Charging a battery pack from a solar panel?
A part of my culminating project to graduate from my technical school involves a simple circuit. I want to have a solar panel charge a 7.2v battery pack. This will then output to a female USB port for charging mobile devices. I have majority of my circuit figured out. However, I am not sure how I can effectively regulate the charging of the battery. I know I need a solar panel that outputs higher voltage than the battery, and a Diode in between to prevent backflow into the panels. However, How would I prevent overcharging?