WA chargers
Wa chargers are characterised by the charging current of the charger being reciprocally proportional to the counter voltage of the battery. The charger delivers high current at low battery voltages and low current at high battery voltages. To be precise, the charger delivers the rated current at 2.1 V/cell, 50% of rated current at 2.4 V/cell and finally 25% at 2.6 V/cell. Wa chargers are not regulated. The Wa curve is created by correctly dimensioning the transformer and the choke coil. The charging process is affected by variations in mains voltage. In order to compensate for major deviations in mains voltage, the chargers can be switched between low and normal mains voltage.
Micropower’s product range does not include the simplest type of Wa charger with a fixed top charging time, but the STC is equipped with electronic control with variable top charging times that are automatically adapted to the charging depth of the battery.