MAX712 charger circuit for gel cells NiMH NiCd batteries
Using the MAX712 can be designed a charger for Nickel Metal Hydride (NiMH) and Nickel Cadmium (NiCd) batteries .
This charger based on MAX712 chip require few external components and is easy to build .
For the MAX712 charger is needed a power supply with a output voltage with at least 1.5V higher than the maximum battery voltage. Charge completion is determinate by a voltage-slope detecting analog-to-digital converter , timer, and temperature window comparator .
The MAX712 terminates fast charge by detecting zero voltage slope, while the MAX713 uses a negative voltage-slope detection scheme .
The MAX712 are powered by the DC source via an on-board +5V shunt regulator.
This charger can be used even for gel cells batteries . This circuit charger can be used for charging 12 volts gel cells batteries .
The value of the Rsense is around 0.62 ohms and 1 watt resistor and the power transistor used can be TIP42 , 2N6109 or other similar type .