Normal Charge (Constant Current Charge)
Charge the battery with the current value specified by manufacturer or with approximately 1/10 of battery's rating capacity. (See the table below.)
| Type | Charging current (A) | CCA (A) |
|---|---|---|
| 55D23R | 4.0 - 5.0 | 356 |
| 75D23R | 5.0 - 6.5 | 490 |
- The charge control feature and specifications for judgment of charge completion depend on the device. Follow the instruction manual of the charger used.
- Keep the electrolyte temperature at 45°C (113°F) or less while charging. Stop charging when the temperature exceeds this value.
- Constant current charging
This method makes it easy to charge to 100%, since the electrolyte is agitated by the gassing occurred at the end of charging. However, the time for charging is comparatively long because the current value is kept constant.
- Constant voltage charging
This method completes charging in a short period of time due to the large current. However, it is difficult to charge to 100% because no gassing occurred at the end of charging and the electrolyte is not agitated. Therefore, the combined use with the constant current charging is preferable.
- Quasi-constant voltage charging
This method is widely used for commercially available chargers. Compared to the constant voltage charging whose charging current at the beginning of charging becomes large, it reduces the charging current by lowering the voltage at the initial stage, resulting in battery load reduction. The time for charging is comparatively long. However, this type of chargers can be manufactured comparatively inexpensive due to the simple control circuit (or manual settings). After the initial stage of charging is completed, it gradually raises the charging voltage so that the charging current is within the specification, until the battery is fully charged.
- Constant voltage/current charging
In addition to the constant voltage charging, this method controls the upper limit of the current. The constant current charging is applied at the beginning of charging, and the constant voltage charging is applied at the end. This makes battery charge comparatively efficient in a short period of time. Charging by generators is similar to this method.
Judgment of charge completion
- Specific gravity of electrolyte should be held within the specific range of 1.250 - 1.290 for one hour or more.
- Voltage while charging should be held within the specified range of 15.0 - 16.8 V for one hour or more.
- Gas is actively generated in all cells.
- The amount of charge reaches 1.2 - 1.5 times of the amount of discharge.NOTE: The amount of discharge/charge can be calculated by the following formula.
Amount of charge (Ah) = Charging current value (A) x Time for charging