3V solar ni-cd charger

Thread Starter


Joined Nov 20, 2015
I am a newbie in electronics and I want to build a simple circuit. Is it possible to wire a few 3V solar cells from pocket calculators to charge 2 or 4 ni-cd AA batteries?

If each battery is 1.2-5v and the cell puts out 3 how can I divide voltage to each leg/ terminal. And what of current? If I wire several cells together how do I wire it to multiply current?


Joined Nov 30, 2010
Each ni-cad cell is good for about 1.2 volts. batteryuniversity is a website with loads of information. It will save me several pages of typing today. :D


You connect them in series (plus to minus) to get higher voltage, you connect them in parallel (plus to plus and minus to minus) to get more current. They don't multiply, they add.

In general, the process of charging a cell from a solar panel is to connect them in parallel with a diode in one line to keep the battery from discharging through the solar panel. The battery uses up the current from the solar panel so much that the solar panel voltage sags down to the battery voltage, then they both rise together. The trick is knowing when to stop.

Go read about it for a while and come back with more questions.