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Sealed Lead-Acid Battery (recovery)

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arhi

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I'm sure I saw gzilion ways on how to (partially) recover the lead-acid battery, but cannot find anything for over 2 hours ?! Either I should go to sleep or something is wrong with the google as I get gzilion of totally useless pages as result...

anyhow a good pointer to article / some explanation will be appreciated ...

I have few (4 to be axact) Panasonic LC-R129CH1 (12V, 9Ah/20HR) batteries.
They are "sealed lead-acid batteries" non-spillable .. blah blah ..

They are from my UPS, and they are dead .. (only cca 5V on the leads) now the questions are:

1. can I try to charge them using slow car battery charger (takes 24H to charge small car battery)?

2. is there a way I can rejuvinate them (pointer to the circuit would be nice, but pointer to the theory would also be appreciated and then I will make/share circuit)

The batt is "sealed" so any "bubbling" has nowhere to go hence booooom if something goes wrong (not big of a problem as I can do it outside but I would like to avoid that if possible)

The rating on the battery sticker:
Cycle use: 14.5-14.9V (25C)
Initial current: less then 3.6A
Standby use: 13.6-13.8 (25C)

Any help on how to rejuvenate/charge is welcome.

p.s. I do not plan to put them back into UPS (I already ordered new ones for that), but I would prefer to use them then to throw them away (Pb is not that "recyclable" in this country)
 
few additional info-s
- the UPS refuse to charge them end reports error "replace batteries"
- The batteries are cca 5-8 years old, working perfectly then left disconnected for 3 years (I turned everything off and left the country for 3 years, when I came back, the UPS worked for few weeks and then shut down with the battery error problem)
 
few additional info-s
- the UPS refuse to charge them end reports error "replace batteries"
- The batteries are cca 5-8 years old, working perfectly then left disconnected for 3 years (I turned everything off and left the country for 3 years, when I came back, the UPS worked for few weeks and then shut down with the battery error problem)
After a careful study of all the info in your posts, I feel that you may better replace the battery.

However, give a try to recover the battery by charging at say 0.5 amp current for a 48 hour period. If it recovers, you may test discharge and try to recharge at 14 hour rate or as prescribed by the battery manufacturer.
As per my experience( from southern part of India - a tropical location), these batteries never took current as perhaps the gel inside got dry.
 
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I already ordered new batteries for UPS, as that is important part of my hw setup and I do not want to mess with what earns me bread&butter... I just want to try to salvage this four cell's to use for something else ...

I was never good with the batteries and the whole "charge theory" .. so I need bit more clarification to understand your hint.

The batteries are lead-acid .. so they should be 13.6V nominal output. When you say charge them with 0.5A for 48H, do you suggest that I build a constant current source and push the 0.5A to them for the 48h, do I need to cap the voltage or should I just ignore it and keep the current to 0.5A? I assume the voltage might get quite high to maintain the current?

Thanks for the help ..
 
I already ordered new batteries for UPS, ...................
The batteries are lead-acid .. so they should be 13.6V nominal output. When you say charge them with 0.5A for 48H, do you suggest that I build a constant current source and push the 0.5A to them for the 48h, do I need to cap the voltage or should I just ignore it and keep the current to 0.5A? I assume the voltage might get quite high to maintain the current?

Thanks for the help ..
Are your batteries Lead Acid or Sealed Lead acid ( so called maintenance free)
By the brand and model you gave last(Panasonic LC-R129CH1 ), they must be SLA type.

The final charge voltage is 13.8V , no doubt,
Mostly battery chargers have some sort of current controll. if you have a charger with current control facility , it helps. please set it to a LOW value of 0.5A

If , in case you don't have, perhaps you have to arrange for one. May be LM317 can be managed in a constant current mode and at 0.5Amps with a suitable heat sink, with input supply at 12+3=15V DC

An initial test is to see whether any 12V battery is taking current thro' it-- would be to check with any 12 V power supply with a 1 Ohm 1 watt resistor in series. The voltage across the resistor would be equal to he current flowing thro it.
 
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it is SLA .. (sealed lead acid)

I do not have charger but I can make one with some googling and poking around for help :) ..

If I understand correctly ... I should provide
13.8V to charge the battery and I should limit the current to 0.5A (I should not "push" to keep the current flowing at 0.5A level, I should just limit the current not to allow more then 0.5A - right? )

that should be fairly simple to make..
 
it is SLA .. (sealed lead acid)

I do not have charger but I can make one with some googling and poking around for help :) ..

If I understand correctly ... I should provide
13.8V to charge the battery and I should limit the current to 0.5A (I should not "push" to keep the current flowing at 0.5A level, I should just limit the current not to allow more then 0.5A - right? )

that should be fairly simple to make..

keep a provision for selecting either 0.25 or 0.5 amps. I moderate the charging as below.

1. charge at 0.25Amps for 24hours. and then
2. next 12 hours at 0.5 Amps.

then try for a discharge for an hour at say 3 amps.(a load like a 12V 25 watt bike headlight bulb )
Perhaps you may go thro' the datasheet of LM317 for constant current source.
 
Try some Inox first... or something similar, I'm not sure of the alternatives.
 
The ones I have have small sealed caps on the top of each cell that are removable.
That said however, I haven't bought one in about 4 years, so they might've changed that...
 
How do you get inox into a sealed lead acid battery?

On some batteries you can see the fill hole in each cell thats been plugged, about 3 to 4mm in dia.
If you dont know already, the electrolyte is a 'gel' not a liquid.
 
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I see the "cap's" on top of the battery but they seam to be "glued" ...

so sealed lead acid is with gel ? not standard acid like car battery ?

hi,
They are not designed to be removable, IF you need to get into the electrolyte, you must carefully drill them out.

No, its not a free running liquid but a semi-viscous gel.

I have had lots of these SLA batteries ruined by customers who have left them discharged for long periods of time, recovery success is less than 5% in my experience...
The technique we used was to leave them on a low charge for about a week.
 
thanks, that is what I did too :( ... I left the UPS (2 of them, 2 batteries in each) for few years switched off. I gather they were fully charged when I turned the UPS off but who knows ... they now have cca 5V each ... I ordered the parts to make charger and will leave them on 0.5A 14V for some time (week or two) and see what will happen. Not that I need them for anything, I already purchased replacement batteries for my UPS's but I cannot recycle them here so the only option (other then use them) is to throw them away in garbage, and I kinda hate doing that.

As for getting into electrolyte, I can drill the holes, but I have no idea what to do with it then, so I will just try to charge them using low current as suggested (I hope .5A is low enough, I will start with .25A for few days and then increase to .5A) so if I get them to charge, great, if not, I'll try to find some eco friendly way of disposing them.
 
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hi,
They are not designed to be removable, IF you need to get into the electrolyte, you must carefully drill them out.

No, its not a free running liquid but a semi-viscous gel.

I have had lots of these SLA batteries ruined by customers who have left them discharged for long periods of time, recovery success is less than 5% in my experience...
The technique we used was to leave them on a low charge for about a week.
Eric,
I used to try this method on SUNCA brand 6V 4.2AH batteries used in the SUNK brand emergency lights sold in India. I can simply use a sharp tool and lever off the rectangular cover plate, get access to the opening of individual cells by again levering off the circular plastic biscuits across the cell opening. One can fine a rubber cap thereafter. remove and we can pour distilled water, if not dilute sulfuric acid.

Finally the battery had to be thrown as it did not pick up charge.
 
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Eric,
I used to try this method on SUNCA brand 6V 4.2AH batteries used in the SUNK brand emergency lights sold in India. I can simply use a sharp tool and lever off the rectangular cover plate, get access to the opening of individual cells by again levering off the circular plastic biscuits across the cell opening. One can fine a rubber cap thereafter. remove and we can pour distilled water, if not dilute sulfuric acid.

Finally the battery had to be thrown as it did not pick up charge.
hi Sarma,
Never tried chopping the top off, just drilling the vents, 'ONCE', its a filthy process and potentially hazardous.

I think the hedge rows of the World are littered with 'dead' SLA's..:eek:

Even when the occasional battery did recover after a long slow charge, they never had the original energy capacity.........its more cost effective to replace the battery.
 
@eric, I replaced batteries already :) ... If I manage to get these ones go back to 12V, I'll put them to some use as "night light" or something "non important". No way I can expect them to reach full capacity as, for one, they are old and for two, they are dead :)

but yes, you are right, there is enormous amount of lead batteries (car batteries, sla batteries) that are littering the world. Some nomad's here put the on fire, and then after they burn out pick up and sell the lead that melts under the fire. Very hazardous process, to the nomad's and to the environment.
 
I thought that most lead acid batteries are recycled in civilised countries.
 
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