battery is done. Especially if you got that year right. Most consumer grade batteries do not last 5 years let alone 9 years. A battery with life left in it will not lose half it's charge overnight.

You could bring it into an auto-parts store where they can do a load test for you but likely beating a dead horse. Get yourself a new deep-cycle marine battery, charge it fully and go fishing!

Cheers.

 

[Silvertip]

Re: Is my trolling motor battery kaput?

You don't have "one" trolling motor battery, you have "two" of them if you have a 24 volt motor. Yes -- a battery that won't hold a charge is probably headed for battery heaven. Charge both batteries and take them to any auto store, sears, wally world, etc and have it load tested.

 

[trendsetter240]

Re: Is my trolling motor battery kaput?

One more thing, if you are not going to use the boat until the spring, wait and buy the battery then. No sense buying a battery now only to store it for 6 months. Batteries age and warrenties expire.

 

[NakedDog]

Re: Is my trolling motor battery kaput?

Thanks for the info.

I do realize that I need the 2 batteries wired together for the 24v....and as long as the masking tape I used to mark all the cables don't fall off in the cold winter then I should have everything wired correctly in the spring.

Another related question - do the 2 trolling batteries have to be identical type, power, etc?

 

[trendsetter240]

Re: Is my trolling motor battery kaput?

Thanks for the info.

I do realize that I need the 2 batteries wired together for the 24v....and as long as the masking tape I used to mark all the cables don't fall off in the cold winter then I should have everything wired correctly in the spring.

Another related question - do the 2 trolling batteries have to be identical type, power, etc?

In an ideal situation you should replace both batteries at the same time and the replacements should be identical. In a pinch you could mix "similar" size (read CCA and Reserve capacity) batteries but you may end up with a shorter battery lifespan.

 

[NakedDog]

Re: Is my trolling motor battery kaput?

When I buy a new one, what specifically should I get for a marine battery? i.e.: what is the bare minimum, and what is the cadillac of batteries.

note: as stated, I have a 24v 70lb Minn Kota (probably will not be used often), 17 ft Crestliner with a 115 Johnson.

 

[The Troll]

Re: Is my trolling motor battery kaput?

As far as batteries go ( and I'm going to catch some flack here ) I recommend Wal-Mart's. I run these batteries in my boat which is 36 volt and have had no problems with Wal Mart. When customers ask me which batteries they should buy,I recommend Wal Mart. The group 29 battery is a 205 amp reserve. These are large batteries and may not fit in the battery location in your boat. Remember you are looking for RESERVE capacity not cranking amps. Also if you keep your reciept and your out of town on a fishing trip,and you do have a battery issue,most towns have a "Wally World" your back on the water in no time. I have used them all 'even sold Exide for a while' and you can not beat the price for an 18 month over the counter warranty. Also the $67.00 is not bad. Also batteries have a (born on date) so look at the date and buy the newest as possible. Hope this clears up some battery issues. Your 70# should last you ALL day and then some with these batteries. Good fishin and keep the dry side up.....

 

[Silvertip]

Re: Is my trolling motor battery kaput?

If you happen to live in an area where there are farm stores check the automotive department for Marine Deep Cycle batteries. You need an absolute minimum of two group 24 (the battery case size) but will be far better served by two group 27 size batteries. Check the reserve capacity (minutes) and amp/hr rating on the battery as they are not universally the same in each group size. Higher numbers are better. I buy my batteries at my local farm store and group 27 size deep cycles are about $69 - $79 depending on whether they are on or off sale. The Caddy of batteries would be the AGM or other hi-tech batteries but expect to pay between $350 and $400 for the pair and there is no guarantee they will last longer than the standard lead-acid style. In my view you can buy two and one sets of standard batteries for that price.

 

[Texasmark]

Re: Is my trolling motor battery kaput?

At 70 lbs on your trolling motor, if you do much trolling per outing then the 27's would be a must or the 31 which is a 27 with stud terminals, same otherwise in a marine deep cycle or combo (deep cycle/starting).

I have no problems with WW batteries nor Auto Zone either.

On battery size, my trolling motor has a 12/24v switch. For 12v operation it uses one 12v battery. For 24 volt operation it stacks another 12v on top of the original. Well, the problem with that is that since both batteries are in series, it's like having a flashlight with weak batteries and only replacing one. The light is brighter but not as brite as two new batteries would produce. Same with the trolling motor.

So, if you mix, like get a 24 and a 27 size, make sure that you install the 27 in the slot that is used for both 12 and 24 volt operation. But you may not have the option to select between 24 and 27 in deep cycle batteries. Most stores I frequent have like one rating in each size or may have the combo or in the 24 case size they will have the marine starting only. Course a lot of this is hooey anyway as over time it has been my experience that the two "identical" batteries don't die identically. One usually craps out before the other. Ha!

I agree on waiting to purchase the battery till you actually need it.

I also agree that if you can get 5 years out of a marine battery consider yourself lucky.

Mark