A: Open circuit voltage

When the battery is not charged and discharged and there is no load, the potential difference between the two poles of the battery is called the open circuit voltage.

The open circuit voltage of the battery will vary according to the materials of the positive and negative electrodes of the battery and the electrolyte. If the materials of the positive and negative electrodes of the battery are identical, the open circuit voltage of the battery will be the same no matter how large the battery volume and how the geometry changes.


B: Discharge current

Battery in connection with electrical appliances or load, the current generated is called discharge current. The unit is ampere (AMP), referred to as A.

C: Internal resistance of battery

The resistance of current flowing through the battery is called internal resistance, which includes ohmic resistance and polarization resistance.

The internal resistance of the battery is very small, which is usually expressed in the unit of micro ohm or milliohm mΩ.

In the general measurement situation, it is required that the measurement accuracy error of battery internal resistance must be controlled within plus or minus 5%, so special instruments must be used for measurement. Different types of batteries have different internal resistance. For the same type of battery, the internal resistance is different due to the different internal chemical characteristics. Internal resistance is an important technical index to measure battery performance.

Under normal conditions, the battery with small internal resistance has strong high current discharge ability, while the battery with large internal resistance has weak discharge capacity.

D: Discharge termination voltage

When the battery is discharged, the voltage drops to the lowest working voltage when the battery is not suitable for further discharge. According to different battery types and different discharge conditions, the requirements of battery capacity and life are also different, so the specified battery discharge termination voltage is not the same.

Requirements for discharge termination voltages:


Cell means the single cell of battery, and the cell voltage is approximately 2V (2.13-2.18v);

There are six cells in the 12V battery, and the termination voltage is 6 times of that of the single cell;

There are three cells in 6V battery, and the termination voltage is three times of that of single cell;

Other analogies, follow the above laws.

After the battery is discharged, the battery should be fully charged within 24 hours to avoid affecting the battery capacity.

Note: Capacity is not a fixed value and varies with discharge conditions like ambient temperature and battery used time.