Battery Cell Question

[Plan B]

One of the forward battery cells on my starboard starting battery appears that its water level is dropping much quicker than the other battery cells. The batteries are going in to their 5th year of service. Is this a sign this battery is dying? Does anyone know what would cause this? This is not happening with other house battery.

Thanks,
Plan B

[Peter]

I'm no electrician,but sounds like it's over-charging [will boil thelectrolyte off]

[prowlersfish]

If its just one cell , then you have a bad cell .time for a new battery .

[ready123]

One of the forward battery cells on my starboard starting battery appears that its water level is dropping much quicker than the other battery cells. The batteries are going in to their 5th year of service. Is this a sign this battery is dying? Does anyone know what would cause this? This is not happening with other house battery.

Long answer but am trying to touch many things that may turn on a
Yes sign that it is dying, but how early is it in that cycle... 5 yrs pretty good for a marine use battery if it is used regularly. Is it the cell closest to the +ve terminal?
How much more water does it consume.. small or a lot more?

Some things to check, just guessing here as I don't know how your charging is setup... both via engine and battery charger....
Since it is that engine only I would look at the charging rate of your Alternator... it might suggest that it's too high.
Is the top of the battery ever damp compared to the others?
Some background info reading for those interested in that stuff:
http://www.xs4all.nl/~erkooi/YL/battery.html

To decide on how bad it is you might chart the Voltages of it... say before use on an outing, on arrival at destination, before leaving for return trip.
then compare those numbers with the reference numbers for that manufacturers battery... full charge V, 80% V, 50% V.
If everything tends to be close to the 100% charge number when it should then I wouldn't worry too much just keep an eye on these numbers and keep the water levels up... you do only add water after it is fully charged?
Oh, one other thing... your shore power charger does it charge that battery only or is there another battery combined with it on that charging circuit? If so then we need to consider if they are different sizes and types.
Does the battery have a winter storage non use situation? Is it trickle charged or just stored?
Being just one cell it may not be worth the effort to worry about till it spreads especially if the above checks don't show anything to really worry about.
You do have the Trojan crossover starting system active and working right? If so I would relax for now.

[prowlersfish]

If all the cells were lossing water then you may have a charging issue . But if only one is using water then you have a bad cell (or a leak) Plan and simple. a bad cell can cause the charger to work over time .

[wowzer52]

Get a new battery and you won't have to worry. 5 yrs is a long time for any battery. I've been there. I'm happy to get 3 yrs out of mine.

[gjrylands]

Paul is right. It's time for a new battery.

[ready123]

IMO To really tell if the so called bad cell requires a battery change immediately one needs to check the amount of extra water it consumes (still waiting for you to quantify) and the Volts of that cell compared to the others. Depending on the battery style you may not be able to measure the cells voltage.... you could take it to a battery shop and have load test done on it and that will show if that cell is seriously impacting the battery performance now. It will in time... so you can always just decide to change it now for safety or evaluate by more testing to see how much longer you can use it. Again your setup of batteries should come into these decisions. With my layout I would have low risk to keep it under watch unless water consumption was severe.
My comments are based on how I layout my batteries they are not ganged, if yours are then my suggestions are more risky:
I use a modern 3 stage multi bank charger. I do not use multiple batteries in any circuit, they are always charged one at a time per circuit (by engine or charger). I would only use multiple batteries in a house circuit and then they would be identical make and size to allow for good gang charging.

[prowlersfish]

when a cell goes bad it can use more water due high resistance in that cell . the high resistance causes the cell to get hot and boil the water out .
it will only get worse .

Now a cell with high resistance and no water in it ,is a time bomb .
ever seen a battery blow up ? sometimes its a spark at a cable other times its it a spark inside in a bad cell . when the water boils you get a gas and all it takes is a spark and bang!


Not risky ? a bad battery is risky in more ways then 1 don't try to get more life out of a bad battery its not worth it.

Go a ahead test it to be sure But 35 years of doing this for a living I know what you will find .
.

[TADTOOMUCH]

For the price of a battery and the fact that yours is five years old, I would just buy a new battery, grab a beer and relax. Check the new battery after use for a while to make sure it does not develop the same condition as the old one. You should know after about four trips out on the water.

Also check all your battery and charger connections for corrosion etc. A loose connection will make your alternator and charger work harder and possibly boil a battery.

Most batteries are only warranteed for four years for a reason.