Solar-Powered MP3 Player

Battery less way Inefficient way : Connect 1.5 V zener diode (its connected kinda reverse with the line to +) or 2x standard silicon diodes in series (normal with line to +) in parallel with the cell. Measure the volt before connecting the MP 3. This may load the cells to an extent where not enough power is left to the MP 3. Efficient way : PWM with a 555 timer or the like and large filtering capacitor at the end - search on the net for a circuit. If I have free time I can try to design one but I dont promise Battery way (recommended) Connect the cell in series with diode (low volt drop diode preferred) and them both in parallel with a charged battery to the player. The battery should balance the cell voltage and in addition charge off it Once in while measure the volts on battery Battery keeps 1.5 (or 1.2) volt - yay its working ! Battery rises above 1.6 - 1.7 volt - add another diode in series with the cell Battery is emptied slower - The cell not powerfull enough or put in too less light but tries its best to power ya MP 3. If you can make sure the cell is allways in bright light when connected try to remove the diode (allowing the battery to discharge on the cell may damage the cell - happens when cell volt < battery volt) Battery is emptied faster than without cell - Is the cell connected in the right polarity ?