It seems to be pretty much standard procedure to throw out an old battery that has gone dead. It's also rather an expensive procedure because it usually entails buying a brand new battery that is usually very expensive.
But, it's a procedure that makes sense to most people because they don't realize that a battery that seems to be dead, an, if subjected to the right reconditioning process, start working again.
There are two types of lead-acid batteries.
In one, the cells have caps and are actually accessible when those caps are unscrewed, and in the other the cells are sealed. Both these batteries are actually capable of being reconditioned, if you know how.
When either of these battery types fails, it is possible to recondition them if you follow the following procedure exactly.
The first thing to do is to check the voltage of the battery, and for this you need a multi-meter.
Connect a multi-meter to the battery, and see what reading you get. If the reading of the battery is below twelve volts but still not below 11.7 volts, there's a good chance that you can recondition the battery and bring it back into working order.
How to go about it…
The first thing you need to do is to take about a liter of distilled water and begin to heat it. Please note that the water must be distilled water, as ordinary water contains many dissolved minerals that will disrupt the chemical processes inside the battery. So distilled water it is. Bring it to just little below the boiling point of water.
At this point, you need to add in some magnesium sulfate - about a quarter of a kilogram should be quite adequate. You need to make sure that the magnesium sulfate dissolves completely, and to ensure this you need to keep stirring the liquid until it does.
The next step actually depends upon what sort of battery you have, that is to say, whether each cell of the battery is sealed, or whether there are caps that screw off that allow you to access the cells of the battery.
If the cells of the battery have caps that you can unscrew, then all you need to do is, of course, to unscrew the caps and open the cells of the battery. However, if it is a sealed battery, you will need to drill through the cap of each cell, very carefully.
You need to be very careful that your drill doesn't penetrate the plates themselves, or damage any of the terminals inside the cell. Drill with a great deal of control.
After this, the procedure is exactly the same for both types of battery.
You empty out the cells of the batteries and you replace the liquid inside with the liquid that you have prepared. You can use a funnel to ensure that none of the heated magnesium sulfate mixture spills as you pour it into each cell.
Now, you need to use a trickle charge to charge the battery.
It might actually have to be left charging for anything between twelve to twenty hours before it is fully charged. At this point, discharge it completely and charge it all over again. That's it, your battery should be operational.
I might point out that the main expense in this procedure is the charger itself. If you're trying it for the first time, I would advise you to borrow a charger from someone who has it, rather than buying it the first time around.