Product Manual

6. Commission and Maintenance

6.1 Blocking diodes and bypass diode

Blocking diodes prevent current flowing from the battery to the module when no electricity is being generated. It is recommended to use

blocking diodes when a charging regulator is not used. Your specialist dealer can advise you the suitable types.

In systems with more than two modules in series, high reverse current can flow through cells that are shaded partially or totally when

part of a module is shaded and the rest is exposed to the sun. These currents can cause the affected cells to get very hot and could

even damage the module. To protect module from such high reverse currents, by-pass diodes are used in module. All modules have

bypass diodes already integrated in the junction box. In the unlikely event of diode failure, a replacement can easily be made.

Protect yourself from electricity shocks while debugging or maintaining the solar power system.

6.2 Testing, commissioning and troubleshooting

Test all electrical and electronic components of the system before using it. Follow the instructions in the guides supplied with the

components and equipment.

Testing modules connected in series before they are connected to system.

Check the open-circuit voltage of every series module by a digital multi-meter (fluke 170 series are recommended). The measured

values should correspond to the sum of the open-circuit voltage of the individual module. You will find the rated voltage in the technical

specifications of the type of the module used. If the measured value is significantly lower than the expected value, please proceed as

described under “Troubleshooting an excessively low voltage”.

Check the short-circuit current of every series circuit. It can be measured directly by a digital multi-meter (Fluke 170 series are

recommended) connected in the two terminals of series circuit or module, or with any load such as PV illumination to make a rough

measurement. Attention, the rated scale of the ammeter or the rated current of load should be more than 1.25 times of the rated short-

circuit current of series module. You will find the rated current in the technical specifications of the type of module used. The measured

value can vary significantly, depending on weather conditions, the time of day and shading of the module.

6.3 Troubleshooting low voltages

Identify the commonly low voltage and excessively low voltage. Commonly the low voltage mentioned here is the decrease of open-

circuit voltage of the module, which is caused by the temperature rising of solar cells or lower irradiance. Excessively low voltage is

typically caused by improper connections at the terminals or defective bypass diodes

First, check all wiring connections to make sure it is not open-circuit or is not connection well.

Check the open-circuit voltage of each module:

Fully cover the modules with an opaque material.

Disconnect the wiring at both terminals of the modules.

Remove the opaque material from the module to be checked and measure the open-circuit voltage at its terminals.

If the measured voltage is only half of the rated, this indicates a defective bypass diode. Refer to ‘Testing and replacing bypass diodes’.

In the case of not very low irradiance, if the voltage across the terminals differs from the rated value by more than 5 percent, this

indicates a bad electrical connection.

6.4 Maintenance

We recommends the following maintenance in order to ensure optimum performance of the module:

Clean the glass surface of the module as necessary. Always use water and a soft sponge or cloth for cleaning. A mild, non-abrasive

cleaning agent can be used to remove stubborn dirt.

Check the electrical and mechanical connections every six months to verify that they are clean, secure and undamaged.

If any problem arises, have them investigated by a competent specialist. Attention, observe the maintenance instructions for all

components used in the system, such as support frames, charging regulators, inverters, batteries etc.