This is an economic circuit of a mini solar lighting system, solar panel 6V/2W is used to charge a rechargeable 4V/800mAh through a current limiting circuit load that uses a LM317T adjustable regulator 3 pin (IC1). Assuming a sunny day 6 hours, a panel will enviarr 2 watts for approximately 900mAh battery. The current can be reduced by increasing the value of R1, for example, 8.2 to 10 ohms ohms.