Answer to Question 1.

1. What types of battery charger are available?

There are three types of charging system commonly used in industrial applications. Constant voltage, Constant current and Traction. All three employ sophisticated control circuitry dedicated to controlling the amount of current delivered into a battery.

Constant Voltage types are used to charge Wet Lead-Acid batteries found in automotive applications, Sealed Lead-Acid batteries used in most industrial applications around the world and nicad cells. The charger monitors the battery voltage and delivers a level of current sufficient to raise the battery voltage to the fully charged level of approx. 2.25 volts per cell (VPC). A higher boost potential is sometimes provided where the battery manufacturer recommends it.

Constant Current chargers are used to recharge Nickel-Cadmium batteries (Nicads) used in small portable appliances such as computers and mobile phones. The charger delivers a continuous amount of current into the cells regardless of the battery potential. Sometimes two levels of charge are utilised, starting at a maximum and switching to a lower level at the end of a particular event. The charging time is limited to prevent overcharge.

Traction battery chargers employ a combination of both of the above where the voltage of the batteries is measured and a constant amount of current is delivered until either the cells reach a pre-set level or a set period of time has elapsed. The charger output current and/or voltage is then slowly reduced as the cells become fully charged.

Modern battery manufacturers are able to supply details on the correct charging regime for the cells they produce. From here it is just a matter of selecting an appropriate charger.