Hi, I have a cheap mp3 player in my car that runs off a 1.5v aaa battery. I have to change the battery once twice a week as I forget to turn the thing off as it is plugged into the tape slot. My plan is build a circuit that will trickle charge a Ni-MH battery via a solar cell and power the mp3 player during daylight, and the battery will power it in bad light/ darkness.
This is a very cheap mp3 player and the only power connection it will take is off the battery terminals.
I have a 2.5v solar cell on the way from e-bay, and I know I need a diode to stop the batterry discharging via the solar cell, and possible a voltage regulator so as not to overload the mp3 player.
Any other suggestions to improve on this?