Solar Ni-Cd Cell Charger
This simple, portable solar battery charger provides a convenient method to charge rechargeable Ni-Cd batteries while learning about solar cells. This silicon solar cells are connected together in series,
and each battery is protected with a blocking diode so that electricity flows only from the cells to the battery. Asimple and safe experiment would be to measure the battery voltage at various intervals during charging under a lamp or in the sun.