The following diagram is the schematic diagram of 12V NiCAD battery charger with charging rate of 200mA/Hour.
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 pot for 15.5V across the resistor.
Article from: http://www.hqew.net/circuit-diagram/200mA$2fHour-%E2%80%93-12V-NiCAD-Battery-Charger-circuit-diagram_3937.html