9
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.
6.2 Maintenance
Renogy 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. Observe the maintenance instructions for all components
used in the system, such as support frames, charging regulators,
inverters, batteries, etc.
6.3 Replacing Bypass Diodes
Removing the bypass diodes should be done only by a competent PV
technician and after the module has been disconnected from the system.
Place module face down on a soft, flat surface Insert a 3mm flat
screwdriver into the slot on the junction box cover. (The cover has a
sign of screwdriver). Gently pull up the four slots until the cover been
opened.
Insert the 3mm flat screwdriver into a hole alongside of diode and
near one mounting hole of the diode, pry the screwdriver in the
opposite direction of diode and gently pull the diode up until the lead
comes free. Do the same in the other mounting hole of the diode, and
repeat until the diode is free.
Note the orientations of the polarity markings on the diodes.
Check the resistance of the diodes by using the digital multimeter’s
ohms scale. Resistance should be low in one direction, then when
leads are reversed on the diode’s terminals the resistance should be
high, as illustrated in the two pictures below. If a diode has a low
resistance in both directions, it is probably shorted. If it has high
resistance in both directions it is probably open. In either case it
should be replaced.
Replace a defective diode with a diode of the same type, and ensure
that its polarity making is oriented the same way as the original diode.
Finally, check the open-circuit voltage (Voc) of the module, as
described previously, and replace both covers.
