Jan 06, 2014 · Jan 5, 2014. #2. 12.2 volts is 50% depth of discharge on a battery. Going down below 12.2 volts reduces the life of the batteries. 12.0 volts is 75% discharged. So, if you are changing the low voltage cutoff to less than 12.2 volts, you are reacting to a symptom of weak, or undercharged batteries, or of batteries already nearing their life cycle.