What is the issue?Solar panels perform well when they are free of shade, or even in partial shadow, and the sun is directly above. However finding a position on a sailing vessel that will be continually optimised for light capture is unlikely.
To make matters worse a sailing vessel is highly space constrained and large solar panels will easily encroach upon boat operations and crew comfort.
The best solution is to build a dedicated panel gantry so that the panels are clear of the deck and are in an area of relatively little shade. However this is an extensive piece of engineering, requiring some specialist work, investment and it will dramatically alter the vessels aesthetics.
Why address this?Power on a seagoing vessel is a scarce resource and every available source of power generation needs to be absolutely maximised. This is particularly the case with solar panels that are a highly expensive investment and return on investment is important. Yet the vessel must be liveable and the personal trade off’s need to be minimised.
How to address this?A simple solution is to remove the top guard rail in the cockpit area, where you have the dodgers, and replace it with a stainless steel tube. Upon this tube you can mount a panel supported by a board, or panels if you elect to go on either side, that may be rotated into place as required – see figure one.
Attaching the stainless steel tube can be accomplished very simply and needs no specialised equipment or modifications. Connect it directly on to the stern pulpit by sliding a clevis pin and split rings (should it need to be removed in an emergency) through the established lifeline eye. At the other end drill a hole through the stainless steel tube and fit over the head of the stanchion post, again securing it with clevis pin and split rings. Grind and sand off (with a fine grade wet and dry paper) all corners so there are no sharp edges on the tube.
Once this is in place attach the solar panel to an oversized board. Heat affects the panel’s performance so it should be slightly raised from the board using washers as spacers to allow for free ventilation underneath. A half dozen or so one inch ventilation holes beneath will help this cooling. Round the corners of the board and sand down all the edges as being in the cockpit people will, in time, fall up against the panel. Clamp the board to the rail with stainless steel U-bolts and use wing nuts to easily adjust the requisite tension required to twist and hold them in place. Take the power cable down through the deck via installing deck plugs. This will enable the panels to be easily unplugged and removed if you are leaving the vessel in uncertain waters.
Most people insert a diode to stop power floating back across the panel during the night. If you are wiring up more than one battery it is prudent to insert both diodes and fuses. Finally make certain there is plenty of water in the batteries before the solar panels get to work and monitor the charge carefully for a few weeks so you strike the balance between charge and consumption.
Using this simple system solar panels can be turned out of the way when need be and also flipped out to soak up the sun as required. They can also be tuned to some extent into the sun, by a helpful nudge from a passing member of the crew. Although tuning is only on one axis, which does not enable complete optimisation, it is still far better than completely fixed panels and can make a dramatic charging performance difference.
With thanks to:Michael Harpur, Yacht Obsession.
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