What is a Shade Tolerant Solar Panel?

Most of us have shading on our boats from rigging, equipment poles or other boat structures.  Reduction in performance due to shading is a significant issue for solar panels.  We at Custom Marine Products have developed a new panel design that significantly reduces the impact of shading and clouds on solar panel performance.

First, a bit of background on how typical solar panels are designed.  Solar cells are wired in series to get the panel voltage up to a level that is appropriate for its application.  These series strings usually go down and up the length of the panel.  A solar panel may have one to 5 series strings. Higher quality solar panels have the cell strings isolated with diodes so a shaded string does not reduce the performance of unshaded strings. If there is shading across the panel, each shaded series string is significantly reduced in power output.

Our new CMPower shade tolerant solar panel is designed with multiple shorter strings of half-cut solar cells.  These flexible panels have four strings (four quadrants) all isolated with diodes.  The result is a panel that will perform well with boom shading across the panel.  In fact, our testing indicates that these panels have double the output of a standard panel in shaded conditions.  These panels are currently available in 115 watt and 145 watt sizes.  The junction box and wires are in the center of the panel rather than at an outside edge.  This may be problematic for some installations.
​See diagrams below for clarification.