The initial voltage of the battery pack, open-circuit, before the discharge has begun, but after a 30-second heating phase at around 300 mA.
These voltages are characteristic of the different chemistries. The expected values for fresh cells are:
- Alkaline: 1.55-1.60 volts per cell;
- Carbon-zinc: 1.65 volts per cell;
- Lithium primary: 1.75 volts per cell;
- Rechargeable NiMH: can vary between 1.3-1.4 volts per cell, depending on state of charge and the storage time before testing;
- Lithium-ion, lithium-polymers: 4.1-4.2 volts per cell.