Features
In electroluminescence (EL) inspection, we energise the PV modules so that they emit light like an LED. This light is invisible to the human eye, hence we use a special camera to detect it. During the inspection, we generate an image for each individual PV module. These images provide information about ‘hidden’ defects such as cell cracks or production faults that would remain undetected without the EL inspection. We are different from our competitors because our DaySy EL process is done during the day, while EL inspections are usually performed at night to minimise the effect of extraneous light. We hold international patents on our DaySy daylight EL.
With our latest, high-resolution camera, we can detect even the smallest cracks and defects in the solar cells.
Not only hail, but also incorrect installation leaves its mark! We check your PV system in its installed state for hail damage, manufacturing or mounting defects that are invisible to the eye. In most cases, we can identify the cause based on the damage pattern.
We inspect every accessible PV system in its installed state:
We also inspect palletised modules for transport damage on delivery. By performing inspections, we detect even the smallest defects that may only affect the energy yield in years to come.
Step 1: Contacting us
You describe the problem to us, e.g. hail, installation damage, vandalism or reduced yield. We will get back to you promptly and discuss your concerns.
Step 2: Inventory
You send us photos and documents of the affected system. The string diagram and a power connection are particularly important. If the string diagram is no longer (correctly) available, we can also determine the position of the PV strings during the inspection with a little extra effort. If no power supply is available, we will bring a generator with us.
Step 3: Quote
We will draw up a suitable quote for you based on the inventory.
Step 4: Inspection
We arrange the inspection date depending on the weather. When we arrive, the system manager instructs us on the conditions on site and we then carry out the inspection ourselves. This involves powering entire PV strings with a powerful power source and photographing each module individually with the DaySy special camera.
Step 5: Analysis with expert report
We analyse the EL images in the following days and prepare a report with a recommendation for action. Our report also documents the location, type and, if possible, the cause of the recognised defects. In the event of hail damage, our expert reports are covered by many insurance companies.
EL/PL Inspection FAQs
Do you want to know the actual condition of your photovoltaic system? Our most frequently asked questions about Electroluminescence and Photoluminescence inspection (EL/PL inspection) explain when, how, and why this diagnostic method is worthwhile.
Luminescence refers to the emission of photons as a result of the recombination of electrons and holes within a semiconductor material. When energy is supplied to a solar cell, electrons are excited to higher energy levels. As they return to the valence band, the excess energy is emitted as photons. Electroluminescence (EL) excites the photovoltaic module electrically, causing it to emit light in the near-infrared range. Areas that emit less light indicate an increased series resistance. In Photoluminescence (PL), the excitation is caused by light, and darker areas appear as a result of lower shunt resistance. Both methods complement each other perfectly for precise fault diagnostics.
A photovoltaic inspection is recommended in the following cases:
Using Electroluminescence and Photoluminescence, even the smallest defects become visible — including those that may not yet cause power loss but could lead to degradation under wind or snow load. Typical findings include:
The Electroluminescence and Photoluminescence inspection provides numerous benefits:
Please contact us if you are interested.We will be happy to advise you!
Our blog contains various entries on the subject of photovoltaics. Take a look and find out more.
From backyard tests to PV power plants: Solarzentrum Stuttgart has successfully completed the first drone test flights for electroluminescence (EL) and photoluminescence (PL) inspection under daylight conditions – including meaningful PL results during cloudy winter weather.
After a hailstorm, microcracks in PV modules may remain unnoticed – an electroluminescence inspection makes them visible.
A guideline to prepare the site for a daylight EL inspection, ensuring an efficient workflow and having the site organised afterwards in the interests of the site owner.
Solarzentrum Stuttgart inspects modules after delivery at four 50 MWp PV sides in Spain.
The Solar Center ensures sustainable energy supply through the installation of a PV system in Stuttgart-East.
The Solarzentrum Stuttgart inspects a 1 MWp rooftop system in northern Germany.
Solarzentrum Stuttgart develops and tests the new fully automated daylight electroluminescence robot for inspecting ground-mounted systems.
