Solar panels or photovoltaic panels?

What is a polycrystalline panel? It is one of the 3 kinds of photovoltaic panels on the market. It is called polycrystalline because there are several crystals in one cell, as a monocrystalline panel has one crystal only by cell. The quality / price ratio is better for a polycrystalline panel  than a monocrystalline panel because even if the performance difference is around 1 or 2 % better for the monocrystalline  (it used to be higher but the commercial success of the polycristalline type allowed the technology to improve quickly), whereas the price difference can be quite important with an advantage for a cheaper polycrystalline panel because less complex to build.  The third kind of panel is called amorphous. It has several advantages as a great performance in low light, and a conception of thin cells so also very light cells.  Nevertheless, the performance with important light is not as good as the two others.

Left to right: a monocrystalline cell, a polycrystalline cell (note the different crystals which form the cell) and an amorphous cell.

Some important things to know:

• the performance of a solar panel is changing with the temperature. In fact the technical characteristics are given for a temperature of 25°C. The solar panel performance decreases when the temperature goes below or above 25°C.
• the nominal power of the solar panel is calculated by convention at an angle of 90° between the solar rays and the panel. The change of this angle decreases the performance of the panel.the cells are connected between them in series. The maximum power of a cell is determined by the weakest cell. Note that a shadow above one cell will thus decrease the power of all the whole panel.A battery repartitor designed for your solar panels can really improve the charge of the on board batteries.

Space optimization with amorphous solar panels on the Lagoon 620 bimini top.