FAQ: The LP12V battery voltage levels

Question: I am discharging the 12V LP battery.  I was thinking that the battery will have 12V when full, 6V when in half-empty and 0V when empty. Is this so?

Answer: No. The battery does not work this way and the battery voltage does not change this linear way. The battery voltage does not change much with the discharge. For LiFePO4 cells the voltage (without load) stays always around 12V to 13V, so by reading the voltage of the battery, it is not possible to say what amount of the capacity is left in the battery. Also when under load the voltage does not change much. When discharging from full the battery will stay between 12V and 13V for the most of the time. Then the voltage will rather quickly drop bellow 12V.  We recommend stop discharge bellow 12 volts. When the voltage is bellow 12V, the battery is close to being empty and not much energy is left.

Overview of the LP12V batteries charge levels: 

• Full charge level – 14.6V (3.65V/per cell)
• Regular operating level (under load) – 12V to 13.4V
• Low voltage level (underload) – bellow 12V
• Minimal voltage level – 11V