This is the circuit diagram of a very powerful and efficient Ni-MH battery charger using IC LT4060 from Linear Technologies. In addition to Ni-MH batteries Ni-Cd batteries can be also charged by slightly modifying the circuit.For charging Ni-Cd batteries connect the CHEM pin (pin12) of the IC to +Vcc.Here the circuit is configured to charge 2 cells connected in series. By altering the connections of SEL0 and SEL1 pins, upto 4 batteries in series can be charged using this circuit. For charging a single cell, connect SEL0 and SEL1 pins to GND. For charging two cells, connect SEL1 to GND and SEL0 to Vcc. For charging three cells, connect SEL1 to VCC and SEL0 to GND. For charging 4 cells, connect SEL0 and SEL1 pins to VCC. The circuit also features temperature based charge qualification.An NTC thermistor connected at the NTC pin (pin11) of the IC serves as the temperature sensor
- The circuit can be assembled on a Vero board.
- Mount the IC on a holder.
- Preset R2 must be set around 4K.
- Type no of Q1 is not very critical. Any 3 to 5A PNP transistor will do the purpose.
- LED D1 serves as a charge indicator.