Deep Discharge Protector for 3.6V Li-Ion Battery

A rechargeable battery’s load should be disconnected at the point of complete discharge, to avoid a further (deep) discharge that can shorten its life or destroy it. Because a battery’s terminal voltage recovers when you disconnect the load, you can’t simply disconnect the load when the terminal voltage dips below the established threshold and then re-connect it when the voltage returns above that threshold. Such action may produce chatter in the disconnect switch. The project shown here is a complete solution to this problem.