Deep Cycle Battery casing sunked

[BigAl.NZ]

Hello,

I have an issue with my batteries (Endurant 6v 180Ah 8GGC2). I have 4 6v batteries in series-parallel. (So effectively 2 banks of 12v.

Bank 1 started to show 10.2v on the battery monitor, yet if i measure the voltage on the batteries I get 6v and 6.4v (which should = 12.4v).

1. What else could be going on here?

I also noticed on all the batteries, but particularly the 6v one, that the top of the housing is slightly sunken in one or two spots. The rest of the housing, ie the walls of the battery look fine.

2. Is this deformation in the top wall significant?

3. If I take the batteries out for charging on the workbench with a 12v charger, can I charge them as a 12v bank if I my charger doesn't do 6v?

4. If I need to replace one battery in the pair, can I get a similar make/model or do I need to replace the pair? Endurant 8GGC2 6v seems to be a rebadged Deka Dominator 8GGC2.

Al

[Wood]

Have you checked each cell's specific gravity? What are the reading?

[Compass790]

You can only charge your 6v batteries in pairs ( & expect long life) on a 12v charger if their resting voltages are the same otherwise one battery will be getting overcharged & one undercharged.

As wood said you need to check with a hydrometer. I'd suspect one bad cell from your description. If you have no hydrometer take the caps off when bulk charging & look in the cells you might see that one is bubbling way less than the others, that'll be the sick one.
Sunken case is a new one on me, normally they bulge when they are knackered but suspect it's not a good sign.

We have been charging our 6v 225a batteries in pairs on 12v charger for a few years but their resting voltages are the same.

Yr battery thats only showing 6v is likely dragging the healthy one down hence the low voltage on the battery monitor.

those are my guesses.

[Compass790]

Forgot to say wear eye protection when peering in cells to check for bubbling whilst charging & don't make a spark

[Compass790]

Whoops sorry didn't realize they were gel cells.
Have you got a smart regulator setup for gel cells? they need a specific charging regime or you can cook them. Need to be lower voltage charge & float than flooded lead-acid AFAIK.
Same applies to solar controller

[ramblinrod]

Originally Posted by BigAl.NZ

Hello,

I have an issue with my batteries (Endurant 6v 180Ah 8GGC2). I have 4 6v batteries in series-parallel. (So effectively 2 banks of 12v.

Bank 1 started to show 10.2v on the battery monitor, yet if i measure the voltage on the batteries I get 6v and 6.4v (which should = 12.4v).

1. What else could be going on here?

I also noticed on all the batteries, but particularly the 6v one, that the top of the housing is slightly sunken in one or two spots. The rest of the housing, ie the walls of the battery look fine.

2. Is this deformation in the top wall significant?

3. If I take the batteries out for charging on the workbench with a 12v charger, can I charge them as a 12v bank if I my charger doesn't do 6v?

4. If I need to replace one battery in the pair, can I get a similar make/model or do I need to replace the pair? Endurant 8GGC2 6v seems to be a rebadged Deka Dominator 8GGC2.

Al

If the battery monitor is functioning properly, and your DVM is functioning properly, the most likely culprit is a bad connection on the series jumper between the 2 batteries in the pair.

Can’t speak to the deformation without seeing it. Got photos you can post?

[ramblinrod]

Re: Replacing batteries in a pair. First, I’m not sure you need to if you just have a bad connection.

But if you do, . Ideally, all batteries replaced at once get used and recharged equally. If one replaces one battery in a bank, if that battery has significantly lower internal impedance, (ie others are old and SOH is diminished) the new battery will work harder than the others until all batteries are about equal. If the other batteries are near end of life, replace them, if near new, just replace the bad one. In the middle, your call, dispose batteries that still have significant life to get max life from a new bank, or just replace some accepting the new batteries won’t last quite as long as if all were replaced. (It’s a life cycle, peace of mind, and convenience decision).

[ramblinrod]

Re: charge 6 volt batteries as a series pair with 12 Vdc charger. Absolutely. Watch them though. For FLA you need to watch for excess gassing. For sealed batteries, monitor temp with a thermometer. If one gets significantly hotter than the other, could be a bad cell.

[BigAl.NZ]

Thanks for all the replies. A little more information:

I found that one batt dropped a cell and was at 4v (hence the 10.2v reading).

They are sealed Gel, and only 2.6 years old.

In terms of the alternator it is a Balmar with a Max Charge MC614. I will have to check what setting it is set to for charging, but I often see largish (20Amps) current going into the banks.

The Solar controllers are the Gensun GV10's (the older black model). Again will need to see what they are set to.

Hopefully I just can get away with replacing the one bad batt, even if the good ones take a little of the life off it.....

[Compass790]

That's a bummer losing gell cell that quickly.
Could be just a dud but I'd suspect your charging settings. As you will see from the link posted in yr other thread the voltages need to be lower for gels.
Are the batteries in the engine room? As sum1 said cooler the better.
My guess is the sunken top came from that cell getting too hot & softening the top but it's only a guess. Are the sides bulged in the area of that cell too?
Do you motor for long periods? If your bulk charging is set @ 14.8 v that would be pretty bad for gel cells.
Golf cart type FLA's are less fussy if you have to replace bank but can't use just one in a series.

[BigAl.NZ]

Originally Posted by Compass790

That's a bummer losing gell cell that quickly.
Could be just a dud but I'd suspect your charging settings. As you will see from the link posted in yr other thread the voltages need to be lower for gels.
Are the batteries in the engine room? As sum1 said cooler the better.
My guess is the sunken top came from that cell getting too hot & softening the top but it's only a guess. Are the sides bulged in the area of that cell too?
Do you motor for long periods? If your bulk charging is set @ 14.8 v that would be pretty bad for gel cells.
Golf cart type FLA's are less fussy if you have to replace bank but can't use just one in a series.

Hi. Yes the batteries are next to the engine compartment - not ideal.

The Balmar MC614 is programmed to FDc at the moment, which I see is incorrect, it should be gEl for Gel Batteries.

The programs for FDc and gEl differ:


(FDc/gEl)
High Voltage Limit is 15.6 / 15.1
Bulk Voltage 14.6 / 14.1
Absorbtion Voltage 14.4 /13.9
Float Volts 13.4 / 13.7

I will fix that.

We have done a fair bit of motoring, and the boat has crossed the oceans many times with the batteries in the same location - however this was all done by the owner before the previous owner, and it was the previous owner who 2 years ago replaced the batteries with GEL (before that I don't know what they were - but if flooded are flooded more tolerant of heat?)

Cheers.

[Compass790]

I see the genasuns don't have a gel setting but the sealed is close enuff. Don't forget to switch the controller too.
They should have told you when you bought the gel cells about the different charging regime.

[john61ct]

GEL are the fussiest lead chemistry to care for, last longer than AGM if coddled but easy to murder by mistake.

FLA are **much** more robust, long lasting, resisting of abuse than either all 'round, and easiest to replace in remote locations. Just top the water up regularly and keep in the ballpark with mfg specs.

Especially the GC 6V type, Trojan T-105s are very common.

Best is Rolls / Surrette, but priced accordingly.

Maybe only available in NA but if you find Deka/Duracell/East Penn, Superior, Crown, US Battery, all also make excellent FLA for deep cycling.

But any type battery, try to keep them cool as you can.