Author Topic: Refilling sealed lead-acid battery?  (Read 8168 times)

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Offline mrflux

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Refilling sealed lead-acid battery?
« on: December 28, 2016, 02:21:29 am »
I have seen on YouTube that it is possible to open a sealed lead-acid battery and refill with distilled water.

But I am using the battery in a mobile home, where the liquid is going to splash around inside.
If I open the battery, will it be possible to seal it again?
In the videos, it seems that the caps are held with glue and so forth. And I'm worried that once I remove them, they won't be waterproof anymore, i.e. leaking acid all over the place.

Also, as it happens, I was naive to buy a battery bank that consisted of 3 batteries, one of which is sealed.
I know that they should ideally be identical, but it's a bit too late for that.
When I charge them at 15V to equalize, my carbon monoxide alarm goes off, but only when I am also charging the sealed battery.
The non-sealed batteries can charge even at 15.5V without off-gassing, and even seemingly without loosing any liquid, despite being charged for more than 12 hours at that voltage.

What's going on? Why is the reaction so different?

The unsealed batteries are probably sulphated, because they will only accept charge (3-5A) and reach specific gravity of 1.26 when exposed to high voltage charging (slowly rising until 15.8V). The sealed battery starts off-gassing already at 15.0V and quickly rises to 15.8V, telling me that it is already fully charged.

Nevertheless, I'd like to be able to monitor the water levels of all the batteries.

At least until the battery bank absolutely must be replaced.
 

Offline helius

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Re: Refilling sealed lead-acid battery?
« Reply #1 on: December 28, 2016, 02:45:14 am »
A lead-acid battery only emits hydrogen during equalization, not carbon monoxide. But the sensor in your CO alarm may be sensitive to both, as most are. The alarm threshold for a typical CO detector is 70 ppm, which will also trigger at 700 ppm of H2; an amount that a single SLA can produce easily when equalizing. The reason the other batteries do not produce hydrogen is likely to be that they are sulfated as you already indicated.
 

Offline SeanB

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Re: Refilling sealed lead-acid battery?
« Reply #2 on: December 28, 2016, 05:53:27 am »
Once you pop the top cover off ( some are pretty well glued down though) each individual cell has a rubber vent cap on it, to keep it from losing electrolyte to evaporation. Inside they will have a gel with the acid adsorbed in it, and a separator made from a non woven cloth holding it as well. You only need a very tiny amount of water added to the cell, it will be around 5ml per cell typically taking it from dry to wet, though of course at the time it is dry it will sulphate rapidly and lose capacity.

I have tried this on a lot of them, and most of the time only gotten a little bit of extra life, as they typically are charged continuously, and before you notice the loss in capacity from venting water they have been damaged severely.

If you do refill the cells, the rubber caps just slip back on to seal the cells, and then a little bit of PVC weld will hold the cover back on, just put a small drop where the original joins were, and apply some pressure till the solvent has evaporated out fusing the plastic together. Then it will be sealed like new again, aside from the chew marks on the cover from prying it off.
 
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Offline IanMac

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Re: Refilling sealed lead-acid battery?
« Reply #3 on: January 06, 2017, 09:13:53 am »
It's easy enough done, just don't overdo it or you will have an overflow the next time you charge. I've never known it to extend the life much though. Probably not worth the risk of corroding your UPS or whatever.
 

Offline CatalinaWOW

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Re: Refilling sealed lead-acid battery?
« Reply #4 on: March 30, 2017, 04:17:59 am »
Once you pop the top cover off ( some are pretty well glued down though) each individual cell has a rubber vent cap on it, to keep it from losing electrolyte to evaporation. Inside they will have a gel with the acid adsorbed in it, and a separator made from a non woven cloth holding it as well. You only need a very tiny amount of water added to the cell, it will be around 5ml per cell typically taking it from dry to wet, though of course at the time it is dry it will sulphate rapidly and lose capacity.

I have tried this on a lot of them, and most of the time only gotten a little bit of extra life, as they typically are charged continuously, and before you notice the loss in capacity from venting water they have been damaged severely.

If you do refill the cells, the rubber caps just slip back on to seal the cells, and then a little bit of PVC weld will hold the cover back on, just put a small drop where the original joins were, and apply some pressure till the solvent has evaporated out fusing the plastic together. Then it will be sealed like new again, aside from the chew marks on the cover from prying it off.

As poor as your results have been, they are better than mine.  I have never gotten any extra life from adding water to these batteries.  Anybody is welcome to try, but I suspect you will be disappointed.
 

Online edpalmer42

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Re: Refilling sealed lead-acid battery?
« Reply #5 on: March 30, 2017, 05:37:28 am »
You might have better luck with adding water if the battery is an AGM (Absorbent Glass Mat) type rather than a gel.  I don't see how you could rehydrate a gel.  The amount of water added per cell is difficult to determine.  It will obviously depend on how big the battery is.  If possible, weigh the battery and compare it to the weight shown on the datasheet for that particular battery.  That might give you a clue.  In general, if you can see water in the cell, you added too much.  If you can't see water, it might need more.  Specifics and certainty are highly overrated.   >:D ;)

When you reseal the cell, make sure that you don't completely seal it.  The cell still needs a way to release internal pressure.  If you look carefully at the seal before you open it, you'll see some method of letting gas escape.  As mentioned, there's a rubber cap of some sort under the plastic cover.  Internal pressure will deform the cap, let the gas out, and then reseal.  I've seen some batteries that have a small gap in the edge of the plastic cover to let the gas escape.  Whatever method is used, make sure that you don't block it.

Even after all this, you'll have a battery with plates that have been exposed to the air and perhaps heavily sulphated.  Either can cause such a reduction in battery capacity that you might as well junk the battery.  Together, it's almost a guaranteed death sentence.  Don't expect much, if any, improvement in performance.  I've seen the youtube videos.  I've also experimented with this on multiple occasions.  I haven't had any success.  I also haven't seen a good writeup showing before and after performance.

Ed
 

Offline johansen

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Re: Refilling sealed lead-acid battery?
« Reply #6 on: March 30, 2017, 11:06:28 am »
in the last 10 years i have not found a gel battery. all agm.

agm cells are only filled to about 90% of saturation. you can fill them full, however when they release gas while charging the gas bubbles will expand, are trapped, have no where to go, so if you filled the cell completely full it will push liquid out the caps.

however, you can saturate an agm battery, doing so will reduce the acid concentration by 10%, which will increase the life of the cell and decrease its voltage slightly.

however, you will have to continue to refill the battery because the gas bubbles will float to the top rather than making their way to the other plate where they react with the plate and are re-absorbed.

AGM cells are designed with the PB02 plate larger than it needs to be, so they are only supposed to release excess oxygen, the hydrogen will be absorbed by the pb02, even when fully charged. (unless you over fill it with water and then the bubbles will float to the top rather than reacting with the other plate.)


I have tried this on a lot of them, and most of the time only gotten a little bit of extra life, as they typically are charged continuously, and before you notice the loss in capacity from venting water they have been damaged severely.

i do believe a too high acid concentration due to water loss will increase the internal resistance of the battery, but this is reversible.

its really the too high acid concentration that destroys the positive plate that is what kills the battery quickly. the rate of course is influenced by temperature (every 10C doubles the rate far as i know) so removing the battery from the UPS and locating it in a cool location is a better solution to adding water once a year..
« Last Edit: March 30, 2017, 11:11:58 am by johansen »
 
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Offline CatalinaWOW

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Re: Refilling sealed lead-acid battery?
« Reply #7 on: March 30, 2017, 02:17:48 pm »
I have actually found that the best way to get more life out of these batteries is to re-purpose them as building weights/jigs.  They are heavy and relatively square and can be used to good effect to hold parts in place while the glue dries.  Most glues do not bond well with the surface so not too much care is required in keeping them away from wet joints.  In this application their life is indefinite.  Some I have are going strong after more than a decade at this job.
 
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Offline Vtile

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Re: Refilling sealed lead-acid battery?
« Reply #8 on: April 02, 2017, 02:41:43 am »
Does anyone know if there are any good lead-acid battery "hand-book" that would be worth to get (ideally would have also these Calsium types I see more and more). I have tried to find one, but all I can find is marketing grade "datasheets" or some mystery websites with mystery information.
« Last Edit: April 02, 2017, 02:46:54 am by Vtile »
 

Offline Codebird

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Re: Refilling sealed lead-acid battery?
« Reply #9 on: April 02, 2017, 11:41:45 am »
Quote
Does anyone know if there are any good lead-acid battery "hand-book" that would be worth to get

Something like this?
http://www.exide.com/Media/files/Downloads/IndustEuro/Operating%20Instructions/Handbook,%20part%201,%20edition%206,%20Feb_%202012.pdf


 

Offline Vtile

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Re: Refilling sealed lead-acid battery?
« Reply #10 on: April 04, 2017, 08:08:51 pm »
Quote
Does anyone know if there are any good lead-acid battery "hand-book" that would be worth to get

Something like this?
http://www.exide.com/Media/files/Downloads/IndustEuro/Operating%20Instructions/Handbook,%20part%201,%20edition%206,%20Feb_%202012.pdf
Yep, that is the style of book I were looking at. Thank you.
 

Offline sibeen

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Re: Refilling sealed lead-acid battery?
« Reply #11 on: April 04, 2017, 08:57:56 pm »
I've seen it tried once in a professional setting on some quite large UPS systems. The batteries were very expensive 15 year design life and the attempt was made at about the 8 year mark to extend their life. It did not go well. It was very fortunate that no-body was in the battery room a few days later, as serious injury was certainly possible. I do know that this major player in the large UPS industry never attempted this again.

I would advice against it.
 

Offline tantragna

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Re: Refilling sealed lead-acid battery?
« Reply #12 on: July 11, 2017, 02:37:30 am »
I have done this with my micro-CV's battery and quite successful. However the max.voltage never rose beyond 12.8V after adding sufficient distilled water until I could see it via the rubber capped vents. Initially they were less than a couple of volts, and the local battery shop refused to revive it saying it as a dead battery. Go ahead and give it a try, if they are of that risk of loosing it out for nothing. Good luck!
 

Offline Mosaic

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Re: Refilling sealed lead-acid battery?
« Reply #13 on: May 13, 2018, 07:15:12 am »
I have started deploying professional/portable battery regenerators of my design/build.
In Africa where ambient temperatures hit 45 C, it IS necessary to decap sealed cells, add water and recap with hot glue in order to regenerate the batteries.

Africa Heat = water lost= battery loses capacity = battery being overcharged = more battery heat = more lost water = plate exposure & high acid conc. & sulfation, battery loses more capacity and dies.

Only by adding distilled water do these batteries have a chance of some capacity restoration. A 20 to 25% OEM capacity seems to be average upon regeneration. This is perfectly viable for deep cycle as they can be paralleled into the storage array.
 

Offline jh15

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Re: Refilling sealed lead-acid battery?
« Reply #14 on: May 24, 2018, 02:01:39 pm »
I have actually found that the best way to get more life out of these batteries is to re-purpose them as building weights/jigs.  They are heavy and relatively square and can be used to good effect to hold parts in place while the glue dries.  Most glues do not bond well with the surface so not too much care is required in keeping them away from wet joints.  In this application their life is indefinite.  Some I have are going strong after more than a decade at this job.
Yes! I use them on my chipmunk "restaurants" An Amazon A3 box with flaps glued over for strength. a 1.25" (use my pinkie finger bone). Inside a Victor RAT trap, never had good results with the blackcat brand. Plastic baggie spray glued on the roof. Cardboard lasts all season.
Then, a repurposed 12AH lead battery from my electric bike or UPSs.
     Beginning of season I have over 25 a week "served". 2 restaurants. 
     Best rated menu is Skippy peanut butter, chunkey or not chunky, infused with the bird feeder food they raid.

A couple nights, when left out, box overturned, trap gone! So I set out a camera, saw Coons! all around it but they preferred eating elsewhere that night.

For fun I put Italian restaurant (not at the end of the galaxy) motif, menus, or maybe all you can eat, etc, in case neighbours or yard workers see it.

To leave out at night maybe I'll have to go to depleted uranium for more mass.
tek 575 curve tracer top shape, 535 top shape, 465. 545 hickok clone, Telsa Model S,  Ohio Scientific c24P single board computer, many c-64 from my club days, Giant electric bicycle, Rigol stuff, Heathkit AR-15 receivers 2, Heathkit et 3400a trainer and interface,
 

Offline ElektroQuark

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Re: Refilling sealed lead-acid battery?
« Reply #15 on: May 24, 2018, 03:15:37 pm »
Quote
Does anyone know if there are any good lead-acid battery "hand-book" that would be worth to get

Something like this?
http://www.exide.com/Media/files/Downloads/IndustEuro/Operating%20Instructions/Handbook,%20part%201,%20edition%206,%20Feb_%202012.pdf

A year later it's not available. Any other link?

Offline jh15

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Re: Refilling sealed lead-acid battery?
« Reply #16 on: May 24, 2018, 03:34:49 pm »
Not for your problem, but related, may inspire others:
Living on 12 volts. from my local town library. Had to keep renewing it.

cool stuff, mostly yachting, tossing out a generator on a line, metal plate to keep cold in refrigerator,  and cool for anyone: Fill the empty space in your fridge with balloons. Otherwise, all the cold air falls out.
« Last Edit: May 24, 2018, 03:37:42 pm by jh15 »
tek 575 curve tracer top shape, 535 top shape, 465. 545 hickok clone, Telsa Model S,  Ohio Scientific c24P single board computer, many c-64 from my club days, Giant electric bicycle, Rigol stuff, Heathkit AR-15 receivers 2, Heathkit et 3400a trainer and interface,
 

Offline JohnnyMalaria

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Re: Refilling sealed lead-acid battery?
« Reply #17 on: May 28, 2018, 11:28:29 am »
Please, be very careful. If you should spill any of the liquid (assuming not the gel type) then you could be in a lot of trouble.

1. Wear heavy clothing - absolutely no shorts
2. Rubber gloves
2. Have baking soda or ammonia nearby in case you spill any
3. Protect your eyes

Just precautionary but wise. You simply never know. (I've been handling concentrated acids for years and have seen some unfortunate things.)
Tell me it can't be done and I'll do it. Or die trying.
 

Offline TerraHertz

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Re: Refilling sealed lead-acid battery?
« Reply #18 on: June 03, 2018, 06:01:14 am »
Collecting old scopes, logic analyzers, and unfinished projects. http://everist.org
 


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