36 Volt series Trolling Batteries (1 needs replaced) Question

[BassCatKev]

There has been a sewer smell in my garage. I figured it was some marina water that remained in the bilge and hoses that caused it. Now I realize it's from having a bad battery. My 4 bank charger has been showing that 1 of my 3 trolling batteries is never reaching full charge (3 orange lights but never making green). The smell eventually goes away when charger is unplugged.
I need to disconnect and remove this battery from the bilge cage. I know which one it is thanks to the labeling on the Minn-Kota charger.

What are thoughts on how to replace?

I've read a lot of threads discussing what best batteries are and not trying to start another one. I'm leaning toward going to Sam's and getting their Duracell 31 lead/acid that so many on here praise. I really don't want to replace all 3. So is the goal to make sure the new one is of similar amps?

Thanks for your help as always

I have a cheap tester but assume this battery is toast?

[twitch]

depending on how old the others are it is not a good idea to replace just one out of the 3 batteries. I know 3 is a greater cost but if the others are older it would be a better choice to replace all at once

[John Jackson]

I've replaced only the bad ones all my life with no ill effect. Even 3 identical new batteries will have differences, sometimes significant differences.
Before you replace the "known" bad one, swap leads just to make sure that charger bank isn't bad and trying to overcharge. I've had that happen and ruin good batteries.

[RANGER487]

I don't have an even rotation of batteries by years and have replaced 1 or only 2 before with no issues they maybe a year a part or so.

[BassCatKev]

The others are January 2017. They came with the boat. They show no sign of weakness. The other two would have been discharged and recharged all at the same times under the same conditions. I guess they aren't all made equally.
This issue caused me to have to take the top off the battery cage (that's what I call it) to be able to remove the bad one. I know it's for a good reason, but taking the 6 screws that hold down the top of the cage holding the 2 batteries on the port side was not easy for me. I guess that's a reason to replace the others while I'm at it. But who knows they could have years left.
All 3 of my trolling batteries are Masons 31 size. I assume they're lead/acid since I don't see AGM anywhere on them.

Sam's is running a sale on Duracell starting tomorrow.

[mactlman]

i would try one and if it seems to be an issue, replace other two next spring? never heard of a brand named "mason"?

[Skeeterbait]

Here is the risk. It is not great but it does exist. If batteries are wired in series and if one battery were to be lower capacity, due to battery size, age, internal resistance, or other internal fault, and if you were to run your set of batteries down long enough that that specific battery were to completely exhaust its reserve capacity, then that specific battery will receive reverse polarity charging from the other battery in the set. Now this will definitely ruin the battery. If this occured because it was just simply smaller, then you have ruined a good battery. But it can also cause heat and pressure to build causing a spill or rupture. So it takes a worse case situation and specific situation, but the risk is there. To be as safe as you can with batteries wired in series, it is best that the batteries are matched in size, capacity, age and known good without internal fault.

[jimsch]

I would switch leads to verify it is the battery. My 440PC did that. Switched leads to check and it showed the other battery was now bad. New charger, no more problem.

[BassCatKev]

I've replaced only the bad ones all my life with no ill effect. Even 3 identical new batteries will have differences, sometimes significant differences.
Before you replace the "known" bad one, swap leads just to make sure that charger bank isn't bad and trying to overcharge. I've had that happen and ruin good batteries.

I put a tester on the battery and only red LED came on indicated it's bad. I put it on the other 2 and they went all the way to green. So I assume I for real have a bad battery. But maybe I still need to check the leads on that bank as you suggest.

[BassCatKev]

i would try one and if it seems to be an issue, replace other two next spring? never heard of a brand named "mason"?

All three say Mason. They're size 31 batteries. They were either installed by BassCat or the previous owner used them. He was from Michigan so maybe it's a brand common in that area. Previous owner said he used them the entire year he had the boat.

[BILL LO]

I have replaced only 1 battery before , no issues

[John Jackson]

I put a tester on the battery and only red LED came on indicated it's bad. I put it on the other 2 and they went all the way to green. So I assume I for real have a bad battery. But maybe I still need to check the leads on that bank as you suggest.

A bad charger can make a battery bad. If it is a charger a tester would still chow a burned up battery as bad. By swapping your leads temporarily, you are checking the charger to make sure it is OK. Either way you still have a bad battery. You just want to make sure your charging bank isn't burning up the batteries.

[BassCatKev]

I've been reading a different thread and apparently I've been in the dark all these years regarding adding water to batteries. I've read and heard about doing this forever but always thought since I owned "maintenance free" batteries that it was never required. Is it possible that I could add water to my battery (I'm going to look for an access on the top of it when I get home) and it will be good again?

[DQM]

There is a chance, if it is low, that the low water is the only issue causing it not to charge.

Most likely, however, it is toast probably as a result of of low water for long period of time. But doesn't cost anything but time to fill it and try it.

If you cannot easily, or just plain do not want to, check the water levels periodically then I would switch to AGM batteries and not worry about having to do it ever again.

[billnorman1]

If the battery is sealed (called maintenance free) or an AGM you cannot add water by ordinary means. A battery low on electrolyte (water) will stink if charged, because the remaining water is boiling as it is small compared to the amount necessary to conduct current. It might indeed be a bad charger. A shorted cell battery can also stink.
Buy a lottery ticket. Win. Then go to Sam's club and buy 3 batteries if you have a 36 volt troller. You don't need the size 31 AGM's there are cheaper Duracells BUT you will probably have a killer system if you do.

[BassCatKev]

I popped the two top seals off. There were 3 cavities under each cap. I didn't shine a flashlight down in there to see the very bottom, but saw no evidence of water in any of the 6 holes. I'm going to buy some distilled water this afternoon just to have.

As DQM stated, it wouldn't hurt to fill them up and try.
I don't see any directions on the battery. But I assume you just fill the cavities to the tip top and snap the caps back on?

I know this isn't a good thing, but I've charged this battery multiple times while it was apparently out or low of water. That rotten eggs smell occurred multiple times. I didn't realize that was being caused by charging for several charging cycles until I figured it out.

What is the chance that just adding water will fix this battery and I can resume using it? Would you all try it at this point?

[Dan21XRS]

Fill so it covers the lead plates... Not too much... Check the others also... Dan

[DrewFlu33]

Fill so it covers the lead plates... Not too much... Check the others also... Dan

Yep, this. If you fill it so that it touches the plastic it will boil over when charging which creates a different kind of mess.

[BassCatKev]

Thanks everyone. I'll give it a try. It'll be intetesting to see if this battery can be revived. If it can, I'll keep using it and consider new on the spring if necessary.

[BassCatKev]

Battery was WAY low on water. I just filled it above the plates and snapped top back on. I just put my cheap battery tester back on it and it shows red (low). Is water required to be over the plates in order for it to properly charge? It was getting charging current a plenty while it was hooked to in board charger. But maybe that was useless since low on water?

I'm going to borrow a manual charger and try it but just curious if wasting my time. I'm learning either way.