Bring Dead Lead Acid Battery to Live Again

Introduction: 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

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

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

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:

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



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    39 Discussions

    Which is considered as waste water in the filled battery ?

    Can you help me with this?

    after restoring battery ,can it be kept if not in use?

    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

    3 replies

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

    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.........

    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.

    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?

    1 reply

    @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

    please guide me how you had done ..please tell me how to repaire dead battery


    Thanks Marek ! Very good method

    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...

    Can we revive battery with no continuity?


    **************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

    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

    1 reply

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

    1 reply

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

    I must say, this is without a doubt the best method to reconditioning batteries available. I have tried some methods in the past but none of them worked.

    Anyway, thanks for the help.