Reviving sealed gell batteries?

[phil b]

I have about 30 Panasonic LCR12V7.2 ZPI gell cell batteries. I've heard there is a way to add new acid or water to the dried out gell material to revive them. Does anyone have experience doing this? Maybe someone can point me the right direction.

[AbyssUnderground]

Sealed cells have caps on them which you can take off to add water but I've never actually done it, Ive just heard of it.

[Opera House]

I've tried it many times and never had any luck.  Not much you can do for dry and sulfated plates.  Never tried pulsing them to get some life.  I'd say all you have is a toxic waste.

[nothing to lose]

If you can take off the caps and add water, then desulphate them with a pulse charger and that may help allot. Some one will come along that knows more about Gell cells, I only have a couple.

Pulse chargers can be bought or built, most major brands of Smart Chargers have a desulphate mode now, mostly just a pulse charger. Some have an equalize mode also, don't use equalize on gell cells though.

Don't know if you can add water and save them, maybe, and certanly pulse charge for several days to disolve the sulphates that have built up if you can add the water. Also check the tops with a meter from POS to plastic top of case. If you get a voltage reading CAREFULLY wash the top with baking soda and water in a ventilated area, be careful not to get it inside.

 Baking soda neutralizes the acid, good for cleaning tops but bad to do inside the battery to the acid!

I think I just saved a couple of my L16p trojans, they been charging up but going dead fast just sitting, not holding much charge, found the tops were shorted. Washed them and they are doing far better now, time to desulphate again.

[mtbandy]

Hi,

I recently revived a 12v 1.2Ah SLA battery. When I got it, it was registering less than 1 volt between terminals, I guess it had been left for a few years and wouldn't take a charge whatsoever.

I built a sort of 'pulsator' circuit, of my own design. If you're interested, I might be able to draw up the circuit diagram from the lashup in the garage... Basically it was a 60 volt transformer, with a voltage doubler to 120vdc. I then used a 555 and a MOSFET to pulse into the battery at a low duty cycle, at about 1Khz. I series'ed the battery with an inductor for maximum ringing on the 'scope, it's this resonant 'ringing 'that you want to revive the cells. About 36 hours of 'treatment' got this battery to a working level once again and I have it on solar float charge all the time now, and use it to charge my phone. It isn't up to full capacity, but it holds enough to be useful once again.

Basically I think to revive SLAs, the pulser is the way to go. I've tried flushing out wet cells before, without all that much luck.

[Flux]

Probably a waste of time, much depends on what they died of. If they have boiled dry due to a charger fault then you may get some improvement if you can get water into them.

They are normally truly sealed and you will have to drill holes.

If they are old then the plates are likely dead and you have no chance.

If still wet and just sulphated then if they have not been standing long they may respond to pulse charging to get some sort of current flowing then leave on long float charge.

Others claim wonderful results but I have never reclaimed any battery to a really useful state. If you can live with almost useless batteries that will do something then you may achieve your ambition.

Flux

[fungus]

The caps on the sealed cells can be taken off to add water. There is a sort of plastic 'plate' that goes over all of them which has to be pried off and under it there is rubber caps. I tried adding water once to my 17ah sla but it didnt have much affect.. although I did nothing else to it.

[nothing to lose]

Hmm, there is a difference in SLA and Gell Cell, some of the comments are for SLA which is just a sealed battery of normal wet cell type.

As for salvaging batteris I have had good luck on normal Deepcycles. Like those l16p trojans I resqued from a scrap yard. After pulsing for days most of them actually got quite strong and work well for a long period. That was a couple years ago, due to mostly lack of use more recently there are not doing well now. I am trying to bring them back again

Some batteries can be brought back to good heath for a seocnd life, some can't. I geuss pot luck and just try.

It's normally said that a 12V battery at something like 4V sitting would be junk, I have a few working well right now that were at such low volts when I got them, also one in the yard holding about a 13V charge that was 0V in the car I took it out of. It was a good battery untill the car stoped runing about a year ago. Forgotten and left to sit the car drained the battery to nothing. It was about dead when parked from trying to start the car also. I have not put a load on it yet to see if it will do anything, but it charged up and holding volts. Maybe good, maybe not, I did run some little thing off it and it seemed to work, but not really tested it yet.

Always worth a try with the cost of batteries!

[claude]

I recently tried to do the same thing. I have 2 Panasonic 6V/10A SLA's that were used for a few years in a dead UPS. I also have one 6V/4A SLA took from a emergency lamp that stayed on a wall for 7 years and was not operating at all for a long time. This battery is a chinese counterfeit, it's written Pansaonic on it, using the same font, etc. Shameful.

I used a desulphator circuit I made using the schematic I found on the Homebrew site. All the batteries were showing 0.5/1.0/1.2 Volts and 120mA on average each. Pretty much dead. The small one was light as a feather comparing to a new one so I presumed it's dried (7 years on a wall can do that).

I took apart the sealings and the rubber caps underneath and added distilled water to all of them. No change in status. Then I put the two big ones in series along with the desulphator in parallel and left them to charge using a wall adapter (12V/1A). The charging current was at first 20mA. I left the whole thing like that for 5 days and I observed the charging current steadily increasing. After 5 days it got to 1 Amp/h for the two series batteries. Pressure was building inside and I sealed the tops using hot glue.

The small one got the same treatment with another desulphator (I made 2) and a 7.2 wall adapter. The same symptoms, charging current increasing along the 5 days but faster. And this got warm after the 2nd day. The voltage increased to 5V and the amps my meter showed me were about 2-4. I left it there for further treatment.

The two big ones started to charge a lot after 5 days. The voltage was 4.9 and 5.1, the amperage got way up to 8-9 Amps. I had hopes. But after 7 days, to my surprise these two suddenly showed 1.0V each and 10mA (!) They also got warm. I said, well, this is it, it's officially dead. And I was right. Further attempts failed. No change whatsoever. I believe they got shorted.

But the small one, despite its manufacturer is now living a happy life! The amps are all there, the voltage never seems to go lower than 6.1Volts (higher neither) and I consider it a success. Not 100% success, but close. Usable.

My conclusions? I don't know. It takes a lot of patience, a plan, a chart to write down the readings on a daily basis and a bucket full of luck. I guess it's all about luck or how those dead batteries were used before.