My car battery is dead. A friend told me about “battery reconditioning” to fix dead cells. Is this actually possible? How can you fix a dead cell in a car battery?

Matt Terzi · Updated on Feb 3, 2022

Reviewed by Shannon Martin, Licensed Insurance Agent.

Dead car batteries are super frustrating and expensive to replace. I’m sorry you’re dealing with this! While you can fix a dead cell in a car battery by reconditioning it, it’s extremely dangerous. Acid burns are awful, so try this at your own risk and please be careful! That said, if at any point you feel uncomfortable or unsure, contact a professional to complete the process.

Here’s what you’ll need:

Chemical-resistant protective wear (goggles, gloves, and an apron at least!)

Flathead screwdriver

Voltmeter

Battery charger

Two big buckets

Funnel

Toothbrush or steel wool

One gallon of distilled water

One pound of Epsom salt

One pound of baking soda

And the steps:

Safety first. Make a cleaning solution of 2 parts baking soda and 1 part water. Put on all of your protective gear and make sure the room is ventilated.

Use your cleaning solution and the toothbrush to clean the battery terminals and scrub away any corrosion. Wipe the freshly cleaned terminals dry before continuing.

Use your voltmeter. If the voltage is between 10V and 12.6V, you can continue. Anything below 10V means the battery can’t be reconditioned.

Remove the battery’s cover, then remove the cell caps underneath using the flathead screwdriver. Now, slowly and carefully empty the cells into a bucket, adding baking soda to neutralize the acid.

Pour your cleaning solution into the cells, then put the cell caps and battery cover back on. Aggressively shake the battery for one full minute. Empty the battery cells into the waste bucket after.

Mix four cups of distilled water and four ounces of Epsom salt, and stir until the water is clear. Then, use your funnel to refill each cell. Cover the battery and aggressively shake it for another full minute.

Set the battery up in a safe area and remove the battery caps in case an overflow happens.

Connect your charger and start it at a speed of 12V/2 amps. It’ll take 36 hours to recharge.

If the voltmeter reads between 12.4V and 12.6V, install the battery and try turning on your headlights. Test it again a few minutes later, and if the voltmeter says 9.6V, your battery is reconditioned.

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