One interesting observation is that you van reverse the use of this charger by using it as a geared motor. It has a good gear setup inside it, so if we connect 3.7-5 volts DC direct to the motor we can get a good movement by the crank lever to open a chicken feed door, or can entry ...etc.
Another worthwhile note is when you have any rechargeable item that broke or dies, do not throw simply. Shavers include a motor and battery to take. also chargers, cordless drills, Bluetooth sets, old cellphone...the harvest is worthwhile.