POWER OUTPUT LOSSES IN SOLAR CELLS WHEN CHARACTERISED BY OPTIMAL RESISTIVE LOAD METHOD

摘要

The current and voltage of a solar cell canbe measured by optimal load method. However, thismethod does not automatically adjust the load toensure maximum power output as solar irradiancevaries, hence power output losses. This studyinvestigated the losses in power output that occur insolar cell when characterised by optimal load method.This was done by exposing the solar cell at differentillumination intensities (between 300 and 1,000 W/m2in the interval of 100 W/m2) and measuring currentand voltage using Keithley Source-meter as well asoptimal load (102 m ) method. From current andvoltage, maximum power output of the solar cell forboth methods were calculated and compared. It wasfound that the power output calculated from optimalload method (102 m ) were in good agreement withthose from Keithley 2340 Source-meter only between500 to 700 W/m2. As a result, the solar cell lostbetween 1.3 to 33.4% of its maximum power whenillumination intensities were outside the operatingrange of the optimal resistive load. Conversely, when aresistive load of 45 m (which is not optimal) wasused, the solar cell lost between 0.8 to 81.4% of itsmaximum power at various illumination intensities.