What are the Warranties and Certifications I should look for in my rooftop PV system?

Warranties and Certifications

A rooftop PV system is made up several components each of which have their own performance parameters. We provide a list of the prominent warranties and certifications for each component in the table below.

Warranties Certifications
Solar Panels
Modules are typically warranted against manufacturing defects for a period of 10 years. In addition, their power output is also guaranteed with performance warranties up to 25 years. The performance warranties offered are of two types

  • Standard Warranty : minimum performance of 90% of the rated output for around first half of 25 years, and 80% of the rated output for the remaining of the 25 years
  • Linear Warranty : 25 year performance warranty that guarantees a maximum degradation of 2.5%  in the first year, and some value in the range of 0.5–0.7%/y thereafter

 

The crystalline PV module (which are predominantly used in rooftops over thin-film modules) should be certified to comply with

  • IEC 61215/IS 14286 – Design qualification and type approval
  • IEC 61730 – Safety
  • IEC 61701/IS 61701 – Salt mist corrosion testing (for panels installed in coastal areas or in maritime applications)

Panels should also be supplied with the MNRE mandated RFID tag that allows the panels to identified and tracked to the manufacturer for verifying performance.

Inverters
Most inverters come with a standard warranty cover of up to 5 years. This warranty covers the defects or damages that may occur to the inverters parts. Inverter Manufacturers can also offer you extended warranties at a premium, which can cover your inverter up to 7-10 years.
  • IEC 61683/IS 61683 – Efficiency
  • IEC 60068-2 (1, 2, 14, 30) – Environmental testing (Cold, Dry heat, Change of temperature, Damp heat cyclic)
Mounting structures
Mounting structures are typically warranted for 1 year, with optional extension up to 5 years.
Batteries
Batteries are typically warranted for 1 year, with optional extension up to 5 years. While battery certifications would depend on the application for which they are required, consumers can perform simple checks to verify if the battery is genuine

  • Capacity-weight – Capacity should correspond with the weight e.g., a 100 Ah battery should weigh about 32 Kgs.
  • Batch number – This should be embossed (and not provided through a sticker) on the body
Cables
Cables are typically warranted for 1 year, with optional extension up to 5 years.
  • IEC 60227/IS 694 – General test and measurement of PVC cables
  • IEC 60502/IS 1554 (Part I & II) – Working voltage up to and including  1100 V and UV resistance for outdoor installation of PVC cables
Junction Boxes/Enclosures for Inverters/Charge Controllers/Luminaries
Junction boxes and enclosures are typically warranted for 1 year, with optional extension up to 5 years.
  • IP 54 (of IEC 529) – Outdoor use
  • IP 21 (of IEC 529) – Indoor use

The certification for each component can be found on the datasheet for the component.

 Expected lifetime of rooftop PV plant components

Rooftop PV plants have no moving parts and therefore don’t suffer from wear and tear, making them extremely reliable. The expected lifetime for the major components in your rooftop solar PV system is given below

  • PV modules – These should last 25 years, or even longer
  • Inverter – This is the only major component in the rooftop plant that will require replacement during the lifetime of the plant. Typical life is 5-10 years
  • Mounting structures – These should last the full 25 years of the plant’s lifetime
  • Batteries – Battery backups can last as long as 10 years with careful maintenance, but 3-5 years is a more typical lifespan

 Examples of component failure

While solar PV plants have no moving parts, the components of a plant can fail and require replacement due to several factors. A few examples are given here

  • Modules – Leakage of current into the frame of the module, resulting in 20-50% reduction in power output
  • Inverters – Capacitor failure due to aging of electrolytic materials
  • Junction boxes – Improper fixing on panel causes the box to fall off the panel, creating a fire hazard

 Failures not covered by warranty

Not all component failures are covered by warranties. These are typically due to poor design of the rooftop solar plant. Examples include

  • Modules – Shadows falling on the panels causes them to burn out (more details here)
  • Connectors – Overheating caused by poor fastening
  • Cables – Squirrel or bird damage

 

Takeaways
  • Solar modules come with 5-year warranty against manufacturing defects as well as performance warranty of 90% of rated power output for 10 years and for 80% of rated power output up to 25 years
  • Other components (inverters, batteries, junction boxes, etc.) come with 1-year warranty extendable to 5 years
  • There are several IEC or IS standards that the various components of the solar system should comply with
  • Inverters are the only major component of a PV plant that are expected to be replaced within the lifetime of the plant
  • Batteries, if used, will also need to be replaced. They also require careful maintenance
  • Not all damage is covered by the manufacturer’s warranty e.g., shadow damage

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India Renewable Energy Expert