Customer support

Frequently asked questions

For orientation in the selection of photovoltaic modules, please refer to the power values given in watts (W), sometimes also indicated as Watt Peak (Wp), as well as the voltage values in volts (V). The solar module must not exceed the output power of the inverter (AC power) by more than 30%. In addition, the open circuit voltage (Uoc / Voc) of the module must be within the voltage range of the inverter and must not exceed 95 % of the maximum voltage of the inverter. If the solar modules provide a higher current than the inverter puts out, the inverter automatically downregulates the electric current. Automatic regulation does not cause any damage to the device.

In practical terms, this means that an INV500-90 inverter can be connected to photovoltaic modules with up to 700 watts power and an open circuit voltage of 84 volts. The inverter type INV315-50 can be connected to solar modules with up to 400 watts. Also, with the INV315-50, the maximum input voltage of 50 volts must not be exceeded. This means that PV modules with a maximum open circuit voltage of 44 volts should be used to prevent damage to the inverter.

As soon as the power delivered by the solar module exceeds the absorption limit of the inverter, it will automatically switch to maximum and leave the additional power settings unchanged. In any case, it is preferable to choose a photovoltaic module exceeding the inverter in maximum power, because solar modules are rarely optimally aligned. On balconies, in particular, they usually yield a reduced power output. The optimal orientation for a solar module is to the south with an inclination of 30°. Even with optimal orientation, the maximum power values of a PV module are rarely achieved, as factors such as clouds or shading also reduce the power yield.

There are several ways to connect solar modules and inverters:
  1. Series connection
    In this type of connection, two or more PV modules are connected to each other by connecting the negative cable of one module to the positive cable of the next module. The end of the first and the last module are connected to the inverter. Next, the inverter is connected to the AC line, which is in turn connected to the power grid.
    Please note that powers and voltages add up to each other when connected in series. If the open circuit voltage of the modules connected in series is higher than the maximum input voltage, the inverter will take irreversible damage!

  2. Parallel connection
    The PV modules can be connected via a y-cable in a minus-to-minus and plus-to-plus pattern. The positive and negative cables of the Y string are connected to the corresponding connective pieces of the inverter.

The flashing code indicates the current operating status of the inverter. The signals provide information about the current feed-in power of the inverter as well as a possible malfunction. The meaning of the individual flashing signals can be found in the operating manual of the respective inverter on page 7.

Links to operating manuals:

This can happen for different reasons, most commonly one of the following:

  1. Disturbances in the power grid
  2. Ripple control signals in the power grid
  3. Recurrent shading
  4. Broken cables
  5. Loose contacts in plug connections
  6. Corrosion of plug contacts
  7. Dirt particles on connectors of cables
  8. Devices interfering with the network (sewage treatment plant, large construction site, substation, transformer station, etc.) in the immediate vicinity
  9. Too many consumers (freezer, washing machine, dishwasher) connected to the same phase as the inverter
  10. Interfering communication signals (D-LAN, smart meter)
  11. Unsuitable cable length (see DIN VDE-0100-410)

We recommend checking all points (especially 4. and 5.). In most cases, a restart of the inverter eliminates the error pattern.

You can perform a restart as follows:

  1. Disconnect the inverter from the mains
  2. Disconnect inverter from solar module
  3. Wait for at least 10 minutes
  4. Connect solar module to inverter
  5. Connect inverter to house mains

After approx. 10 minutes the inverter will be fully powered up again. If the error does re-occur, please contact us using the return form at the bottom of this page.

The connections between the solar module and inverter feature snap switches. They can be easily released with a H4 unlocking tool (see picture). If you do not have a fitting unlocking tool, you can also disconnect the inverter from the house-grid during the night.

If you hear a humming noise, the device is working properly. Due to slight tolerances in the manufacturing of magnetic components, devices may hum to a greater or lesser extent, caused by the frequency of the power grid of 50 Hz.

For devices produced as of 2018, we provide a warranty of 10 years.

For devices produced before 2018, the warranty period is 5 years.

Return form

We are sorry if a technical error has occurred. As soon as you send us the inverter, we will check it immediately in our laboratory. If a defect is found, we will replace or repair your inverter free of charge within the warranty period. Please note that we do not provide warranty on devices with opened casing or damaged seals. If we consider the defective device to be faultless or if the malfunction was caused by user error, we will charge you an expense fee of at least 50 € plus VAT and, if applicable, material costs.

If you wish to solve any problem with your inverter yourself, please refer to our checklist:

After you fill out the contact information in the form and send it to us, we will send you the return form to the email address you provided.

We are sorry if a technical error has occurred. As soon as you send us the inverter, we will check it immediately in our laboratory. If a defect is found, we will replace or repair your inverter free of charge within the warranty period. Please note that we do not provide warranty on devices with opened casing or damaged seals. If we consider the defective device to be faultless or if the malfunction was caused by user error, we will charge you an expense fee of at least 50 € plus VAT and, if applicable, material costs.

If you wish to solve any problem with your inverter yourself, please refer to our checklist: