Here is an ideal solution to harvest Solar energy for charging purpose. This charger can replenish almost all types of batteries including Mobile phone battery. It uses a Solar Module to convert light energy into electrical energy
The circuit is self explanatory. A 12 volt 5 Watt solar panel is used as the source of current. The cells in the panel are made up of semiconductor material which transforms light energy into electrical energy. When the sunlight is maximum, the solar module can generate around 16.5 volts at 400 mA. This current is used to charge the battery. Diode D1 allows current into three regulator ICs to provide regulated voltage to the load. IC1 7812 gives 12 volts and 400 mA current to charge a Lead Acid battery.
The battery can be connected to point C and ground. IC2 7806 gives regulated 6 volts to charge NiCd battery. Resistor R3 restricts the charging current. IC3 7805 provides regulated 5 volts to charge all types of Mobile phone batteries which are rated at 3.6 volts. Resistor R2 restricts charging current to a safer level. Point A can also used to charge Lithium ion and NiMh batteries. High value capacitors C1 and C2 act as current buffers so that a short duration interruption in current flow from the panel will not affect the charging process. Red LED indicates the charging process.