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Topic: Reviving Gel Batteries? (Read 870 times) previous topic - next topic

Reviving Gel Batteries?

I have two 4D gel batteries for my coach. They are not holding a charge even after hooking them up to my battery charger (in gel battery mode). These gel batteries are $500 each to replace. Is there anything I can do to prolong their life?

Even though the caps say "DO NOT REMOVE", they do come off (intentional and accidentally). It looks dry and all crystallized at the top from what little I could see. I think the previous owner had a bottle of distilled water in the battery compartment.  Clue? 

I am not sure of their age. I bought the coach 1-1/2 years ago and I have not replaced or serviced them. I just know they are not holding a charge.
Fred H.
1996 Foretravel U320 4000 Build #4993 (Previous motorhomes 1985 Airstream 345, 1977 Argosy 20)
Sevierville, TN
ViewRVs.com

Re: Reviving Gel Batteries?

Reply #1 –
Those caps are pressure relief valves.  There should never be a reason to take them off.  You would never add water to a GEL battery because they use a gel that does not evaporate under normal circumstances and is not replaceable.  If they aren't already ruined, adding water would probably finish them off and could be dangerous.

If they are drained too low, it's possible that your charger isn't seeing them as a battery and therefore not charging them.  If you are seeing your charger putting amps into the battery and you're reading voltage while it's running, and they don't hold the charge after disconnecting, they're probably shot.  If the charger isn't trying to charge them, you can trick it into starting by temporarily attaching a working battery in parallel.  Remove it after charging starts.  If you have to do that, the batteries are probably still bad but worth trying.

Re: Reviving Gel Batteries?

Reply #2 –
The charger does indicate that it is charging. I got them up to 6.4 volts and they both dropped to below 3 by morning (with nothing connected to them).

I was at a campsite for the whole month of July connected to 50 amp service. When I disconnected from shore power, the batteries barely had enough juice to start the generator. 
Fred H.
1996 Foretravel U320 4000 Build #4993 (Previous motorhomes 1985 Airstream 345, 1977 Argosy 20)
Sevierville, TN
ViewRVs.com

Re: Reviving Gel Batteries?

Reply #3 –
Quote from: ViewRVs –
The charger does indicate that it is charging. I got them up to 6.4 volts and they both dropped to below 3 by morning (with nothing connected to them).

I was at a campsite for the whole month of July connected to 50 amp service. When I disconnected from shore power, the batteries barely had enough juice to start the generator. 
Pretty sure those are 12 volt batteries, 6.4 indicates a shot battery.
Jim C.
coachfree, previous 1997, 1999, 2000, and 2003 Foretravels.

Re: Reviving Gel Batteries?

Reply #4 –
There should be some markings on the batteries to indicate their age.  If you can't decipher it then Deka probably can.

Maybe your inverter/charger isn't charging.............something to check.

Re: Reviving Gel Batteries?

Reply #5 –
"All lead-acid batteries release hydrogen from the negative

plate and oxygen from the positive plate during charging.

VRLA batteries have one-way, pressure-relief valves.

Without the ability to retain pressure within the cells, hydrogen

and oxygen would be lost to the atmosphere, eventually

drying out the electrolyte and separators."

Gel batteries are VRLA...

No choice buy batteries.  If you never dry camp, you my get along with just one 8D Gel. You can also buy wet cell 8D's if you want to deal with refilling and battery acid in the bay.

Re: Reviving Gel Batteries?

Reply #6 –
You could try putting them on a pulse desulphator for a few weeks. It may be able to dissolve the crust on the plates. Buy a high-quality, high-capacity desulphator. It will cost you big dollars.

Since the above only has a 15% chance of working, it may be better to just replace the batteries.
1997 U270 34FT Build 5140 Cummins 8.3 Allison 3060R
Solar 1920Watts, 14KWH lithium. Orion BMS.

Re: Reviving Gel Batteries?

Reply #7 –
Quote from: Tim –
Since the above only has a 15% chance of working, it may be better to just replace the batteries.
x 2.
1993 U225 Build #: 4285
500 Watts Solar
Honda CRV AWD
Former 1981 Foretravel Travco
Retired, Full Time Off Grid Snowbird

Re: Reviving Gel Batteries?

Reply #8 –
To me the big question is what caused the problem.  If the batteries are simply over age, then replacing them solves the problem, but if they aren't over age what is the problem?  Something has to have killed them.  Putting in new batteries without know what killed the old ones is a good way to ruin the new ones.  The most common methods of killing a battery are overcharging, or over discharging.  On both my old RV and my U280 the previous owners had used the original power converters and left the coach plugged in all the time.  Those old power converters are not really battery chargers.  The peak voltage goes too high, and it it easy for the batteries to go into thermal runaway.  As they are overcharged the batteries heat up which drops the internal resistance causing them to draw more current which makes them hotter, dropping the resistance even more and so on.  Eventually the charger/converter is pushing full output and the batteries are starting to stink.  The batteries slowly cook to death.  Eventually they vent, loosing moisture and capacity and sometimes even warping the plates.

What kind of charger/power converter do you have installed in the coach?  If it isn't a multi-stage unit, it may be the real problem.
Mike & Lilli
1991 GV U280 36' SBI, 3208 Cat, Build #3825
4320 Watts Solar
Kansas City, MO

Re: Reviving Gel Batteries?

Reply #9 –
Any high tech battery that can't be revived from an accidental over discharge is engineering and environmental stupidity, stuff happens. Solid plate 6v golf cart batteries are ocean sailors friend. Lithium ion have a realtively narrow temperature range. Fine for some locations. One size/technology fits all is just a failure looking for a place to happen. Just my 2 cents.
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake
 

Re: Reviving Gel Batteries?

Reply #10 –
The available batteries are damaged if run flat.  Just reality
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4