Product Warranty and Power Output Warranty
Author: Solar 4 RVs
Power output warranty
A power output warranty typically guarantees a solar panel to meet at least 80% of its original power output after 25 years of service and retains at least 95% of its original power output after 1 year of service.
Many solar panels have a 25-year output warranty, although by saying it is a 25-year warranty it can easily be misinterpreted as a product warranty even though it is a power output warranty.
Panels can fail because of defects in the parts of processes used during manufacture (covered by the product warranty), or they can fail because of handling, installation or operation after manufacture (usually not covered by the product warranty).
Under Australian consumer law, importers are responsible for manufacturers’ warranties.
Why do panels fail?
1. Defects in component parts (covered by the product warranty):
a defect in a cell such as chips, cracks and burnt areas
defective top sheet, bottom sheet or lamination
2. Manufacturing processes (covered by the product warranty):
lamination not carried out at correct temperature
cell spacing is not appropriate and cells may overlap
vacuum seal not created during manufacturer
scratches on the surface from tools and drums
poor soldered connections between cells and into junction box
junction box not sealed properly
3. Stressors during handling, installation, operation (usually not covered by the product warranty):
- Mechanical stressing, e.g. over flexing or repetitive flexing (flexible panels are ideally suited to be flexed once and adhered to a surface as opposed to a solar blanket that can be folded repeatedly)
- Thermal-mechanical stressing between panel and substrate
Examples when a damaged panel will not be covered by the product warranty:
- Installation has not been carried out according to the instructions, e.g. the panel is installed on canvas over a support beam causing excessive flexing to the panel. See our installation instructions for examples of this.
- The mounting structure has a high coefficient of thermal expansion and an inappropriate adhesive has been used to adhere the panel to the surface that has not allowed for thermal expansion and caused the cells or cell to cell interconnections to fail
Why is the warranty for flexible solar panels different from rigid residential house panels?
Most flexible solar panels are made almost entirely of plastics that eventually separate and degrade over time and can be easily damaged due the additional stressors from being adhered directly to a surface.
More recently, advanced techniques have allowed flexible solar panels to improve on their product warranties and even beat the warranties of rigid solar panels despite the increased stressors they face. This is due to a combination of techniques such as:
- a fine wire mesh over the cells to protect the power output even if a cell is broken from blunt force or over-flexing
- glass fibres integrated into the solar panel polymers to reduce their expansion rates during thermal cycling
- sealing the edges of the panels as a thermoplastic so it is not possible for the panel to delaminate