A very simple Ni-cd battery discharge limiter electronic project can be designed like in this circuit diagram using few common electronic parts .
As you can see in this electronic project , this circuit is very simple and can be used in many compact designs . This circuit disconnects the battery from the load when the output voltage falls bellow a preset level . C1 charges through R1 and turns on Q2 .
Collector current flows through R2 turning Q1 on and battery is connected to the load . When the output voltage falls bellow a point set by RV1 , Q2 turns off , Q1 turns off and further discharge of the battery is prevented .
The maximum output that can be supported by this discharger circuit is around 3 amperes . At the input you can connect on or two 12 volt Ni-Cd batteries .