Charging and discharging of batteries

1. Discharge

The termination voltage at different discharge currents must not exceed the specified value. Charge the battery immediately after being fully or partially discharged. For optimum service life, the battery discharge depth is recommended not to exceed 60% of the rated capacity. Discharge of more than 60% is termed as deep discharge, which will shorten the battery life.

2. Floating charging and balanced charging

Floating charging operation is the best operating condition for the battery. At such time, the battery is always fully charged. Operating under this condition, the battery will reach its longest service life. At 25°C, the floating charge voltage of battery is recommended to be set to 2.23~2.27V/cell. This charging method requires about 24~36h to complete recharging. In order to optimize the performance of battery, the floating charging voltage should be adjusted according to the ambient temperature. The temperature compensation coefficient is -3.5mV/℃/cell battery. The floating charging voltage varies at different temperatures.

For optimum service life, the battery discharge depth is recommended not to exceed 60% of the rated capacity. Discharge of more than 60% is termed as deep discharge, which will shorten the battery life.

● Gel series battery pack need to be balance charged or recharged in the following cases:

①The battery pack should be recharged before the battery system is installed and put into operation;

② The battery is put out of use for more than six months;

③ The battery has been in floating charge state for extended period of time; the battery has not been discharged above 40% C20 capacity, and the battery should be regularly balanced charged. The balanced charging cycle is 6 months to 1 year.

● The recommended methods for balanced charging / recharging are as follows:

Balanced charging voltage 2.35V/cell (25 ℃), current limit 0.15C10 (A), charging time 8~12 hours (or performed at intervals).

The charging voltage should be adjusted according to the ambient temperature, and the temperature compensation coefficient is ± 3.5mV / ℃ / cell.

After balanced charging, for backward batteries whose floating charge voltage is still lower than 2.18V/cell, discharge 0.1C10 (A) for 4~6h, balanced charging with current limit of 0.15C10 (A), and 2.37V/cell constant-voltage .

3. Recharging

The battery should be recharged immediately after discharging. The recharging method is recommended as follows:

Charge the battery with constant current not higher than 0.2C10 (A) until the average voltage of the battery cells rises to 2.33~2.37V/cell, then use 2.33~2.37V/cell for constant voltage charging until the battery is sufficiently charged. The full charging sign can be judged by either of the following two methods:

● In the state of constant voltage, the charging current value during the last three hours of charging is basically unchanged.

● The charging voltage should be adjusted according to the ambient temperature, and the temperature compensation coefficient is ± 3.5mV/℃/cell.