Boat ElectricsFlexible Solar Panels

 

Flexible Solar Panels

by Kurt Küpper*

Some years ago flexible solar panels made by US company Unisolar were very popular in the boating community. These had eyelets that allowed them to be temporarily or permanently mounted or strung up without the expense of an often ugly stainless steel support structure. Apart from that practicality, the Unisolar panels were amorphous, and could thus tolerate a degree of shading. Unfortunately these have been unavailable for a good number of years.

Several other very thin and soft flexible panels did come onto the market, but did not prove to be very successful.

In recent years some very well designed and made thin bendable panels from Germany came onto the market. These are top quality panels that can be glued onto flat or curved decks and hatches. They can be walked on, being protected by Teflon coatings. The only problem with these is that they are exorbitantly expensive.

With great interest we heard of the introduction of a new type of flexible panel to the Australian market about a year ago. These panels were developed and are made in Italy by a company called Solbian.

They have developed a technopolymer (i.e. a plastic) for the lamination of crystalline cells. No glass is used.

This high strength polymer makes the PV module particularly resilient, flexible and thus adaptable to different surfaces and mounting locations. Their technical characteristics make them specially suitable for marine application. The panels have monocrystalline cells with an efficiency greater than 22.5%.

Their efficiency is comparable to that of traditional panel made in glass, but their weight is about 1/8. The output of these panels will be affected by shading. It is therefore not a bad idea to rather fit more but smaller panels, so that partial shading only reduces the output of the panels in the shaded area.

The panels can be rolled on a fairly large diameter, but the big advantage of their flexibility is that it allows the panels to adapt to the mounting surface. Their overall thickness is just 1.5mm.

The panels can be mounted by one of three methods:

Just like the Unisolar panels, it is possible to have them supplied with holes punched along the edges, with stainless steel eyelets. They can thus be temporarily tied down or secured with rubber straps (octopus straps). The panels are available in long narrow formats, ideal to secure onto a yacht boom.

Flexible Solar PanelThe second option is to glue them down permanently onto a deck, coach house or hatch cover. In this instance a very high bond adhesive is applied to the panel before it is supplied. The panels can be walked on, provided of course that this is reasonable traffic, i.e. deck shoes or bare feet are OK, but don’t mount it right in front of the cockpit entrance which gets the most traffic or walk on it with heavy footwear.

Flexible Solar PanelLastly an innovative new option is securing the panels by means of a zip fastener. One edge of the zip is sewn onto the polymer base. The other half can be sewn onto another panel if two panels are required to be joined next to another, or onto a bimini cover or boat cover, etc.

The panels are supplied with junction boxes and fly leads with MC4 solar connectors. Alternatively, the panels can be supplied with solder straps on their underside. The electrical connection can thus be made straight down through the mounting surface, with no junction boxes or cables on top of the panels.

The best news is that these panels are well priced. They cost from about $500 for a 40W panel to about $950 for a 125W panel. At a slight premium extra high efficiency cells can be specified, to maximise the output of the system where little space is available. This may still at first sight appear costly, but once the saving achieved by not having to have a stainless steel support structure made and fitted is taken into account, these panels are very economical.

 

*Kurt Küpper is director of Aquavolt Electric Boat Parts. Tel: 02 9417 8455 www.aquavolt.com.au