How Do You Rejuvenate An AGM Battery With Only 2 Simple Methods?

Are you thinking of throwing away the old AGM battery? If yes, stop right there! If you can rejuvenate them, these sealed Lead acid batteries might last more than a year. But how do you rejuvenate an AGM battery? 

Pair the discharged AGM battery with a good one and start recharging it. Once the old battery gains adequate voltage, hook it up directly with the charger.

Trust us; you won’t need professional help to revive the batteries. Equip up with your cables, batteries, and charger, and give it a go!

Can You Rejuvenate AGM Batteries? 

Can You Rejuvenate AGM Batteries

AGM batteries are well-appreciated for their high power and long life span. Due to their internal resistance, you will rarely need to maintain them. But can you recondition it once it’s old?

We have performed several experiments on old AGM batteries just to be sure. At first, our battery had 450 Amp CCA in the load test. After recharging it once, we got around 500 Amps. So, yeah, reconditioning the AGM battery is possible.

Does AGM Battery Undergo Self-Discharge?

Yes, AGM batteries do undergo self-discharge. Self-discharge is a natural process in which a battery gradually loses its charge over time even when it is not being used. The rate of self-discharge depends on the type of battery and environmental conditions, but generally speaking, AGM batteries tend to have higher self-discharge rates compared to other types of lead acid batteries, such as wet cells or gel cells. This means that if an AGM battery is not being used over long periods (several months or more), it will need to be recharged frequently to keep it functioning properly.

Tools You Need to Rejuvenate AGM Battery

Tools You Need to Rejuvenate AGM Battery
  • Cables
  • Charger 
  • 12.2V Good Battery 
  • Voltmeter
  • Watch

How Do You Rejuvenate An AGM Battery? 

How Do You Rejuvenate An AGM Battery

AGM batteries are pretty expensive. We bet you don’t want to throw it before you can utilize its maximum potential. 

So, let’s check two basic methods to rejuvenate the AGM battery now!

Method 1

Get the latest AGM charger. It features a modern desulfation setting to recondition the battery. 

  • Simply hook it up with the batteries for external charging. You can also use it for other lead-acid batteries. 
  • It features a specific ring terminal for additional external attachment. 

Don’t worry about quality, as modern AGM chargers can magnify the storage battery’s maintainer.

Method 2 

In this procedure, you have to use a fresh battery. It will trick the regular charger into reconditioning the discharged AGM battery.

Step 1 

  • Take a fresh 12.2V battery and hook it up with the discharged one. 
  • Couple the fresh battery’s positive end with the discharged positive edge. Similarly, hook up the negative ends together as well.

Step 2 

  • Take a regular charger and hook it up with a fresh battery. Let it absorb the charge for several hours. The discharged battery will also pick up charges throughout the process.
  • The discharged battery might warm up if the charge uptake is successful. However, discontinue the charging process if the battery heats up.

Step 3 

  • After some hours, check the voltage of the AGM battery. Once the discharged battery voltage reaches 10.5, disconnect the charger. If you are using a 10 Amp charger, it will take a minimum of 2 hours.
  • Disconnect the discharged battery from the old battery as well.

Step 4 

Now directly hook up the old battery with the charger for hours. Keep on charging until the battery is full. Repeat this whole procedure until your battery is functional again!

Safety Precautions To Consider Before Running The Test 

How Do You Rejuvenate An AGM Battery? 

First, go for a thorough battery check before running the test.

  • Clean up the battery with a wiper.
  • Run this test in an open space.
  • As this test involves acid, it is best to go for safety gloves & goggles.
  • Keep a voltmeter nearby to check the battery status over time.
  • Use a timer to keep track of time.
  • If the AGM battery heats up during the process, disconnect the charger right away.
  • Lastly, never leave the battery unattended while you charge it.

You can also read – Can I charge an AGM car battery with a solar panel


  • How many amps do you need to charge the AGM battery? 

We recommend using a 10 Amp charger for 2 to 8 hours per the depletion rate. You can go for a high amp charger, but it might damage the battery early on. Thus, a low amp (1 to 10) charger is indeed the best option.

  • Should you purchase a special charger for The AGM battery?

A special charger isn’t really mandatory for AGM batteries. Just grab one with 12.6V to 12.8V power from the local hardware store. However, if you have the budget for an intelligent AGM charger, go for it.

  • How to detect a sulfated AGM battery? 

It’s nearly impossible to identify a sulfated AGM just by external observations. Get a multi-meter and measure its standing voltage. If it’s below 12.6V, then the AGM battery is sulfated. 

  • How long will you need to de-sulfate an AGM battery? 

Complete desulfation of the AGM battery will need around two to 7 days. You must charge the battery during this time for lead sulfate reduction in the solution.


We believe our content has guided you through – How to rejuvenate an AGM battery. It’s indeed easy once you pile all the necessary tools. So, Why won’t you give your old AGM battery a go before throwing it away? After all, it can save you a fortune!

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Marcelo Araujo-Xavier

Hi, Marcelo Araujo-Xavier is here! I am the author of Batteryhint. I have been working in the battery industry for over 20 years and have a passion for helping people find the best battery for their needs. I have personally tested and reviewed hundreds of different batteries. I'm certified by the International Association of Automotive Battery Manufacturers. I have always been interested in batteries and how they work, so I decided to start this website to share my knowledge with others. I hope you find the information on this website helpful and informative. I will be regularly updating this website with new resources, If you have any questions or comments, please feel free to contact me. I would love to hear from you and help you find the best battery for your needs.

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