Photovoltaic modules are photoelectric conversion devices that generate electricity as long as sunlight is present, and if they perform well in the first year, they will likely continue to perform well for a long time thereafter. However, there is one problem that can be unreliable. The reason for poor system performance reporting is the manufacturer's overestimation of the power generation of the modules. To date, there has been no case of a PV module operating beyond its useful life. If there is a problem, it is most likely in the combiner box of the module.

A complete account of PV module reliability issues should include issues ranging from vandalism to theft. Photovoltaic modules must be exposed due to their inherent function. In the case of installing photovoltaics on non-building structures (such as street lamps), they are usually installed independently. Therefore, they are vulnerable to damage by vandals. The possibility of vandalism and theft can only be avoided when the system is designed. Photovoltaic modules should be placed in inaccessible places and equipped with anti-theft locks.