Introduction: Bring Dead Lead Acid Battery to Live Again

Picture of Bring Dead Lead Acid Battery to Live Again

to day we will learn how to bring dead sealed lead acid battery to live again
this method i tried with alot of dead and expired batteries and 90% of them back to work again

P.S : this method may be not bring the battery to full performance of the original condition but at my rate  the battery will work for 50%~70% of it.

you need :

- 3cm syringe
- voltmeter or multimeter
- battery charger or power supply
- crocodile cords "used with PSU "
- Distilled water

For Safety :
use goggles and chemical gloves
don't touch the water came out the battery it's acid  

Step 1: Preparing the Battery

Picture of Preparing the Battery

in sealed battery we will find cover on the top of the battery
just remove it by little flat screw driver like photo
when finish we will find 3 holes covered by rubber caps
now we have to remove this caps too.
ok now we will measure volts of this battery
on my battery it's 0.76 volts only. that's mean the battery is completely dry from inside

Step 2: Fill the Water Inside the Battery

Picture of Fill the Water Inside the Battery

we need in this step to fill the battery with Distilled water to activate the acid again
so refill it by syringe few time until the water come out from all holes  and measure the voltage
u will find it increased by mVolts
that's good

if not don't worry

Step 3: Mix Water With Acid and Charging

Picture of Mix Water With Acid and Charging

after filling the battery with the water we need to make sure it's mixed with dried acid inside the battery to reactivate it again

so first we will charge it with 12 volts DC "i'm using ATX PSU " output is 10Amps
u can use any charger 12V in maximum 9V in minimum

ok now wait 5min until u see bubbles come out from the holes.

if no bubbles come from any of 3 holes u have to reverse negative and positive and wait 1~3min At Maximum (it's Dangerous step don't leave the battery in this condition alone)
ok now u must see bubbles come out from holes too fast like boiling cut off the power immediately and reconnect  negative and positive right again


Step 4:

Picture of

now pull the wasted water from the top of 3 holes by the syringe and let the battery charging
Don't cover holes until it charge to 6.9V u should check it every 1 hour

then dry it out by tissue and cover every thing

Congratulations ur battery is working again

feel free to ask me?

sorry about my bad english!!

Subscribe on my channel on youtube Eslam's Lab if you are intersted in what i'm doing


SunBliss (author)2017-11-02

I tried this method and did not have any luck. Then I tried another method I found online and it worked!

Now I have 2 spare batteries I swap out for my cattle fencing! :)

MehmetŞ2 (author)2015-01-01

I tried this method with copmpletely DRY 12 V/7A batttery.(No liquid inside). Before trying I measured 0,46V from battery. Then I filled all cells with only distilled water(no acid used). Then remeasured: 0,34V. Next I tried to charge the battery by a China made recharger, but it is mcu controlled and did not charge. So I tried to charge it with an adaptor. But again no charge. Because there is only distilled water inside battery and distilled water is pure, no minerals inside, and it is a strong water-resistant. I think to start desulphate battery fiilling only with distilled water is not good idea. there must be an electric flow through poles, but it is impossible when using only distilled water

WayneG49 (author)MehmetŞ22017-10-11

You must mix Epson Salts with Distilled Water, as it's the best way

rick.sego.792 (author)MehmetŞ22015-04-02

not imosible but what I did sounds dangerous but im a rookie and I added regular water not distilled charged at verrylow volts after hour and half I charged my 12 volt for 5 mins at a high power for 24 volts ...then charged regular 12 volts for hour and a half and it worked for 6 batts for me...its how i do it its just a suggestion but be carful wear glasses friend got acidin eye when it was at high charge it built pressure so we let it cool off and charged at regular 12volt 2 amp.........

silentbogo (author)MehmetŞ22015-02-16

It's probably not water, but the charger itself that's causing this to happen. If you have an electronic charge controller, it is set for normal charge cycle(1/10 Ah rating for 7-8 hours). This tutorial worked on 6V battery with 12V charging voltage (4.5-5V higher than normal) and high amperage, so you'll need somewhere around 19-20V to kickstart the process.

There is a technique for lead-acid restoration using pulse-charging. Basically it is the same thing, but instead of reversing the voltage it continuously feeds high intensity pulses to break through corroded layers of Pb.

amiir (author)2017-03-08

hey guys. i have 12V SLA battery and it wasn't use 1 years. after
charging its not save power as it should. the voltage was 3.6V and it
dies after 10Sec. i collect some rain water and clean it with cotton
filter. refill the 6 cells and charge the battery for 5H. in first hour
it takes 0.3 ~ 0.9A and in next hours 2.6Amps. is it normal? what was my
mistake? the voltage is 7.78 now and its not die fast. it can provide
7.78V for a LED lamp almost 3hours. what should i do to make it 12V or
near 12?

WayneG49 (author)amiir2017-10-11

@amir never use rain wayer as it has chemicals. You must use DISTILLED water and Epsom Salts. You boil the Distilled water, then mix with Epsom Salts well. Then you drain old acid from battery and fill all cells with Distilled & Epson Salt mixture into all cells. Then charge till bubbles show and let cool down. Afterwards you close caps or reseal holes for sealed batteries and Trickle charge battery for about 24 Hrs

othmans4 (author)2017-07-23

did someone tried this : --->

sangappa173 (author)2017-02-24

sir i had tried 12 volt 7 ah battery ..but it is not working ...after charging it shows up to 11 volt but within 20 minit it will be down

RahulS500 (author)sangappa1732017-05-26

I know this is a reply to an old post, but since it might be useful to other too I will tell you what I found. I have recovered a bunch of SLAs.There are two different situations I came across.

1) Some of the batteries has around 2-3V for 6V SLAs and 3-4.5V for 12V ones.These are the ones in most cases where you could just fill it with distilled water(avoid tap water unless there is no other option) and just plug it into a charger. But to kick start the process you should add 5-10mL of battery acid from a good Lead-Acid and the charge it intially with a higher voltage charger,like a 18-19V laptop charger @ 5-8A with the caps open.Once you see the water bubbling it means the charging has begun and once you feel the battery is getting really warm.Remove the laptop adapter and connect to your normal Lead-acid charger.You can seal the caps now with some epoxy glue Sulfation is quite low in these types and will recover 60-80% capacity in few cycles.

2) This is for those batteries that are fully driedand have voltage from 0.2V to 2V maybe. These are typically fully sufated and very hard to recover.But its possible unless its bloated or fully shorted out inside.Using a pulsed DC is very effective here aka De-Sulfator.If you dont have one, First add 10-15mL of battery acid.Then fill it with distilled water. You will need very higher DC voltage 48V-60V to kickstart the process. I used a bank of five 12V batteries in series to get it and connect to the fully sulfated ones. It will usually take 20-30 mins to start charging and you might have to wait till you see bubbling in all the cells and the cell is hot. Disconnect it from the high DC Voltage and allow it to cool. Now connect to a regular charger and use. Here only 40-60% capacity is recovered.

If you see any cell where bubbling is very low or nil and the remaining cells are bubbling.It means that cell is very sulfated and needs plenty of cycles to recovered or be desulfated using pulses.

MilindP9 (author)sangappa1732017-05-11

it means your battery has shorted inside so it cant retain the charge

JimK145 (author)2017-04-11

How do I do this properly?

JimD150 (author)2017-02-10


sudhir8014 (author)2016-11-26

Hi...I tried this method with 12v sealed battery and charged it for 12hr with connection source +'ve to battery +'ve and source -ve to battery -ve but it's not charging more than 1V...ways a problem...

NituSunil (author)2016-10-19

Can we revive battery with no continuity?

ChuckN15 (author)2016-09-03


**************PERSONAL PROTECTIVE EQUIPMENT**************

You're English is just fine, thanks mate. I might try this out when I have a bad battery but lately the last couple of years I haven't had any problems and I use second hand batteries and second hand batteries are so cheap now that it isn't worth trying unless you're pretty broke desperate and already have the tools you need. Playing with acids is also pretty dangerous for your health and can cause severe respiratory problems and nasty deep burns so try to do this outside where there is open air. Have a garden hose next to you on standby or a full bucket of water just incase you get it on your face or eyes so you can flush it away. Try not to inhale acid fumes because you could end up paying for it later. But like I said if you have no other option and you have the tools then go for it. P.S. paper respiratory masks will not help because they build up harmful toxins because they are really only for dust and mild organic fumes if that. Use a real carbon filter mask and fully closed eye goggles when handling acids and wear full cover clothing and apron ($5 cheap disposable apron) and fully closed shoes in case of spills and skin contact. If you have any battery acid contact your protective clothing just simply remove your clothing and place in trash "do not bring it inside" or leave it near kids or pets and shower immediately and do not rub your face and eyes until you have thoroughly wash your hands. This ideas of fixing batteries is really great but also remember safety. Sometimes it's not worth the trouble over a second hand reconditioned battery replacement for $50 and sometime less if it's just a good second hand battery. Personally I rather not inhale battery acid fumes or get it on my skin or eyes but when your desperate maybe look up some safe operating procedures before you become ill or injured! Nothings simple but safety is paramount but unfortunately third world countries tend not to waste any time or money on safety because it doesn't make them money. In a modernized country you have no excuse so do the right thing by you and others. I hope this has been helpful and remember to implement a plan and safety procedure before attempting to handle hazardous substances or using dangerous tools and machinery. You'll be glad you did

CyberR (author)2016-07-01

Persiverance+your guide+new charger = restored battery

The Honda battery is now holding an almost full charge, roughly 90-95% but good enough for me. Had to replace the original charger as it failed to power up. After further investigation it turns out the new charger can only charge batteries between 20Ah to 50Ah max so anything below this and the charger thinks the battery has failed and cuts the charge.

Battery charged up, connected up 2 20W hallogen bulbs and both are still bright 20mins later a big thank you, Eslam Eldeknawy

Eslam Eldeknawy (author)CyberR2016-08-15

happy to hear that :)
good luck

DminkiD (author)2016-07-25

does this method work on 12v 200AH sealed Batteries?

Eslam Eldeknawy (author)DminkiD2016-08-15

give it a try if you have no way to fix it
but don't charge on more than 20 amps charger

CyberR (author)2016-06-30

Found a Honda GTX9-BS battery with a confusing Rating (to me it is).

Reads like this
12V 8Ah
8.4Ah(20HR) / 135A (CCA)

Also found a generic 12v 5Ah SLA

Generic is now charging as normal now. The Honda is not. Charges for 20~30 mins then charger says its full. When tested it only lasts 3~5 mins tops. By the look of it it may have had it but, until it stops charging altogether (or explodes on me, in which case I won't have a choice), I'm not giving up.

Great 'ibble!!!

CyberR (author)CyberR2016-06-30

Doofenschmirtz here forgot what CCA was. Confusion over, it cranking amps. As soon as I hit google I remembered before i could type it in.

(Hey its late and I'm tired) (=)

JewelJaskot256 (author)2016-06-24

I noticed that a possible workaround if you cannot find DI water is to drain some acid out of a dead flooded battery and this will be good enough.

Richard177 (author)2016-06-24

We all have one or the other product that runs on a battery and hence the need for changing the EZbattery is an inevitable affair. When your battery gets exhausted it goes without saying that you need to replace it soon.

taktrashe (author)2016-05-16

it is interested me !! i do it .

conundrum2142 (author)2016-01-23

Interesting. just an aside, if you use anything other than DI water you will get chlorine and possibly H2S emitted during charging.

I noticed that a possible workaround if you cannot find DI water is to drain some acid out of a dead flooded battery and this will be good enough.

YMMV, this is a last ditch gonna-chuck-it-in-the-bin fix but it seemed to help here, now charging at 11V 0.55A whereas before it was drawing >5A at 6V

nolway (author)2016-01-03

Hi Guy's I have been trying to revive Trojan 27 TMH deep cycle batteries for 10 day's now with distilled water and Epsom salts have only been able to get 1 battery up to 10.4 and the other one to 8.6 this was from day 3 until now .What else should I do 2.2 amp hour and trickle chargers used.

dkrall (author)2013-12-02

I hope you "weared" the glasses because you didn't use the gloves you mentioned

AnthonyH41 (author)dkrall2015-11-11

funny guy... my hands are meeellllting :D

Eslam Eldeknawy (author)dkrall2013-12-03

i didn't because i knew what i'm doing
but i just mentioned for people maybe don't know what they doing or trying fix batteries for first time.

safety 1st
good luck and thanx for reading my instructable

shyameetu (author)2015-07-29

After boiling battery electrolyte, reconnect the positive and negative right but at what voltage and ampere settings? Wouldn't it reboil the electrolyte??

sami.hussien.144 (author)2015-04-10

I had a problems when I fill the 3 cells with waters and start charging the bubbles come outside then after each hours the valtage coming up after 14 hours stop charging then try to use battery in the beginning start very good then becom losing power quickly whats the reason ?

Macattacku (author)2013-12-06

Im just saying u showed a valve regulated battery. Unless u treated it like crap they never go dry, ever. They recycle all thier water. Adding water sometimes seams to help for a while but they arent meant to be flooded in the first place, u will dilute the acid, it would have worse voltage curves.

MikB (author)Macattacku2013-12-07

I've had mixed success with this for reanimating old SLA batteries.

VRLA (Sealed) batteries SHOULDN'T dry out, because they have clever technology to recombine any outgassed hydrogen/oxygen back into water. This doesn't always work, so the cells vent. That's why those rubber caps are there. That's a one way ticket out of there for the hydrogen etc.

Some "float" chargers seem to eventually destroy the battery by a continuous slight overcharge, which dries the battery and raises its internal resistance. Water helps these.

For those that are chronically flat/undercharged, they are sulphated, and will barely accept a charge. You have to get pretty extreme with them to get any life from them, e.g. charging a 12v battery at 50volts (CURRENT LIMITED!) to get anything to move. As soon as they start charging, you have to back off on the crazy-charge!

Replacing the water is a last ditch hack to get some life back, and it works for a while. The bubbling and output of liquid is a bit hazardous, you have to think carefully before "mopping up" any of that because it will damage cloth, clothes, carpet :)

And no smoking!

Eslam Eldeknawy (author)MikB2013-12-07

thanx MikB for explaning

thanx for ur reply but i just said they are dead batteries and expired
Mfg date is 2005 i they were working but stopped long time ago so i tried to charge them and nothing happened they give me .9v after charging

and i flooded them then i pulled residue water out so they are not flooded
about voltage curves i didn't measured but i'm using them in rechargeable emergency light and it works fine for 2 hours discharging .

liquidhandwash (author)2013-12-03

Ive had success with car battery's that are starting to die, when the engine gets slow to crank I overcharge the battery with a 50 watt solar panel and no regulator for 3 or 4 days they can go as high as 16 volts. I currently have a battery in a diesel ute that "died" 3 years ago, It it has only had the solar panel treatment twice.

good to hear that but next time be careful
to fix car battery u need hydrometer to measure relative density of the liquid inside the car battery
the optimum density should be between 1.16~1.18

if the battery is shorted u can clean it from inside
here in egypt some experts use sodium bicarbonate and water to clean the battery sheets

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