Note: “C
₁₀
” expresses the 10-hour-rate capacity value.
Table 4: Maximum Current (A)
Charge
0.2C
10
Discharge
0.4C
10
SOC
0.1CA
[%]
Fig. 5 The relationship between SOC and discharge current
(
Recommended operation range)
5.3 Charge
(1)Equalizing charge
Partially charged batteries should be given an equalizing charge at least once a week. Use the following equalizing
charge method.
Multi-stage charge: Apply currents of 0.2C
10
A to the first stage, 0.1C
10
A to the second stage, 0.05C10A to the
third stage and 0.02C
10
A to the fourth stage in this order. (switching voltage: 2.40 V/cell) After the terminal
voltage reaches 2.45 V/cell at the fourth stage, charge the batteries for about 3 hours.
Constant current/voltage charge: Apply a constant voltage of 2.45 V/cell (initial current of 0.1C
10
A or lower).
After the voltage reaches, charge the batteries for about 5 hours.
(2) Recovery charge
Conduct recovery charges in accordance with the equalizing charge.
Caution
: When the charge voltage deviates from the manufacturer-stipulated values, the following types of
adverse effects will occur.
Remaining high for sustained periods (overcharge): Promotes electrolyte leakage and positive electrode grid
corrosion, and shortens service life.
Remaining low for sustained periods (undercharge): Charge will become
inadequate, promoting positive electrode grid corrosion and degradation of negative electrode active materials,
and shortening service life. It will also become impossible to satisfy load, causing voltage disparity between cells.
When there are numerous instances of the temperature where a storage battery is installed exceeding the sphere
of 5~35
℃
, it is recommended that corrections be made in the charge voltage setting value, using
– 3.5mV/
℃
cell
temperature adjustment value with 25
℃
as the starting point.
5.4 Cleaning
Clean and dry conditions should always be maintained for storage batteries and the surrounding area.