Charging and endpoint detection of NiMH batteries using solar energy

This paper introduces the design and implementation of solar powered battery charger for NiMH batteries. The charger consists of battery unit having 10 NiMH cells of capacity 2100 mAh. The cells are connected in series to form 12V battery pack, on which temperature sensor is mounted. This charger employs a very simple algorithm based on parameters such as temperature, voltage and charging current. The charger periodically measures battery parameters. The design is implemented with 8 bit RISC microcontroller. The charger performs well at different charging rates. The experimental result shows the performance of the proposed solar based charging system.