This is a follow-up to my post on 6/11/10 that covered performing MPPT using a DC electronic load (eload). MPPT with an eload is done for design verification and durability testing of Photovoltaic (PV) devices like PV panels and concentrated PV. Besides just performing MPPT related testing, eloads make great solutions for I-V curve characterization for manufacturing and R&D test. They are great for testing high current PV devices like large area cells, modules, panels, and concentrated PV since eloads can sink and measure high current for a low cost. Below is a link to a video on youtube starring yours truly that covers using an eload for characterizing I-V curves.
Video link: Testing High Power Solar Cells and Modules Using Agilent's Electronic Load