A solar panel should be designed to last at least 25 years, so build quality is an important factor in choosing a quality solar power (photovoltaic) system.
To make a solar panel, solar cells are laid between a superstrate layer (usually glass) on the top and a backing sheet (usually plastic laminate)on the bottom. This is then placed inside an anodised aluminium frame. The junction box is glued to the backing sheet. Electrical cabling joins the junction box and the inverter.
What to Look For
Silicon
Silicon is the main element in the solar cells used to create electricity. Not all silicon is of the same grade. Cheaper panels are more likely to be constructed from a lower grade of silicon. Unfortunately the customer has no way of knowing the grade of silicon used. Low grade silicon can lead to early cell failure and loss of output in your system. Generally more expensive solar modules are more likely to be made using A-grade silicon.
Laminate
- Solar cells are glued to a backing plate usually made of plastic laminate. In inferior panels the laminate, can lift. If this happens the panels can become dangerous as the electrical current is not insulated.
- Making a quality laminate is the most important process to guaranteeing at least 25 years performance.
Frame
- Anodised aluminium (aluminium oxide) is the second hardest substance known to man. So the thicker the frame the better as it can cope with more load and thus more storm stresses. At least 45mm is considered good.
- A frame with twin-wall design is better because it has higher load capacity (Look for the load on the specifications, measured in Pa).
- The section of the frame overlapping the glass should be as wide as possible. This ensures that the bond between the frame and the glass is strong.
- A self locking frame construction will be more durable than one which requires the frame to be screwed together.
Inverter
If the inverter is be located outside, ensure that it is rated for outdoor usage.
