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How to desulfate an old lawn mower battery

Desulfate A Lawn Mower Battery

 

This page shows how it is possible to desulfate a very badly sulfated old lawn mower battery. An old battery was purchased from a lawn mower dealership for scrap price for this project.

The battery pictured at the right shows the low voltage of the battery before the desulfation process was begun. The volt meter shows 10.76 volts. It is actually amazing that the battery showed even that much voltage because it was later discovered to be almost bone dry inside. Any battery expert will tell you that any voltage below 11 volts is harmful to a battery. This particular battery was no longer taking a charge with conventional battery chargers.

Low voltage of a badly sulfated lawn mower battery

 

 

 

First, clean the battery. Use water and a soft brush. You can use baking soda to render any leaking battery acid harmless.

Examine the battery for any visible signs of damage. Bulging case sides, burns or holes on the top of the case are signs that a battery had been damaged beyond recovery. Look inside the battery after the lid is off. If possible, check if the plates are badly corroded or broken up. Plates that have been physically damaged are signs of a bad battery. If the battery is outwardly undamaged, then chances are that you can desulfate it using the radiant energy charger and bring it back into a usable condition again. In many cases, the battery can be brought up to new condition.

The conditions of the lead plates inside your battery affect how well you can restore it. If the plats are not damaged, then most likely you will have a very good battery on your hands, as was the case with this old lawn mower battery. It was just badly sulfated, but the plates were still quite good inside.

Refer to the pictures below for the next steps. Use a screwdriver to carefully pry the lid off the battery. This will expose the battery cells. Notice in the last two photos, the white sulfation on the battery plates. This is a very badly sulfated battery. Also notice that no water is visible in the cells. The water level should cover the top of the battery plates.

Use a screwdriver to pry off the battery lid
Use a screwdriver to pry off the battery lid

 

Cover has been removed from the battery
Cover has been removed from the battery

 

 

The cells of the battery are dry
The cells of the battery are dry

 

White sulfation visible on top of battery plates
White sulfation visible on top of battery plates

 

Top off the cells with distilled water. Only use distilled water, not tapwater. Fill each cell to just above the plates. Put the cover back on the battery. Now your dead lawn mower battery is ready to be desulfated using the radiant energy charger. See DIY Radiant Charger for details.

Below you can see the newly desulfated lawn mower battery installed in a garden tractor. This is an 18 hp twin cylinder briggs and stratton engine being started by the restored battery. The volt meter reads 12.43 volts.

 

The battery is now working happily in this garden tractor
The battery is now working happily in this garden tractor

 

Desulfated lawn mower battery in riding mower
Desulfated lawn mower battery in riding mower

 

Restored lead acid lawn mower battery
Restored lead acid lawn mower battery

 

The first video below is of the sulfated lawn mower battery being desulfated on a homemade Bedini Simplified School Girl motor. This is restoring the battery using radiant energy.



The second video below is of the desulfated lawn mower battery starting the mower. The battery is fully restored to like new condition. It starts the mower every time without fail.

Restore a sulfated lawn mower battery to new condition with a Bedini SSG

 

Restored a sulfated lawn mower battery to like new condition

 

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Feel free to ask any questions or get help with your project on our Support Forum.



Final Notes:

Be very careful when working with batteries. Never work on a lead acid battery indoors. Always work in a well ventilated area. Batteries release explosive gasses when being charged.

Be careful working around battery acid. It is very corrosive and will burn skin, clothes and tools. Be sure to wash hands and tools thoroughly after working with lead acid batteries.



Disclaimer: The ideas presented here are for informational purposes only. Experiment at your own risk. We assume no responsibility whatsoever.





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Troy Reid

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