How to Recondition a Car Battery at Home

You could save a lot of money by reconditioning a car battery at home. The new car battery can be pretty expensive, but reconditioning your old battery costs you nothing. And if you are really good in this skill you can also offer a service to your friends or neighbors who are facing the same problem.

Before you learn the technique, you need to understand the type of car battery type.

3 Major Car Battery Designs

1.) Flooded Battery

A flooded battery is sealed, meaning that there is no electrolyte in or outside of the battery. When a flooded battery is discharged, the acid in the battery leaks out of the battery and into the cell. This can be dangerous because acid is very corrosive and can damage surrounding components.

A flooded battery can be recharged by disconnecting it from the socket and immersing it in a container of distilled water. This type of battery should be charged only when the vehicle is turned off.

2.) Valve Regulated Lead Acid (VRLA) Battery

This battery has a compartment containing electrolyte. When the battery is discharged, the electrolyte is pushed outside the battery’s compartment and into the cell.

To recharge this type of battery, you must disconnect it from the socket, add distilled water to the cell, and then reconnect it. VRLA batteries can store a large amount of energy, have a longer service life, and can handle higher discharge rates than other batteries.

3.) Lithium-Ion Battery

This battery uses a solid-state chemistry, and unlike other types of batteries, the electrolyte does not leak out of the battery. This type of battery is environmentally friendly because it does not use any hazardous chemicals during manufacture. Lithium-Ion Batteries can be recharged at home or in a vehicle. This battery is commonly used in hybrid or electric cars.

If you have a vehicle equipped with an internal combustion engine, it is always important to have a working automotive battery. If the battery dies, the vehicle will not start. Battery failure can be caused by a number of factors, including corrosion, a broken separator, and bad connections.

You can avoid this by reconditioning your car battery yourself without having to pay for an expensive battery replacement.

How to Recondition a Car Battery at Home

It is important to check if your car has an AGM or GEL battery, because these two batteries need no maintenance. This guidance is focus on 12-volt lead acid battery, here are the steps you need to follow:

1.) The First Step is to Test the Battery

The battery should have 12 volts on a voltmeter. If the battery voltage is below 12 volts, then the battery can be reconditioned to restore normal function. If the battery is under 10 volts, it needs to be replaced. To check the battery’s voltage accurately, you need a car battery tester.

2.) Preparation of Electrolyte Solution

In the battery, replace the electrolyte solution with distilled water and heat it to boiling temperature. DO NOT add gasoline or any other organic solvents to the water. A solution needs to reach 150 Fahrenheit, but avoid the extreme heat of direct sunlight.

3.) Removing the Battery Caps is the Third Step

We must first remove the cell caps from the batteries. This is done by wiggling the plastic tabs on the caps and then pulling the caps off. Wearing a glove is advisable because you’ll be handling a lot of battery acid.

A sealed battery type requires locating and removing shadow plugs. These plugs will also need to be removed for the battery to flow properly. AGM and GEL batteries should not be used, because this is not the type of battery you need to recondition.

4.) The Fourth Step is to Replace the Battery Solution

Drain out the current electrolyte solution and replace it with the new electrolyte solution you have prepared. Allow the battery to drain completely before charging it, this can take anywhere from a couple of hours to a couple days.

After the battery has been drained, it is time to fill the cells back up with a new electrolyte solution.

Fill your refill bottle with electrolyte solution and inject it into each battery cell with a small plastic syringe. Allow the solution to flow through the cells and flush out the leftover electrolyte.

5.) Battery Charging

If your battery is almost drained then go ahead and charge it. Make sure that the charger does not over charge the battery. Check the charger’s manual for proper charging instructions.

6.) Disconnect the Battery

Once the battery is all filled up and charged, disconnect it from the charger and allow it to drain completely. This is a crucial step because overcharging can shorten the life of your battery. Do not charge your battery more than once a day or it will overheat and blow a fuse.

7.) Finish by Cleaning

Once you’ve finished reconditioning your batteries, it’s time to clean them up and dispose of any leftover fluid or electrolyte solution. The best way to clean off any leftover fluid or electrolyte solution is by adding a small amount of water and cleaning it off with a paper towel.


It is not difficult to recondition a car battery at home. The reconditioning process outlined here should only take a short time, depending on the capacity of your battery and the number of battery packs you have. Once you’ve finished reconditioning your batteries, you’re ready to mount them back into the vehicle and enjoy them for a long time.

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