global solar distribution
Finding replacement modules made easy

Finding replacement modules made easy

The search for suitable replacements for damaged modules that are no longer available presents many people with new challenges. Here are some tips for finding possible alternatives.
Basically, the replacement module must physically fit on the roof on the one hand, on the other hand it must be electrically similar.


Physical parameters

In terms of dimensions, not only the width and length but also the frame height play a role, as otherwise the already installed clamps of the substructure can no longer be used. If these conditions are met, the electrical values must be compared.


Electrical conditions

Of course, it is ideal if the electrical values are as identical as possible. Since this is often not possible, care must be taken to ensure that the short-circuit current is not lower than that of the existing system. Reason: The electric current flow (unit: Ampère (A)) can be seen as the water flow in a garden hose.

As with the hose, this current is identical throughout the entire string, so that the weakest link in the series of solar modules determines the total flow rate.

The general consequence of this needle eye principle, similar to standing literally on the tube, is that the entire flow is impaired.

This not only results in a loss of yield, but also endangers the safety of the plant. A module with a lower current would act as a resistor where power drops, heats up and, in the worst case, can burn.

An example:

A 180W mono module is defective. This one no longer exists. A replacement module would be the 200W module, as it has a slightly higher current than the defective old module.

Electrical data 180 Mono 200 Mono
Nominal power Pmpp [WP] 180,00 200,00
Nominal current Impp [A] 5,03 5,50
Nominal voltage Umpp [V] 35,83 36,49
Short circuit current Isc [A] 5,53 5,85
Open circuit voltage [V] 43,35 45,62
Module conversion efficiency ŋ 14,01 % 15,41 %
Max. system voltage 1000 V 1000 V


At the same time, it should of course always be ensured that the inverter supports the new constellation, i.e. that voltage and current limits are observed.

09.03.2018 14:57
by Maik Wünsche

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