Free circuit schematics - wiparat.com

The MAX712 and MAX713 are nickel cadmium (Ni-Cd) battery fast charge controllers which will fast charge batteries from a DC source at least 1V higher than the maximum battery voltage. 1 to 16 series cells can be charged at rates up to 4C. A voltage-slope detecting analogue-to-digital converter, timer, and temperature window comparator determine charge [...]

This battery charger charges a NIMH 5-pack battery used in the BiPed robot in less than 1 hour, and charges the 10-pack NiCd used in the Snuf robot in about 30 minutes. To prevent overheating of the battery, the charging current is turned off when the slope of the battery-voltage turns from positive into negative. [...]