DIY Battery deSulfation

The Science Behind Lead Batteries

Lead-acid batteries work by generating electricity through a chemical reaction. Lead and lead dioxide on the battery's plates react with sulfuric acid in the electrolyte to form lead sulfate. Over time, this lead sulfate can crystallize and prevent the battery from recharging. This is generally evident by a white coating on the plates. Sulfated batteries are weak and hold little to no charge at all. Desulfation is the process of reversing this process to refurbish batteries back to their original state. This technique can take some time to break down the crystals formed on battery plates, but can be very effective.

Batteries that have sat unused for long periods of time such as those in unused planes, boats, or cars are prime candidates for his method.

Desulfate Process

In order to desulfate a battery, owners must remove the lead sulfate buildup. This is impossible to simply clean off; the only effective removal method is to use magnesium sulfate. Fortunately, magnesium sulfate is readily available, known as Epsom salt. This process is very simple and only requires Epsom salt, distilled water, a regular lead-acid battery charger, and following a few steps.

1. First, put some clean, dry Epsom salt into a dry cup. For a regular-sized battery, measure approximately 10 teaspoons.

2. Next, heat up some distilled water to near boiling and add it to the Epsom salt to create a thick liquid. The water should be just enough to dissolve the salt. Stir the mixture thoroughly until the salt dissolves completely.

3. Pour the liquid mixture equally into each cell of the battery and top off the battery if necessary.

4. After the battery is covered, hook up a regular charger and set it for high amps. Do not use a smart charger because it is important to have the readable meter. The meter will read "zero" or "charged." It can take several minutes, depending on the amount of sulfation, for the chemical reaction to begin to take effect. Watch the meter move up to full current slowly, and then switch over to low current until the battery is fully charged.

5. Once the battery is charged, discharge the battery and then charge it on low current again. This second step helps the magnesium sulfate eat away the lead sulfate. Once it charges the second time, it should be reliable and ready to go.

The desulfation method described here works up to five times on any given battery to extend the lifetime by several months, or years in some cases.

Safety Tips

When working with batteries and chemicals, it is important to keep safety at the forefront. Before working with batteries, remove all jewelry or metal watches and belts. When a battery is charging, it creates hydrogen gas, which is very explosive. Always use safety goggles and wear clothing made of synthetic materials such as polyester rather than cotton, which sulfuric acid may damage. Always take precautions to keep children and pets away from the area while working through this process.