Solar technology is very popular now a days and it is growing day by day. Solar gadgets are also taking attention of people and uses of solar energy is taking place not only around us but it is also used in space stations where no electric power is available. The schematic shown here
is a very effecient automatic solar battery charger circuit which can be used to charge 12V SLA batteries from solar cells. The circuit is using an LM317T voltage regulator IC. The BC548 transistor is working as a switch which will disconnect the ground of the LM317T from the solar cell when the battery become full charge.