How can I use solar cells to recharge AA batteries?

Question

I am doing a project for my EE100 class. What I want to do is build a kit car and instead of using AA batteries would it be possible to use solar cells. I have two cells one at 1V and the other one at 2V. wich in series is 3V. That is the equivelent to 2 AA batteries. Or could I use rechargeable batteries and have the solar cells charge them without ever having to remove them from the car. I intend to mount the solar cells on the kit car and wire them into the battery holder. is this even possible?

Answer 1

You may be able to power the car with your solar cells. In addition to the voltage, you also need to consider the current requirements to drive the motor. While the solar cells may be capable of producing enough voltage to drive the motor, they may not be able to produce enough current at that voltage.

If you want to charge batteries from your solar cells this may also be possible, depending on the type of battery you want to use. With smaller solar cells you will probably need to use 'trickle' charging, since this method uses less current over a longer time. You can see what charging methods will work with which type of batteries by checking the manufacturers data sheets. Have a look at this site to get an ideas for the different types of batteries and the methods used to charge them.
http://www.panasonic.com/industrial/battery/oem/

Answer 2

I hope the output current at the charging voltage will be enough to charge the batteries, without taking forever to do it. If you can't charge at the rate of several milliamps, it might not be worthwhile.

Maybe you will need two or more cells to get sufficient current.