 The numbers in the table below are for a temperature around 20 °C (68 °F).For temperatures that deviate more than about 5 °C (10 °F), a correction should be applied of −5 mV/°C (−2.8 mV/°F) per cell or −0.03 V/°C (−17 mV/°F) for a 12 V (6-cell) battery (higher voltages at lower temperatures and vice versa).A bad battery will have short I-phase and Uo-phase, but there is a risk of gassing, further damaging the battery.