Verifying an economic viable load for experimental purposes relating to small scale PV modules

Abstract

Optimizing the output power of any PV module requires a number of factors to be considered, including the tilt angle, orientation angle, environmental conditions and the energy management system. This system often includes a maximum power point tracker that is required to adjust a module’s output voltage to a value which enables the maximum energy to be transferred to a given load. A solar controller may also be used in the energy management system to prevent batteries from overcharging, to prevent back flow of current from the batteries to the solar modules and to provide maximum reliability and service life of the whole system. However, when various parameters of PV modules need to be investigated in real life applications, what type of economic viable load is suitable for experimental purposes relating to small scale PV modules? The purpose of this paper is to present empirical evidence contrasting the performance of three identical 10 W polycrystalline modules connected to three unique separate loads. A LabView software program was developed to record and display the voltage and current measurements from the PV modules using a data logging interface circuit and an Arduino board. Results indicate that a solar controller extracts more power from a PV module (on average 3.9% more power), as compared to a regulated LED and a fixed load resistor. However, the regulated LED follows a profile similar to that of the solar controller, drawing on average 2 W less per day than the solar controller. On the other hand, the fixed load resistor draws on average 8 W less per day than the solar controller, following a profile different to that of the solar controller and regulated LED. The regulated LED is therefore verified as an economic viable load for experimental purposes involving small scale PV modules.