Gel battery damage question

[BBC16385]

I have just pulled out two Group 8D batteries that are only four years old. These were bought through West Marine in May of 2007 and are the Deka East Penn Manufacturing batteries. They never performed up to the level of their predecessors, which worked great for eight years and were the same model batteries. From the first year they underperformed and I complained to East Penn but never really pursued it as I should have as a warranty claim. Now they are out and the new batteries are in.

As to one of the two batteries, what does it mean when the top of the battery shows a concave depression at the top of each cell of the battery? In other words, six depressions, three on each side of the top from end to end of the battery. The depressions are about 1/8 to 3/16 an inch deep at the valve.

I think this one battery was defective from the start and it pulled the other down with it. For example, this spring the batteries were showing 11.8 in the morning at anchor, which is completely discharged. The prior batteries never were below 12.3 after eight years.

I would appreciate any advice as to what these depressions on the top mean so that I can avoid the same problems with the new batteries.

Thanks

 

[BBC16385]

No replies. Interesting. I suppose that means no one has seen this or has a theory as to what caused it. I tried sending the question to East Penn on their website email but it doesn't work, of course.

 

[Ed Schenck]

You have cause for concern that there might be a problem with your charging system. I guess if you can check it and be confident then if there is a next time make it a warranty issue.

 

[CarlN]

I'm not sure what the depression means (bulging is a definite sign of a problem) but it seems likely that you had a bad battery. Unfortunately, one bad battery (or even cell) can put a huge strain on any other battery in the set since the charging systems will be confused by the bad one. East Penn has a good reputation. I expect that they would have covered it under warranty.

Having said that, four years isn't terrible. While it's possible to get a lot more batteries seem to average around five years.


Since you got eight years out of your last gels your charging system must be set up well. I'd double check that your charger it is still putting out the right voltage (usually for gels a max of 14.2v temperature compensated). The charger may be failing or someone along the way reset the voltages.

One good practice is to occasionally disconnect each positive cable at your batteries after a charge and measure the voltage of each battery. Connect them up again, draw them down a bit, and repeat the measurement. Any battery that is 2/10s of a volt or more lower than the others should be investigated.

Carl

 

[Dan Johnson]

Those 8D's...

are big mutha's to deal with. You might be better off building your battery banks with pairs of 6 volt deep cycle golfcart batteries. They certainly would be easier to manhandle in and out of the boat, and give you greater flexibility in their lifespans should you be having a charging issue as Ed S. noted.

 

[Ray Bowles]

The depressions on top of the battery could be caused by shrinkage of the materials used to cover and seal the tops of the cells. That was common on older lead/acid auto batteries.
We had that size batteries (5 of them) on our IP 38 and they lasted for 10 years of live aboard use by the PO's and us. We had solar and wind generators of fairly large capacity in addition to the large double belted alternator. Shore power usage is unknown as we don't know what the first owners did.
4 years life on new batteries seems to short. Do you have a good control system that allows you to track amp use and replacement? Do you regulary draw them down or just barely use them before recharge? Are they almost always plugged into shorepower? Are you creating "memory" by slight use and then long times on shorepower? Can you seperate the batteries and test their charges both after use and after sitting. They must be seperatated for the last test. These questions might help others in finding our your problem.
This is a big expense so having an idea of what failed would be good.
Ray

 

[Witzend]

Are you creating "memory" by slight use and then long times on shorepower?
Ray

No memory problem with gel or wet cell acid batteries, only Nicads have that problem.

 

[Steve Dion]

Carl:

4 years on Gel's is bad. One of the major reasons many of us use them is their extended life and the lack of maintenance.

I have 2 Grp 31's on my previous boat and received 10+ years of service.

I would have to agree that you need your shore power charger checked. Proper charging for Gel batteries is mandatory.

I have seen Gel's expand from over-charging but not those indentations, so I am not sure.

 

[CarlN]

"Years" from a battery isn't a very good measure. A boat that is plugged in at the dock most of the time and never discharged more than 20% should get over 10 years. It depends how much you use them. Cumulative amp/hours (or watts) is probably the best measure although that still doesn't get a depth of discharge. As I'm sure you know, a deep discharge takes life out of batteries quicker than a larger number of shallow discharges.

A gel battery that is discharged 80% every day or 50% twice a day is unlikely to last three years. Gels do give more amp/hours than standard lead acid (although not something like a high end Rolls). I once had 2v OPzV type gels on a boat. They have about 3 times the life of a standard gel with a price to match.

If the OP was using his batteries the same way as when he got 8 years on his last set (which he doesn't say), then the four years is short. But maybe he was cruising a lot more.

Much more worrying is his belief that the battery performance wasn't as good from the start but he doesn't explain this comment. It suggests a manufacturing problem but then you would expect a failure in a year (or less). That's why the four years is sort of an odd number.

Still, the best plan would have been to go through the effort of identifying which battery seemed below performance at the start and taking that one back to West. But after horsing those monsters into place I can understand why that didn't seem like a great idea.

Carl

 

[RichH]

Ive had this problem.
In discussions with the East Penn Application Engineers (about 15 years ago), we surmised that overcharging of the gel batts caused the inbuilt pressure relief valve to open (overcharge causes excess heat which causes excess internal battery pressure); when the batts cooled down and with relief valve now full closed a vacuum developed thus allowing the still somewhat hot plastic container to 'creep' and take a permanent deformed shape - additive over many 'pressure release' cycles. Most 'sealed' batteries have a pressure relief system to prevent explosion/rupture when the battery goes 'way above' normal operating temp.
I upgraded my entire charging systems to a precision charging system ('Smart' alternator regulation, 'smart' shore charger, 'smart' wind-gen/solar control, electronic battery 'minder', etc. ... with not a problem since.

BTW ... most such batteries (Gel/mat/acid) will only withstand ~1000 discharge/recharge cycles, then usually need to be replaced. When just 'summer sailing' I could get 8-10 years out of gels, when precisely controlled.

 

[BBC16385]

I want to thank everyone for their helpful replies. The batteries that lasted 8 years were charged by a Freedom 2000. We sail overnight on weekends and anchor out about 3 of 4 weekends a month for six months a season. Leave the dock at full charge, run the generator about 1 to 1 and 1/2 hours that evening, again in the morning and hook up to shore power at the end of the day Sunday for an hour or two. Occasionally, the batteries would get an overnight charge on Friday nights. And we take a three week trip every summer and there is plugging in overnight about half of the trip. The freedom charger was NOT temperature based charging.

The new batteries were charged by the same charger for two years and then by a new Freedom Marine 3000 for the last two years. New batteries were treated no different than the ones that lasted 8 years. When the old 8 year old batteries were removed 4 years ago, they did not have the indentations above the cells as seen most recently: every cell on one battery and one cell on the other battery.

I think the best answer is that the battery with the depressions was bad. I should have pursued a warranty claim with East Penn but did not. I am now wiser! And we are using temperature based charging with the new charger.

I highly recommend Lauderdale Battery & Alternator in Fl for expensive batteries like these. Even with shipping we saved $$$ over West Marine and Defender.