How to Recondition a Sealed Car Battery?

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How do you recondition a sealed car battery? How can you know if it is time for this type of service? How long does the process take and how much is it going to cost? These are just some of the questions that people ask themselves when they find out that their battery is not working as well as it should.

So, how to recondition a sealed car battery? It is better to recondition your sealed batteries than to buy new ones. Reconditioning your sealed battery can be done by using Magnesium sulfate or Epsom salt solution process. All the necessary equipment will be needed for this process like a bucket, distilled water, funnel and syringe or dropper, gloves, and goggles.

There are many different types of batteries, but in most cases, the best option is to have your battery serviced by an expert. This article will give you all the information needed about reconditioning sealed batteries so that you can make an informed decision on what steps to take next.

I am going to show you how to recondition a six-year-old battery that has been sitting around for a long time. It’s pretty badly sulfated.

To do this, first I will show you how to remove the stickers and find any hidden ports beneath them.

How to Remove the Stickers From battery And Find Any Hidden Ports beneath Them?

It’s hard to find a hidden port on your sealed car battery when it has a sticker over it.

The solution is simple, just peel off the sticker and you’ll be able to see all of the ports. Let’s see how to remove the sticker.

Necessary Tools:

  1. Ordinary hairdryer
  2. Pocketknife

To remove decals, we use a hairdryer and a knife.

First, warm up the decal with the hairdryer. Carefully peel it off. Then stick it to the side of the battery. This will have all of the maintenance and reference codes that came with your battery on it.

Notice that once the decal gets warm, it comes off the battery easily. Make sure to keep the hairdryer on it at all times.

You’re peeling it all that way there you won’t ruin it now just stick the decal on the side of the battery.

It can stay there always for reference, as you can see where our service caps were hidden before and are now exposed because of the decal coming off.

We’re going to take a hammer and a sharp tool called an awl. We’ll put oil on the top of the battery, and then we’ll use the hammer to raise up that cap. That’s all there is to it.

Once we have all six caps loosened up this way, we simply set the battery on a stand and remove the caps.

You will need to use these caps again after you service the battery. These caps were tight, so be careful when removing them.

Now, that the caps have been removed.

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How to Recondition a Sealed Car Battery?

You’ve just purchased a new car and it comes with a sealed battery. The battery is guaranteed to last for years, but you’re not sure if the guarantee will hold up.

Sealed batteries are supposed to last as long as your car does, but what happens when they don’t? It’s important to know how to recondition them so that you can save money by extending their life.

Follow these steps and tips on how to recondition a sealed car battery so that you can keep your vehicle running longer.

We are going to do a few tests. You need to pay attention because this is important.

  • The first thing we are going to do is take a small flashlight and check the level of the electrolyte in the cells. We don’t add electrolytes until we service the battery with chemicals, then we top it off. If it was necessary that particular battery was not low on electrolyte, it just sulfated from being unused for years. But we have to check the cells just in case they need more fluids too.
  • The next thing we need to do is take a hydrometer and measure the specific gravity of each battery. When you measure the specific gravity, you will notice that some batteries are in bad condition. This is because sulfation can make them weaker. We will need to check each battery, though.
  • To find out how strong the battery is, we read the voltage in each cell. We start with the positive terminal of the battery. Then, we go to the next cell and do it again. We read to see if there are at least two volts in each cell. If there are not, then that means that you need a new battery or your cells are not working well anymore. When you want to test your battery, make sure you use a voltmeter and test probes so nothing will happen while testing it.
  • Now we’re going to do the test on the battery. Take the positive wire and put it on the positive terminal of the battery. Put your negative wire on a negative terminal of the battery. We read our meter first and see that this is a good indication that our battery can be brought back to life because it is reading 12.5 volts. We push the load test for 10 seconds, and it drops way down into yellow but then comes right back up into green; this is another good indication that our battery is recoverable! Whenever you attach cables to a batter, always put your positive cable on first and remove it last so you avoid making sparks around batteries (because they store hydrogen gas). Sparking around batteries can make them explode. So, be careful when attaching and detaching cables from the battery.

Step-by-Step Guide to Reconditioning a Battery

How to recondition a car battery is actually easy if you know the right steps. The most important thing to remember is to test your battery with either a multimeter or voltage tester (such as the one mentioned above) before starting this process. This method doesn’t work for all types of batteries, and you should never attempt it on a battery that registers bad voltages when tested.

If the battery in your car is very old yet still functional, then reconditioning it might be an excellent option for you.

Necessary Tools:

  1. Sealed Battery
  2. 400ml Distilled Water
  3. 200g Epsom Salts
  4. A Syringe or Dropper
  5. A Battery Charger
  6. Protective wear
  7. Steel wool or battery terminal cleaner
  8. Flathead screwdriver
  9. Funnel

If you really want to get the most out of your battery, here is a step-by-step guide on how to recondition a battery.

Step 1:

A battery only has a certain amount of charge in it. To see how much, you can test it to see if it will work or not. If the battery registers at around 12 volts on a voltmeter, then you might be able to bring your battery back to life by reconditioning it. But if the voltage is under 10 volts, then we do not think we can help you bring your battery back to life.

Step 2:

To recondition a sealed car battery, heat up some distilled water with Epsom salts until it’s 150 degrees F. Then, you should dissolve 7 or 8 oz. of Epsom salts in the water and remove it from heat.

Step 3:

Remove the caps from the battery. You need to find “shadow plugs” (little covers) on the battery. They will cover holes in the battery. You might need to drill through them with a drill and some water.

Step 4:

To make the battery work, you need to take the fluid out and put Epsom salt in. You need a funnel for this.

Add distilled water in small amounts until you’ve reached the proper level inside of the cell or cells that need refilling. Then, add 1 teaspoon (5ml) of baking soda per gallon (4 liters) of freshwater added to your battery’s electrolyte solution and allow your mixture to absorb into each cell for at least 15 minutes before topping off again if necessary.

Step 5:

Put plugs in the holes that are drilled or replace the caps on your battery. Shake your battery to make sure the Epsom salt solution is well distributed.

Recharge your battery with a slow charge for 24 hours. Then put it back in your car.


If you’re looking for a way to recondition your sealed car battery, then this guide is just what the doctor ordered. We’ll be covering all of the steps in detail so that you can learn how to take care of your batteries and get them back up and running again! Good luck with restoring those dead cells.


Can I recharge a completely dead sealed lead acid battery?

Yes, however, if your battery is completely dead, it may need to be replaced.
As batteries discharge, the voltage decreases while the internal resistance increases causing a drop in current flow. Eventually, some cells cease to work altogether due to plate sulfation.
Once this happens, there’s no way of preserving or restoring them with any type of re-energizing process without replacing them.
If your battery is not completely dead, then it’s possible to recharge with the right charger.
However, as you continue to recharge a completely dead sealed lead acid battery, there will be less capacity in the device because of internal resistance and self-discharge increasing.
If you have a completely discharged sealed lead acid battery that has been sitting for too long without being charged, you should dispose of it properly because it may be hazardous.
If the battery is completely dead and has not been used or recharged in a while then that means that some cells have stopped producing voltage due to plate sulfation.
This will reduce capacity but if there are still working cells they can be recharged.

Does battery reconditioning really work?

Yes, battery reconditioning does work. New batteries are expensive, but the old ones are not too bad for your car that needs power. The condition of a reconditioned battery is good enough that it can get the work done for you, but many people still prefer to have a new one.
The life span of a new battery is about 1 to 3 years. Most batteries wear out because one or more cells go bad. Reconditioned Batteries-Many car owners prefer to use reconditioned car batteries over new ones because they are much less expensive.

Does Epsom salt really work on batteries?

Yes, Epsom salt helps batteries. Epsom salt dissolves the sulfates that develop on the battery plates. This will increase battery capacity. And if conventional means to mitigate sulfating and loss of capacity have failed, adding other elements to the chemical reaction will probably not have a lasting positive effect.

Are sealed car batteries better?

Yes, sealed car batteries are better. Sealed car batteries are better than regular car batteries because they require less maintenance. They can withstand different weather better and charge faster.


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