Solar Shading occurs when part of a solar panel or array is shadowed by an object or debris.
If the potential of shading is not managed correctly then the output of power harvested from a panel or array can be greatly reduced. This issue is particularly prevalent on sailboats, where on-deck space is limited often being shadowed by general rigging, masts and sheets etc.
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Modern Sail Boats And Their Reliance On Solar
Modern sailboats can often find themselves falling into the trap of being completely reliant on electrics. Just think about a typical setup; 230v inverter, 12v navigation system, communication, emergency bilge pumps and more relevantly electric propulsion.
Oh yeah, remember that thing that helps you escape a bad weather front or stops you from being pushed onto shore when the conditions are unavoidable! If a vessel doesn’t have an onboard generator or inboard engine then solar is a vessel's lifeline at sea. A trickle of power that may provide enough juice to keep a boat pushing a few knots against a tide in an emergency.
In this Video Gary Does Solar takes on some of the common myths surrounding solar shading. Fortunately for us, solar shading shouldn’t be a major issue providing it's accounted for in the build and setup.
TIPS AND COMMENTS
Our Setup
We are currently restoring an Atlantic Clipper 36 and repowering with an electric inboard motor. Our first installation of a 3-panel series array failed miserably. In fact the solar shading on this array was so bad that it dragged the voltage down to a point where our 48v Victron MMPT couldn't harvest any power from the UK winters limited sun.
We mitigated this issue buy separating the panels up into smaller arrays and connecting them in parallel. We then used a boost MMPT to take the voltage up to a suitable level for a 48v 16S lithium phosphate bank. There are many different ways to skin a cat but before you choose your system, have a good look over the options.
We're always try advise;