We can charge Ni-Cd or Ni-MH simply by placing a series resistor to limit current from the power source to make efficient loading. But not so with lithium ion cell (Li-Ion) which has a capacity greater than ever and don’t need to be completely discharged to charge them, but require a strictly controlled charging.
Automatic battery charger circuit is possible to realize a battery charger with excellent quality that allows it to recharge the 12 volt car battery and dry battery used in the
alarm system. Operation is completely automatic, because it connects battery, battery charger will only charge the battery if it runs out, because it automatically disconnect the batteries fully charged. This device is supported by transformer with secondary voltage is 14-15 volts with a minimum of 3 Ampere current.
This is a car nicd battery charger circuit that can charge any Ni-Cd battery between 4.8 and 4.4 volts from a classic 12 Volts car battery. The charging current is constant it can be selected from the values of 50 to 120 mA by the selector S.
The solar battery charger circuit is nothing but a dual comparator that connects the solar panel to the battery when the voltage at the latter terminal is low and disconnected if exceeding a certain threshold. Since it is only by measuring the battery voltage, it is especially intended for lead batteries, a electrolyte liquid or gelled, that adapt the best of this way.