Free circuit schematics - wiparat.com

The charger in this project is designed to charge two AA NiMH or NiCd cells of any capacity (as long as they are the same) at about 470mA. It will charge 700mAh NiCds in about 1.5 hours, 1500mAh NiMHs in about 3.5 hours, and 2500mAh NiMHs in about 5.5 hours. [...] Link

Another Reverse engineered circuit diagram of a mass produced solar LED light. This light also automatically turns on when there is no light falling upon the solar cell but this circuit waits untill it gets bit darker outside than the one above. Although battery charging is through a schottky diode, some charging efficiency is lost [...]