The following diagram is the schematic diagram of 12V NiCAD battery charger with charging rate of 200mA/Hour.
Resistor: 1 K Ohm, 68 Ohm, 2 K Ohm, Potensiometer 10K Ohm
Diode: IN4001, 2x Zener IN752
Transistor: 2N2219, 2N2222
This NiCAD battery charger circuit charges the battery at 75 mA until the battery is charged, then it reduces the current to a trickle rate. It will fully recharge a dead/unpowered battery in 4 hours and the battery can be left in the charger indefinitely. To set the shut off point, connect a 270 ohm / 2 Watt resistor across the charge terminals and adjust the potensiometer for 15.5V across the resistor.
The input voltage for this battery charger circuit is 24VDC, you may use a general purpose power supply or 24V lead acid battery from your car.