Energy Tech


Panel abnormality detecting technology by drone inspection

What drone can realize

A drone equipped with an infrared camera photographs all panels of a photovoltaic power plant and make the inspection. It can detect any defects on a cell-by-cell basis as well as check the defective locations on the image, which can reduce the time until determination of the root causes.
Most of all, the biggest advantage to use a drone can be unnecessity to stop the power generation during the inspection. The loss of the power generation due to the inspection can be minimized.

Speedy – Reduction of inspection time –

Very high speed around dozens of minutes per 1MW realized to detect hotspots ※1, panels’ cracks, clusters and strings abnormalities.
Availability to check the video while shooting realizes on-site response quickly during the inspections.

Accurately – Overwhelming accuracy –

The inspection accuracy ※2(99.99%)by drone was proved to be same rate as the human inspection according to the original experiment by afterFIT.
Pinpoint identification of the abnormal panels’ locations accurately and quickly.

Low-cost – Reasonable price –

Significant reduction of the maintenance cost realized thanks to the availability with a small number of the inspectors and the speedy work.
The cost performance improvement can be led by the reduction of the maintenance costs along the profit enlargement from the power generation.

  • ※1.Hotspot …A kind of abnormality found in solar panels.
  • ※2.Accuracy …Accuracy rate of classification, which provides how correctly panels are classified into normal / abnormal in the all of them.The inspections by hand or drone were conducted at the same photovoltaic power plant respectively. The numbers of misidentified panels were 1/10,000 pieces in the both ways.

Strength of afterFIT

Expert knowledge – Expert assemblage -

afterFIT has been dedicated to research and analysis on photovoltaic power generation. We are, as it is called, expert assemblage on photovoltaics. Our employees who have been full-fledged expertise for “what a photovoltaic power plant should be” shall be in charge of ranges from the preliminary consultation to data analysis and subsequent consulting.

Network – Nationwide bases -

afterFIT has 12 branches nationwide and its employees reside in the sites. Thanks to unnecessity of long transportation and labor costs to the inspection point, lower costed drone inspection can be conducted than the other competitors.

Highly skilled pilots

Qualified persons who have been certified by drone manufacturers belong to afterFIT.They boast of their high skills not only in photovoltaic power generation but also in the field of drone technology. Approximately 73% of employees on-site are drone operators. Therefore, afterFIT can be also an expert assemblage for drone.
《Raptor Solar Contest 2018 Winner》

Latest tech – State of the art EL inspection introduced –

Introduced EL inspection ※1for drone as the pioneer in the industry. This is a state-of-the-art technology that only a few companies have launched in Japan. The inspection visualizes solar panel abnormalities such as micro cracks, PID phenomena, and breaking of interconnector.
The work time has drastically reduced by the combination with video shooting by drone comparing to the conventional way that each solar panel is shot with a still image and inspected one by one.

  • ※1.EL inspection… EL is short for Electroluminescence. Originally a method of detailed examinations that are carried out in process of solar cells production, utilizing the phenomenon that near infrared rays is emitted when current is applied to solar cells.

Examples of detectable defects

Obviously enables detection of abnormalities that are usually invisible at glance on the panels, by thermo-camera images shot by drone.
The followings are typical examples that drone is available for the inspection.


Phenomenon that some parts on the panels are heated due to imposition of a large resistance caused by some reasons.
The causes attribute to various factors such as dirt and fallen leaves adhesion and damage to panels. Some parts on the panels are heated as result of the prolonged inability to generate electricity. Damage of the panels or firing may happen if they are left in the state so that the immediate reaction can be required.

Cluster error

1 Cluster, that is the condition that power is not generated from 1/3 of the panels. Most of the cause attributes to peeling on the soldered joints, which leads to breaking or higher resistance of the cluster and short-circuit of the bypass diode so as to stop the power generation.
Because of the insufficient output the guaranteed value, it is eligible for free exchange according to the manufacturer's warranty.

Anomalies in the entire strings

1 Condition that the power generation in the all strings stops. The cause may be some defects in the junction box or an event that an abnormality of one panel may affect the power generation of the entire strings.
The string abnormalities directly lead to a decline in selling electricity volume so that enormous income may be lost if left as they are.


Customer support center
Inquiry form

afterFIT is an expert assemblage for photovoltaics. Please feel free to contact us even for any tiny inquires or queries.
The quotation can be made based on size and location of your power plant. Please contact us by phone, inquiry form or direct contact to our sales representatives.