Yes, you can recover an old lead acid battery under certain conditions. Lead acid batteries can often be restored if they have not suffered extensive damage or been deeply discharged.
All lead-acid batteries use essentially the same principles. This means you can use the same methods to rejuvenate all lead acid batteries. Although if you have a maintenance-free or sealed lead acid battery, they will have hidden caps that will need to be removed before you can revive them.
Personally, I always make sure that anything connected to a lead acid battery is properly fused. The common rule of thumb is that a lead acid battery should not be discharged below 50% of capacity, or ideally not beyond 70% of capacity. This is because lead acid batteries age / wear out faster if you deep discharge them.
This means you can use the same methods to rejuvenate all lead acid batteries. Although if you have a maintenance-free or sealed lead acid battery, they will have hidden caps that will need to be removed before you can revive them. So to rejuvenate your battery, you need to remove the sulfation build up on the cell plates!
This includes items such as motorbikes, jet skis and other power sports vehicles. For these applications, Gel lead acid batteries are recommended, since the silicon gel electrolyte holds the paste in place. Just because a lead acid battery can no longer power a specific device, does not mean that there is no energy left in the battery.
What is a lead acid battery?
Lead acid batteries are a type of wet cell battery. Every cell contains two different lead plates in a fluid containing sulfuric acid, called an electrolyte. If the electrolyte level in your battery gets too low, the lead plates are exposed to air and sulfation can occur.
So many lead acid batteries are 'murdered' because they are left connected (accidentally) to a power 'drain'. No matter the size, lead acid batteries are relatively slow to charge. It may take around 8 - 12 hours to fully charge a battery from fully depleted. It's not possible to just dump a lot of current into them and charge them quickly.