How to recharge batteries that have lost some or all of their ability to charge.....this will work on led acid, nickle cadmium (NI cad) and nickel metal hydride (NiMH) batteries. The only thing your going to need is a zip lock bag and a working freezer.........Don't throw that battery out just yet, this could work for you!
A quickly and economically-built, custom rig that will charge and discharge each 7.2 stick on its own circuit at about 650 mA ... all 20 sticks simultaneously! You will need (20) 15 ohm, 13 watt resistors, (40) leaf spring battery contacts, a 4 gauge battery jumper cable, some dimensional lumber, a conventional lead-acid automotive battery with 2/10A charger. Final test of each cell with automotive battery carbon pile load tester.