Refilling sealed lead-acid battery? - Page 1
Forum section: electronics / general

author: mrflux
author_rank: Contributor
timestamp: December 27, 2016, 03:21:29 pm
content: 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.

author: helius
author_rank: Super Contributor
timestamp: December 27, 2016, 03:45:14 pm
content: 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.

author: SeanB
author_rank: Super Contributor
timestamp: December 27, 2016, 06:53:27 pm
content: 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.

author: IanMac
author_rank: Newbie
timestamp: January 05, 2017, 10:13:53 pm
content: 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.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: March 29, 2017, 05:17:59 pm
content: Quote from: SeanB on December 27, 2016, 06:53:27 pmAs 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.

author: edpalmer42
author_rank: Super Contributor
timestamp: March 29, 2017, 06:37:28 pm
content: 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.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

author: johansen
author_rank: Super Contributor
timestamp: March 30, 2017, 12:06:28 am
content: 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.)Quote from: SeanB on December 27, 2016, 06:53:27 pmi 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..

author: CatalinaWOW
author_rank: Super Contributor
timestamp: March 30, 2017, 03:17:48 am
content: 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.

author: Vtile
author_rank: Super Contributor
timestamp: April 01, 2017, 04:41:43 pm
content: 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.

author: Codebird
author_rank: Regular Contributor
timestamp: April 02, 2017, 01:41:45 am
content: QuoteSomething like this?http://www.exide.com/Media/files/Downloads/IndustEuro/Operating%20Instructions/Handbook,%20part%201,%20edition%206,%20Feb_%202012.pdf

author: Vtile
author_rank: Super Contributor
timestamp: April 04, 2017, 10:08:51 am
content: Quote from: Codebird on April 02, 2017, 01:41:45 amYep, that is the style of book I were looking at. Thank you.

author: sibeen
author_rank: Frequent Contributor
timestamp: April 04, 2017, 10:57:56 am
content: 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.

author: tantragna
author_rank: Newbie
timestamp: July 10, 2017, 04:37:30 pm
content: 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!

author: Mosaic
author_rank: Regular Contributor
timestamp: May 12, 2018, 09:15:12 pm
content: 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.

author: jh15
author_rank: Frequent Contributor
timestamp: May 24, 2018, 04:01:39 am
content: Quote from: CatalinaWOW on March 30, 2017, 03:17:48 amYes! 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.

author: ElektroQuark
author_rank: Unknown
timestamp: May 24, 2018, 05:15:37 am
content: Quote from: Codebird on April 02, 2017, 01:41:45 amA year later it's not available. Any other link?

author: jh15
author_rank: Frequent Contributor
timestamp: May 24, 2018, 05:34:49 am
content: 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.

author: JohnnyMalaria
author_rank: Super Contributor
timestamp: May 28, 2018, 01:28:29 am
content: 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 shorts2. Rubber gloves2. Have baking soda or ammonia nearby in case you spill any3. Protect your eyesJust precautionary but wise. You simply never know. (I've been handling concentrated acids for years and have seen some unfortunate things.)

author: TerraHertz
author_rank: Super Contributor
timestamp: June 02, 2018, 08:01:14 pm
content: Quote from: ElektroQuark on May 24, 2018, 05:15:37 amGoogle for 'Exide Handbook part 1 2012' finds it:http://www2.exide.com/Media/files/Downloads/IndustEuro/Operating%20Instructions/Handbook%2C%20part%201%2C%20edition%206%2C%20Feb_%202012.pdfBtw:http://everist.org/NobLog/20180430_lead_acid_ruin.htmTeardown of a ruined lead-acid battery

author: benryanau
author_rank: Contributor
timestamp: January 05, 2020, 02:46:25 am
content: WEIGH and RECORD results for each battery.. cradle to grave will help get eyes into an SLA.Use accurate and hi-res scales.

author: bob91343
author_rank: Super Contributor
timestamp: January 05, 2020, 06:15:12 am
content: I have an old HP voltmeter that came with a rechargeable battery. Of course the battery is old and toast. It's made by Gates and has three lead-acid cells.I wonder if I could break into them and add water to make them useful again.

author: james_s
author_rank: Super Contributor
timestamp: January 05, 2020, 06:24:59 am
content: I seriously doubt it.Are they like these?https://www.osibatteries.com/p-849-hawker-gates-enersys-cyclon-0810-0004-pure-lead-battery-2v-d-cell.aspx

author: tautech
author_rank: Super Contributor
timestamp: January 05, 2020, 07:11:42 am
content: Quote from: bob91343 on January 05, 2020, 06:15:12 amNope, waste of time and effort as the lead plates will be too badly sulphated.As they say; it's dead Jim !

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 05, 2020, 03:53:36 pm
content: Quote from: bob91343 on January 05, 2020, 06:15:12 amA 2S LiFePO4 pack would be a nice drop in replacement for 6V lead acid.

author: james_s
author_rank: Super Contributor
timestamp: January 05, 2020, 05:12:04 pm
content: Quote from: NiHaoMike on January 05, 2020, 03:53:36 pmI don't think I'd want to charge it with the original charger and that would be a hassle since typically batteries like this are charged by the equipment while it is plugged in.

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 05, 2020, 05:57:25 pm
content: Quote from: james_s on January 05, 2020, 05:12:04 pmThe nice thing about LiFePO4 is that 2 cells have more or less the same charging voltage as 3 lead acid cells. You can also get a balancing BMS to be sure, although I'm not sure how common are 2S LiFePO4 balancing BMS.

author: bob91343
author_rank: Super Contributor
timestamp: January 07, 2020, 06:55:21 am
content: I would prefer to get a lead-acid replacement. The old battery has a price tag of $4.95.It's not an important issue; I don't need a battery operated voltmeter and this meter isn't all that useful. I just thought it'd be nice to have it work as original.

author: tautech
author_rank: Super Contributor
timestamp: January 07, 2020, 07:14:20 am
content: Digikey still has Cyclon cells for sale:https://www.digikey.com/catalog/en/partgroup/cyclon/3500

author: Gyro
author_rank: Super Contributor
timestamp: January 07, 2020, 12:56:19 pm
content: Quote from: tautech on January 05, 2020, 07:11:42 amCyclon cells are very unlikely to lose any water. They tolerate very high internal pressures and their vents are set accordingly. The only likely failure mode is sulphation due to long term discharged storage (even then, they are pretty robust and can sometimes recover with long duration charge - until they start pulling current). Treat them right and they will last for literally decades!They're well worth replacing like for like - as tautech's link.

author: BradC
author_rank: Super Contributor
timestamp: January 07, 2020, 02:06:46 pm
content: Quote from: Gyro on January 07, 2020, 12:56:19 pmI've been using them where possible to replace standard SLAs in hard to get at, critical or expensive equipment. I absolutely love them.Yes, they are expensive, but they just seem to keep going, tolerate accidental abuse better than any lead acid I've ever worked with and seem to have a tiny self-discharge characteristic.Worth the price of admission.

author: james_s
author_rank: Super Contributor
timestamp: January 07, 2020, 07:19:12 pm
content: You can get them from lots of places, the link I posted sells them for around $8 each, shop around though, they have been made for decades and are widely available.

author: bob91343
author_rank: Super Contributor
timestamp: January 07, 2020, 10:05:54 pm
content: Nothing for less than about $40, not worth that much to me.

author: james_s
author_rank: Super Contributor
timestamp: January 08, 2020, 03:20:19 am
content: $40 doesn't seem like much money to fix a piece of gear. Hard to get any kind of battery pack for much less than that.

author: Craftsman
author_rank: Newbie
timestamp: June 18, 2022, 06:47:02 pm
content: Sorry for being a bit late to the game but I've actually had good success so far with refilling SLA UPS batteries!I, like others in this thread, have popped the covers off, refilled the cells, and then charged the battery only to find out that the results were far less than expected with little to no capacity recovery. I concur with the general consensus that the batteries were sulphated and therefore, just watering the battery at this late stage will do little to revive the battery.Before giving up on these batteries, I decided to take things further and attempt to desulphate the batteries. I initially used a Foxsur 8A charger with a repair mode which is known to have good success in desulfating car batteries. After a few short hours, the Foxsur charger signed it was done. A quick test of the capacity showed that little capacity was added as the Foxsur ended too soon to do much good (it has a termination point when the battery's voltage hits 15.85V which is fine for a regular flooded battery but these AGM batteries get to 15.85V too quickly).Therefore, I decided to try an Alastair Couper design desulfator readily available on the likes of e-Bay - I upgraded the components and corrected the known published flaw (one of the timing capacitors for the 555 was the wrong value). Initially, to just hooked up the desulfator and let it run and recharged the battery every few hours as the battery ran dead. The constant need to recharge the battery grew tiresome. So, I decided to connected it to a 12V float charger to power everything and let the whole thing run for days rather than hours. After a week, I removed the float charger and recharged the battery fully to see how long the battery could power the desulfator and got a bit more than a day which was a massive improvement over a few hours. I reconnected the float charger on the battery and continued desulfating for another week (so two weeks in total) and did another discharge test and found that the battery now lasted 2 days and a bit. I connected the float charger back on for another 2 weeks and the discharge test now resulted in 4 days. After each discharge test, re-watered the cells.After reconnecting the batteries up to the UPS, the run time displayed on the UPS is now the same as a brand new battery. I completed a discharge test on the UPS and the numbers were very reasonable.I've only completed this on two SLA batteries and both came out great.