How much Epsom salt do you use in a battery?

How much Epsom salt do you use in a battery?

Epsom salt is commonly used in cars to recharge or recondition dead batteries. Take a look as we see how the salt is used and the safest ways to recondition a dead battery.

A car battery is a component that is easy to fix and maintain and every car owner should know to navigate around. When wake up one morning and find a dead battery, it can be very frustrating. Instead of buying a new battery, there is a cheaper and a much more home friendly option: reconditioning. The process of recharging or reconditioning it is straightforward and literally anybody can do it provided you follow the steps correctly. However, there are times when a recharge process won’t work, and this occurs in the following conditions:

  • The battery is too old (over six years) and cannot any more recharge. You will notice that the battery does not hold charge as well as it did
  • There is a short circuit in the battery. Here, you have no option but to get a new one
  • The battery metal rods are damaged beyond repair

If your battery suffers any of the above, new replacement is imminent.

Symptoms of a dying battery

There is no need to wait for the battery to die when you can look out for some signs of a dying battery. Look out for the following symptoms

Dim lights and other electric faults

Since the battery powers all the electronic components of your car, they will be the first to suffer when the battery power is low. It may start with your headlights dimming or not being bright as they were. You may also notice the interior lights and dash lights being dimmer than usual

Engine starts slowly or weakly

If you find that it is taking longer for the engine to come on when you turn the ignition, this is a sign of a dying battery. The engine does this because there is little power being provided to it. Usually, this sign is the last straw before the engine finally dies

Check engine light is on

Now there could be a number or reasons this light comes on. Among the top reasons is a dying battery. If this light is on and there is another symptom showing, there is a high chance that the battery is the problem

Corroded metallic parts on the battery

When a battery is dying, the metallic parts tend to corrode. To identify corrosion, look for an ashy white substance on the metallic parts of the battery such as terminals. If there are white deposits, your battery is about to fail you

Bad odor

A bad odor is usually not a good sign because it means the gases in the battery are leaking. These gases leak when there is a short in the battery or some damage inside. There will be a rotten egg smell when you open the hood. When this happens, take the car to the mechanic immediately. There is a high chance you might need a new replacement.

How much Epsom salt do you use in a battery?

When reconditioning the battery, there are a lot of items you will need, with Epsom salt being one of the most important tools. Other items you will need include: protective gear, a battery charger, funnel, screwdriver, distilled water, old toothbrush, baking soda in powder form and a voltmeter. For you understand the amount of salt needed, you need to understand the recharging process.

Wear the protective gear

The protective gear should include gloves, a mask and goggles. These protect you from the corrosion properties of sulfuric acid that is found inside the battery. After wearing them, make a water and baking soda solution in the side.

Remove corrosion on the terminals

Use the water and baking soda solution to clean the ashy white terminals by scrubbing with the toothbrush. Scrub until the white deposits are completely off. Wipe and leave to dry for a few minutes.

Take a voltmeter reading

Once clean and dry, connect the voltmeter to the terminals and take down the reading. The red wire goes first into the positive terminal then the black cable goes in into the negative terminal. The reading should be anywhere between 10 and 12.6 V. If the reading is 12.6 or higher, your battery is fine. If the reading is 0, this indicates an electric problem inside the battery meaning you will have to replace it.

Clean out the electrolyte

Now that we have confirmed our battery needs recharging, get a screwdriver and open the battery caps. Once open, pour out the electrolyte – sulfuric acid slowly and safely since it is highly corrosive. When completely empty, pour in half a kilo of baking powder to neutralize the acidic environment. Add a few cups of the water to the baking powder and shake for about one minute. Pour out the solution into the same bucket.

Pour in 120 grams of Epsom Salt into boiling distilled water

Here, get a fresh and clean bucket and mix in 120 g of the salt with about a liter of distilled water. Mix the solution until the water is clear and there are no remaining solids in the mixture. Refill the open cells with this solution.

Charge the battery

With the solution inside and cell caps closed, charge the battery using the battery charger. Connect one end to the positive terminal (red) first and the other end to the negative (black). Turn the charger on and leave it charging for 36 hours. After this time has passed, test the battery using a voltmeter. The battery should read between 12.43 and 12.6 V indicating that it is in now superb working condition.

Is there anything else that can be used apart from Epsom salt?

If there is no Epsom salt around you, other chemicals can be used for this process. Copper sulfate is a blue powder than can be used in place of Epsom salt. Aluminum sulfate can also be used but should be used in equal amounts with distilled water. Epsom salt is however the most common and easy to find product.


  1. Avatar Keven Pruneda February 6, 2021
  2. Avatar Jule Cafaro February 6, 2021

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