Problem Description:
SunPower PV solar cells have unique characteristics that cause them to conduct current in reverse more easily than regular rigid solar cells. In parallel connected PV systems if all or part of a SunPower PV panel is shaded, then other unshaded parallel panels can force current through the shaded panel and cause unnecessary heating that can cause discoloration of some rooftop materials and wasted power that can reduce system performance.
Solution:
Reverse blocking diodes placed on the positive output of every parallel SunPower PV panel prevents unnecessary heating and improves system performance. The diagram below shows where the diodes are installed. These diodes are low cost and easy to install by simply plugging them into the existing MC4 connectors.
Go Power! now provides reverse blocking diodes in every solar kit that includes solar panels with SunPower cells and we recommend that they are installed on every solar panel. This also applies to single solar panel systems so that if an additional solar panel is added in parallel by way of an aftermarket installation, then there will be enough diodes to effectively prevent solar panels from sourcing power into other solar panels. The reverse blocking diode Go Power! will be providing is shown in the image below.
Note that reverse blocking diodes are only required for solar panels made with SunPower cells. They are not required for other panels, but can help improve system performance.