Abstract – This paper proposes an energy efficient charge
controller scheme for solar power based standalone lighting
systems. This concept is being given keeping in mind the
necessity, cost and importance of lighting in remote areas. The
proposed scheme comprises of efficient charging and discharging
of battery with a very well known technique, Pulse Width
Modulation (PWM). The scheme assumes d.c. operated WLED
lamp as its output light source due to its high luminosity and
unprecedented characteristics. Thus, the whole system operates on
d.c. right away from solar panel output to battery to output light
source. By varying the duty cycle of the d.c. current with PWM
technique the battery can be efficiently charged and discharged
through a common microcontroller circuitry thus bringing down
the cost. The battery terminal voltage acts as the feedback for
generation of PWM by microcontroller. As a result, light is
available for longer hours, the battery works for longer life and the
overall cost of the system may come out to be very low with a
very bright clear WLED lighting, an ideal combination for energy
efficient solar power based standalone systems for lighting.