Update: Before you continue reading, please let me discourage you to use polycarbonate, (as I explain at the end of the post): You will be loosing money for the only reason that the cells and the polycarbonate doesn't have same expansion coefficient and lets the water go through it (very slowly), and all the efforts to avoid this disadvantages will fail miserably.
In this post we will see how to build a photoelectric panel DIY the most economical way, yet it is safe and durable (has to endure 25 years). As we shall see, the difficulty of manufacturing is very high, so I recommend it only for the handyman ;). In addition the process is long, but very satisfying if you like the "do it yourself" and are fascinated photovoltaic panels.
I have seen many examples in Internet short - lived home panels , some prepared with wooden frame , I doubt that last more than ten years, or in sealed with silicone tight box (so that moisture comes but then condenses inside unable to leave quickly, corroding cells), whereby the potential savings to the panel in a home goes for the short duration of efficiently it.As discussed in the previous post , my intention was to use polycarbonate, three times it economical than glass, plus much safer and lightweight whose only problem is that dilates 3 times more than glass, and has a light output somewhat lower than the glass (and falling further to whiten with the sun), but stays within a reasonable range during the first 30 years, which is what interests us.
To fasten the solar cells, I have sought more easily and economically; unused support or back cover, but linking them directly to the polycarbonate, and thus kill several birds with one stone :
- Reduces material costs,
- Quicken the panel,
- Avoid possible accumulation of moisture and / or water, as the polycarbonate is not totally impermeable (no plastic is, unless a barrier metal), so it is desirable that no gaps where moist air can accumulate.
- It allows some light to pass between the cells, so that the bottom remains partially illuminated.
- Cells give one the more "fresh" are higher performance; per ° C above 25, panel lose 0.5% efficiency. If we let the rear "air" only with a protective coating (paint, epoxy or silicone), will be best refrigerarán, last longer and give more electricity.