Do a search on the internet....plenty of sites.....
But....be aware that if your lucky and it's only one battery with a minor issue, then it might work....otherwise, you are better off buying a new battery.
For future reference, you can get the max life out of a battery (not car battery) by using it until it dies....fully charge it...but don't let it sit on the charger....unless it's a really good charger....most just cook the battery, thus reducing it's life.
BTW....Welcome...