Originally Posted by
jclevoy
In reading the owner's manual that came with my SPP2150 (the larger of the 2 batteries): This info is straight out of the manual.
12.85 Volts = 100% charge
12.5 Volts = 75% charge
12.2 Volts = 50% charge
11.9 Volts = 25% charge
11.6 Volts = 0%
John told me that it has been his experience that if you discharge one of these Stingers below the 25% level, then chances are that you have just ruined your battery. After this deep discharge, it will not hold a charge again. I don't plan to discharge mine below 12 Volts, and I plan to put them on the stinger chargers after each trip to the lake. They are on the charger right now.