Performance of amorphous silicon solar cell module and solar lantern

The solar lantern (manufactured by BHEL) could regularly be lit for 5–6 h up to a maximum of 7 h, if the battery was fully charged. It is desirable, for regular use, that the solar lantern should be lit for not more than 5 h a day if the clear sky condition exists. If the weather is partially cloudy, use of the lantern should be reduced accordingly. A performance study of the amorphous silicon (a-Si) module shows that the maximum power transfer voltage (V_mp) and corresponding current is ca. 65 and 75% of the open circuit voltage (V_oc) and short circuit current (I_sc), respectively. Efficiency of the module is 3–4% under field conditions and is slightly greater for a higher ambient temperature.