# 6 Volt Trojan T125 With A Dead Cell.



## Herbicidal (Aug 29, 2003)

I don't have an actual date but I think our dual 6volt Trojan T125's are about 3 1/2 years old. First, I have a confession to make, I had posted a question about whether to get two 6 volt chargers or stay with my older, very basic 12 volt charger and charge the batteries in series. The recommendation was to save my money and use the 12 volt charger. Well, a couple of weeks later I ended up buying two 6 volt chargers (Battery Tender Plus) and hooked them up to the Trojans that are sitting in my garage. After about 4 days, the green light came on the first one indicating a full charge. Two more days go by and the 2nd battery still shows charging. What the heck? I unplug the chargers and switch them to the opposite battery and plug them back in. Within an hour, battery number one on charger number two says charged. Battery number two still says charging. I leave it like this for two more days and it's still charging. I decided to buy a hydrometer. I check all 3 cells of the "good" battery and they are fully charged, almost off the scale. I check battery number two and the first two cells are fully charged, the third and final cell...dead. Explains why the charger never indicated fully charged! I've never let the water get low enough to ever expose the top of the plates and I always use distilled water to top them off. I have no idea how long there has been a dead cell either.







If I had continued to use the 12 volt charger, who knows how long I would have gone without any clue there was a dead cell. Oh well.

So, I now have one good battery and one battery that has a dead cell. I understand the general rule of thumb is to replace batteries in pairs (these suckers are getting expensive!). We don't have any trips planned right now and I'm wondering how long I can use the batteries like this? Continuing to maintain them, of course. Unless it's a full hookup campground, we always bring our generator as a back up to recharge them when they get low. So even if the battery life is less than two fully functional batteries, am I hurting anything by running them like this? Or is it just that I don't have the capacity of two fully functional batteries? How long are well maintained 6 volt batteries supposed to last anyway?

Sorry the post became rather long. Thanks for your input!


----------



## sunnybrook29 (Oct 7, 2009)

Three and a half years is long enough. Here at Sams Wholesale those batts where about $80 each. I do not believe that you will damage any thing running with a bad cell, we all do it , we just do not realize it until they let us down!
What kills most batteries in TTs is constantly charging and boiling the water out! Does your tt not have a converter charger? If so , why do you need extra chargers?
Remember that when you wire two sixs in series they become "one " 12volt battery and can be treated and charged as one 12 volt battery! A " battery " is a group of "cells" stacked in any kind of package.


----------



## CamperAndy (Aug 26, 2004)

You may take it to a battery store to see if it can be helped with a desulfator. The mostly issue is the plates are shorted and a desulfator causes the charge to modulate in such a way that it knock the sulfide (shorting debris) off the plates. The biggest problem is this only extends the life but does not fix the issue. The batteries you have are very good and should last 5 to 7 years with good care. You can also rejuvenate the batteries by draining the electrolyte, then rinsing the cells out with distilled water to remove the sediment from the bottom. Then refill with fresh electrolyte.


----------



## Herbicidal (Aug 29, 2003)

sunnybrook29 said:


> You may take it to a battery store to see if it can be helped with a desulfator. The mostly issue is the plates are shorted and a desulfator causes the charge to modulate in such a way that it knock the sulfide (shorting debris) off the plates. The biggest problem is this only extends the life but does not fix the issue. The batteries you have are very good and should last 5 to 7 years with good care. You can also rejuvenate the batteries by draining the electrolyte, then rinsing the cells out with distilled water to remove the sediment from the bottom. Then refill with fresh electrolyte.


Thanks CamperAndy, I'll give the battery store that I bought them from a call and see if they can do the desulfator and/or drain/rinse and re-fill. In the meantime, it seems like they're OK to use, just with reduced capacity and since we use a generator as well, I guess we're OK until they flat out die. Oh, I still had the sticker with the price on it stuck to one of the batteries: $109.99. From the same store today, he quoted me $169.99. I had to ask him twice about the price!


----------



## Carey (Mar 6, 2012)

I had a battery with a broken connection from the plates to the post explode in my face once.

I had stopped of at a store in my 71 Blazer. I came out and it wouldnt start. I popped the hood and when I wiggled the ground post it exploded in my face. The top of the battery blew in severl pieces and got me. My cheek got badly bruised and I had to get a few stitches.

The worst part was I wear hard contacts. I took them out on the way back into the store and let em fly. I went to the bathroom and doused my hurting head and eyes with water. I had a chemical burn in my eyes. That was rather painful.

All of my clothes were ruined as was the entire front end of my show piece Blazer. I had just won the super chevy show for best paint. I was more mad about that then my face, lol

I had to tear it all back down and repaint it.

I learned when a battery starts acting wierd that its best to be very careful around them.

Im sure yours will be fine. Just be careful Herb.

Carey


----------



## Herbicidal (Aug 29, 2003)

Thanks Carey and I will.

I looked up Trojan's web site (http://www.trojanbattery.com - couldn't get the link function to work with IE6 here at work







) and found a way to e-mail tech support. I've asked them some questions about the bad cell, replacing them in pairs and so forth, we'll see what they come back with.

They do have some good info on the site and I think it's worth a few minutes looking through the battery maintenance section under the Tech Support heading.


----------



## ELSEWHERE (Sep 16, 2007)

It might not apply to two batteries used in series but with two batteries operating in parallel one bad one will draw the other down faster. It's usually recommended to replace them at the same time. Hopefully they'll tell you it's O.K. to replace just the bad one when being used in series.


----------



## Herbicidal (Aug 29, 2003)

I e-mailed Trojan and received a reply today.

*Here's my e-mail to them:*
"Hello, I have two T-125 6v batteries that I run in series for our travel trailer that are about 3.5 years old. Currently the batteries are in the garage on individual 6v chargers (Battery Tender Plus). I noticed one charger was not indicating that the battery was fully charged. So I bought a hydrometer and discovered one cell is "bad". I've never let the cells expose the lead (go dry)and always fill them (when needed) with distilled water. My dealer said that batteries should be replaced in pairs, but I would prefer not to do that at this time, especially since one of them is in perfect condition. I have no idea how long I've had a bad cell. Is there a possibility of correcting it? Is the battery safe to operate with the bad cell while in series with the other? Do I really need to replace them in pairs? Thank you for your time."

*Trojan:*
_"Ideally, the entire set of batteries should be replaced. The behavior of batteries during discharging and charging varies throughout their lifespan and if all the batteries are the same age, than they all will have similar responses. You can, however, replace just the one bad battery with a new battery, but you will have to keep a close eye on the new battery as it will consume more water than the older batteries. The danger with replacing only one battery is that the older batteries tend to require more charge than newer batteries, and since the new batteries are in the same circuit, they too will be overcharged. There is also the chance that the older batteries will be undercharged since the overall voltage response of all the batteries (old and new) will not be a good representation of either group. The charging system might erroneously think that ALL the batteries have reached the desired voltage and it may stop the charging of the batteries prematurely. Simply make sure that you keep a close eye on your batteries and you should be okay."_

*My follow up question:*
"Thank you for your response. Regarding the one bad cell, is there a chance of reversing it's condition? Such as removing some of the water from it and replacing it with some from each of the remaining good cells from both batteries? Is there anything an authorized Trojan dealer can do for the bad cell? Lastly, any safety issue with one bad cell that I need to be concerned about?

*Trojan:*
_"No there is really nothing that can be done to bring back a dead cell. The only safety concern would be if the charger does not stop the charge because of the dead cell."_

So for now, I'm not going to replace the 'bad' battery. I'll monitor the water more closely and see how it goes over time. Thanks everyone for your feedback.


----------

