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Solar FAQ - frequently asked questions

Questions & answers about solar modules and tests

Do you still have questions about solar modules in general testing solar modules in particular? In our solar FAQ you will find answers to frequently asked questions about flash tests, checking and testing solar modules. We also explain in detail how ground-mounted solar modules differ from solar modules on roofs. If you have any further questions, please do not hesitate to contact us.

The flash test is a procedure for testing the performance and efficiency of solar modules. A brief, intense flash of light is directed at the modules in order to measure the current-voltage characteristics and thus determine the performance of the modules under standard conditions.

The flash test can be used for a wide range of solar modules, including monocrystalline, polycrystalline and thin-film modules. This test method is suitable for determining performance and efficiency regardless of the module technology.

Minimum module size (W x L in mm): 800 x 890 mm

Maximum module size (W x L in mm): 1400 x 2750 mm

We come to you anywhere in Europe - whether to your warehouse, logistics centre, solar park in the field, roof system or similar. We are happy to work on an uncomplicated basis with a daily flat rate of € 2,500.00 plus VAT and travelling expenses from Elmenhorst.

Framed and frameless glass-glass or glass-foil modules, bifacial solar modules, monocrystalline or multicrystalline modules (including PERC types), thin-film modules

Of course, you can also send us the modules for testing. In this case, it is important to note that the customer is responsible for transporting the modules there and back and for unloading and recharging them. We test the delivered modules and charge €16.00 per module plus VAT and a flat rate for unpacking and packaging.

Yes, our XXL-Mobile Lab 5.0 from the German manufacturer MBJ combines a TÜV-certified IEC 60904-9 Ed.3 A+A+A+ long-pulse LED sun simulator with a high-resolution electroluminescence test in a very compact system.

Before the tests, the modules to be tested are selected and made available for the tests. The modules should be unpacked beforehand and the packaging material removed or cleaned. During the test, at least two motivated and qualified helpers must be on site in addition to our team to support us in handling the test modules. 

Our team requires a 230 volt power connection in the immediate vicinity of the test location. If this is not possible, please let us know so that we have an alternative on board. It is important that we have a safe and suitable environment for our mobile test laboratory.

Solar modules can be visually inspected for external damage such as cracks or fractures. In addition, power and voltage measurements as well as flash tests can be carried out to ensure that the modules are producing the expected energy.

Solar modules usually need to be replaced when their performance decreases significantly, which is normally the case after around 25 to 30 years. Another reason for replacement can be serious damage that impairs the functionality of the modules.

Solar modules lose power over time due to natural wear and tear, ageing and exposure to environmental influences. In addition, dirt, microcracks, delamination or hotspots can occur on the modules, which also leads to a loss of performance.

The performance of solar modules can be monitored and checked by carrying out electrical tests such as flash tests and thermal camera inspections. In addition, regular monitoring of the energy yield compared to the expected values is an important indicator of the modules' performance.

It is recommended that solar installations are thoroughly inspected and checked at least once a year to ensure that they are working properly. In regions with extreme weather conditions or heavy soiling, more frequent inspections may be necessary, for example every six months.

Damage to solar modules can be caused by various factors, including environmental stresses such as hail, storms and UV radiation. Mechanical influences, soiling, microcracks, hotspots or defects in the module construction can also lead to damage.

Testing on solar panels can identify various defects and problems, including cracks in the glass, delamination (detachment of layers), microcracks, hotspots (local overheating), discolouration and dirt deposits. In addition, electrical tests can reveal deviations in performance and possible interruptions in the cabling.

Still have questions? Ask us ...

We are your partner when it comes to questions about solar modules, flash tests and repowering. Please let us know what you would like to know.

What is the difference between ground-mounted solar modules and roof-mounted solar modules?

Ground-mounted solar modules and roof-mounted solar modules differ primarily in their installation environment and the associated requirements and possible applications. They are generally larger, heavier and achieve a higher yield. Here are some important differences:

Installation location

  • Ground-mounted solar modules are installed on open, flat surfaces, such as agricultural fields, fallow land, industrial plants or solar parks.
  • Rooftop solar modules are installed on the roofs of buildings, houses or other structures.


  • Ground-mounted solar modules require special frame structures or mounting frames to fix and align them on the ground.
  • Solar modules on roofs are usually installed directly on the roof and can be laid flat or mounted at a certain angle.

Alignment and inclination

  • Ground-mounted solar modules can be aligned and tilted so that they receive the maximum amount of sunlight.
  • Solar modules on roofs often have to follow the existing roof pitches and orientations, which can affect their efficiency.

Space requirement

  • Ground-mounted solar modules require more space and are therefore more suitable for larger areas.
  • Rooftop solar modules utilise the limited space on building roofs more efficiently and are therefore ideal for urban environments.

Earnings potential

  • Ground-mounted solar modules often have a higher yield potential as they can be optimally aligned and have less shading.
  • Solar modules on roofs can be shaded by buildings or surrounding structures, which can affect their performance.

Building regulations

  • The installation of solar modules on roofs is often subject to stricter building regulations and authorisation procedures, especially in urban areas.
  • Ground-mounted solar panels can have fewer bureaucratic hurdles, but must also comply with certain regulations and environmental requirements.

The choice between ground-mounted solar panels and rooftop solar panels depends on several factors, including available space, geographic location, budget constraints and desired energy production. Both options have their advantages and disadvantages and the decision should be made on an individual basis.

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