Circuit Wiring Solution

Ni-cad charger with current and voltage limiting. Lamp LI will glow brightly and the LED will be out when the battery is low and being charged, but the LED will be bright and the light bulb dim when the battery is almost ready. Ll should be a light bulb rated for the current you want (usually the battery capacity divided by 10). Diode D1 should be at least 1 A, and Z1 is a 1W zener diode with a voltage determined by the full-charge battery voltage minus 1 V. After the battery is fully charged, the schema will float it at about battery capacity divided by 100 mA.