What are the major problems observed in a PV module and how can it be resolved?

Problem 1 – Soiling/ Dust Accumulation

As the generation of the PV system is proportional to the sunlight reaching it, any dirt build-up over the solar arrays can substantially affect the system performance, reduce the energy output but more importantly reduce the life of the panels.

It is essential to clean the modules regularly to prevent energy loss. Clean solar panels ensure that the system generates optimum electricity. Areas that are generally dusty and polluted will require more frequent inspection and cleaning.

Dust accumulated on the solar panel causing soiling losses (Image Credit: GERMI)


The solar panels can be cleaned either using water (wet cleaning) or brush (dry cleaning). The points to be noted for both the above techniques are as follows:

  • The water must be free from particulates and physical contaminants that could damage the module surface.
  • Do not clean the reverse side of the module.
  • Use a soft sponge/ cloth to remove bird droppings, girt, tar if any on the module surface.
  • A soft sponge or rubber wiper should be used to dry the module surface after rinsing.
  • Cleaning should be carried out when the modules are in a cool condition to avoid any thermal shock which may cause cracks.
  • Do not sit, stand, or step on the module surface.
  • During dry cleaning, the dirt/ dust should not be scrubbed which may lead to scratching on the module surface.

Problem 2 – Shading

Any shading caused by the nearby objects including antenna, nearby trees, water tanks, clothes, poles, etc. reduces the output significantly. Thus the solar modules should be free from any shading preferably between 9:00 am to 5:00 pm.

Shading not only results in power loss but also reduces the life span of the solar modules due to hot spots.

Shading on the PV Panels due to the surrounding objects


  • At the time of installation, care should be taken that the solar system is not placed in the shaded area.
  • Analyse the generation data to identify any inconsistencies.
  • It is NOT recommended to cut any trees, however, the branches of the trees could be trimmed to avoid any shading.
  • Call your service provider in case you are not able to remove the shading.

Problem 3 – Module mismatch

In a solar system, the solar modules are connected in series and parallel, and any of the following mismatches results in the loss of generation.

  • Mismatch from orientation, manufacturing differences, aging, string configuration or soiling (dust).
  • Mismatch loss by using different module technology on the same string.
  • Differences in cell processing during manufacturing.
  • Cells or modules of the different rating or different manufacturer.
  • Different environmental conditions, partial shading of cells or modules.

Module mismatch owing to different technologies

The consumer should check that the solar panels are installed in a way that they have similar orientation, manufacturer, rating etc.

In case any mismatch is observed, the installer should be informed for making the necessary rectifications.

Problem 4 – Physical damages

It is required to check for any physical damages which might cause loss of generation. The damages can be identified by visual inspection and are mainly due to moisture ingress, corrosion, delamination, and hairline cracks. If any physical damage is observed, the installer should be informed for making the necessary rectifications.






Delamination and corrosion on PV modules

(Ref: Best Practices in Operation and Maintenance of Rooftop Solar PV Systems in India – GERMI)

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