I'm working on a project to build a (mainly) solar-powered boat. The boat will also have a battery for storing energy, and (naturally) a motor for propulsion. Additionally it will contain some electronics for turning the motor on/off, turning the rudder and so on.
What I've found challenging is to design the circuitry to connect the solar cells, battery and the loads (i.e. motor, electronics). The solar cells will have a peak power of about 30W-40W. They will probably give a voltage of about 8-9V, and currents up to ~5A (or 4-5V, ~10A). The battery voltage is not yet decided, but it may be 6V (or 12V if 6V gives too high currents). It will probably be a Li-Ion battery.
My question is: What kind of circuit will I need to charge the Li-ion battery with my solar cells? It would be an advantage if it is as simple/cheap as possible, but still treating my batteries properly.
Thanks in advance.