Every minute a photovoltaic system operates with reduced output, because of

  • defects
  • processing defects
  • material defects
  • degradation

implies significant costs for the operator.

With our mobile test laboratory and the technical measuring equipment we offer an on-site inspection of your solar panels. A new developed process is the rooftop electroluminescence that we offer in combination with the mobile test laboratory. The system can be checked in operation, also in the night.

We offer the following test methods:

On-roof thermography - different error indications
On-roof thermography - different error indications


Thermography is an imaging method to illustrate surface temperatures of objects. The temperature difference in the module respectively in the whole system is illustrated with the high-resolution infrared camera.

Characteristic curve measurement

With the characteristic curve measurement device we can determine values like the actual performance, the short-circuit current as well as the open circuit voltage and convert them into standard test conditions (STC). From the comparison of the actual and the reference characteristic curve we can draw conclusions to the condition of the photovoltaic modules.

Characteristic curve measurement of an intact module
Characteristic curve measurement of an intact module
Electroluminescence - damage by hail
Electroluminescence - damage by hail

Electroluminescence measurement

At the electroluminescence measurement we use a high-resolution camera to illustrate defects that are not visible with the naked eye. The system can be checked in operation. Visible defects are:

  • capillary cracks of the silicon wafers
  • damages by hail
  • defective edge insulation of the solar cell
  • break of the contact finger

Flashing of the modules

Flashing the modules is used to determine the rated power of a solar cell or of a solar module. With this the power loss of a module and thereby of the whole system can be detected.

Rooftop electroluminescence

For this measurement method there is no disassembly of the modules necessary – they were checked on the spot. SYSWE is one of the first providers in Germany who has the ability to check your system in the night. Therefore a framework with the measurement device is drawn on the module. Only when the defects are too strong the module has to be disassembled and can be checked in our mobile test laboratory.

On-roof electroluminescence
On-roof electroluminescence

Insulation resistance measurement

PV systems with transformerless inverters are not galvanic separated from the grid at feed-in operation. According to the VDE standard DIN VDE 0126-1-1 a certain limiting value of the insulation before grid connection must be observed. The limiting value is geared to the current installation instructions.

Because of the increasing plant size and in consequence the major generating surface as well as the parallel connection of the modules, the insulation resistance is decreased. This maybe implicates that the inverter is not allowed to connect to the grid, although the system operates proper.

VDS Vertrauen durch Sicherheit

SYSWE is your partner for the inspection of your PV system. We are an approved technical expert for PV systems as well as electro thermography (VdS) and certified for the disturbance-free testing according to DIN EN 473 IT class 2.

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Stephan Neitzel
Stephan Neitzel

Tel.: +49 4222 - 805 805 0

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