Renew Your Dead Car or Bike Battery

Now you can save you thousands of bucks that you might spend on buying car or bike or just any lead acid battery even when its not needed. Lead Acid battery plates develop sulphur with aging and this blocks current leading to low voltage and a time comes when battery is no more able to maintain 12v and car does not start.

I have tried this trick on my car battery which went dead few days back, just 10v was left in it and was going down to 4v on using self. First I tried charging it using battery charger for one whole day and night but I found as soon as I remove it from charging, it would go to 10v at once. So battery was dead, there was no reaction (bubbles) in one of the cell. I was about to change my battery then found this tip and it worked for me

The real thing:
When you are not able to recharge the battery and it won’t maintain 13v then do this.

1. Open all the caps (from where you fill water) of cell and drain the acid. (You can use this acid to remove algae). Please do this cautiously, wear surgical gloves and goggles to protect your eyes and hand from acid.

2. Take an empty 600ml plastic cold drink bottle, fill it with distill water and add 2 teaspoon of magnesium sulfate in it. Shake shake shake! shake it well untill all the salt gets dissolved in distill water. You can get magnesium sulfate from people who supply chemicals in school labs.

3. Fill each cell with this magnesium sulfate solution you just prepared, don’t overfill, just about 0.5 inch above plates is good. Tap the battery from each side so that air bubbles trapped in plates escape.

4. Don’t put the caps back, leave battery open and put it on charging. I used 5 Amp charger for my 35 Amp car battery. Charge it for atleast 24 hours. Use atleast 10% current for charging, for example your battery is of 12v and 65 Amp then use atleast 6.5 Amp current and 13.8V for charging. I would recommend slightly higher of about 8 or 9 Amp.

5. Remove battery from charging and check voltage. Wear your goggles and peep in cell using a torch to see tiny bubbles coming up from each cell plates. This indicate that your cells are working! If you don’t see this then your battery needs more charging. If you do see bubbles and battery voltage remains constant between 12.6 – 14v then you just saved your battery and it can be used in your car now!

The magnesium sulphate solution will turn into acid when battery is charged so you don’t need to add acid later. If you feel electrolyte level has gone down after this long charging, you can add distill water. But remember don’t overfill the cells as overfilled cells with experience slow charging.

Disclaimer: Use this tip at your own risk, in no case I will be held responsible for any accidents or loss caused by trying tip described above.

Mohd. Hashim Khan

I work as a freelance web designer and developer and enjoys fiddling with machines and electronics stuff. I am also working as a part time computer teacher at Aligarh Muslim University. I share my knowledge on various topics here so that others can make use of it and take benefit from my experiences.

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6 Responses

  1. Rey says:

    why is that when I added the epsom salt solution and after charging it overnight, the voltage of the battery drop down from 10 to 8 volts?

  2. admin says:

    Rey can you tell few details like type of battery (car / bike) what Ah rating the battery and and what rating charger is.
    Is the battery heating?
    And can you see tiny bubbles in EACH cell?

    Few reasons of dropping of battery voltage on charging are:
    One of the cell in battery gone bust
    Charger is faulty or you forgot to switch it on 😛
    You did not connect the battery properly to the charger. (Terminals should be clean, use sandpaper.)

  3. carl says:

    can battery be saved even after being frozen then thawed out

  4. Ron Kotula says:

    So can I use Epsom salt or do I have to use magnesium sulfate that I can purchase from a chemical supplier that sells magnesium sulfate to schools for chemistry classes. Thank you so much for your help.

  5. Ron Kotula says:

    Thanks for your help. My question is, when renewing a dead car battery, can I use Epsom salt from a grocery store or do I use magnesium sulfate that I can purchase from a chemical supplier that supplies magnesium sulfate to schools for their chemistry classes

  6. Mohd. Hashim Khan says:

    Magnesium sulfate and Epsom salt are the same things so you can use Epsom salt bought from grocery store provided it’s of good quality and not adulterated with some other salts.

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