Avoid Using Fan-cooled Power Supplies in Outdoor LED Signs

8 May 2018
LED sign panel with MEAN WELL power supply

Fan-cooled power supplies may fail if used in outdoor LED signage.

Many LED sign panels imported into Australia use a MEAN WELL power supply. This is usually because of MEAN WELL’s reputation for reliability.

However, in several cases a fan cooled power supply has been used.

Fan-cooled power supplies draw in air to cool their vital electronic components.

If this air is cool and damp, as it often can be outside, then condensation can quickly form inside the power supply. This has the potential to cause a failure, which would not be covered by the warranty.

MEAN WELL has recently launched a brand-new series of ultra slim fan-less power supplies, which are ideal for LED signage applications.

You can learn more about these new power supplies by following the below link:

New Fan-less Power Supplies for Outdoor LED Signs

The new UHP series remains cool by conducting heat away through the metal housing of the LED sign panel. The minimum surface area required for adequate conduction is stipulated in the data sheet.


By using a UHP series power supply, LED sign manufacturers significantly reduce the likelihood of a power supply failing due to moisture ingress.

The most commonly used power supply used in imported LED signs appears to be the MEAN WELL RSP-320-5.

Unfortunately, it is not always possible to retrofit a UHP series power supply as the sign manufacturer may have not designed the panel, so that there is enough surface area in the design to dissipate heat way from the power supply.

If you find yourself in this situation there is a version of the RSP-320-5 available with a conformal coating. This is the RSP-320-5CC.

This helps reduce the potential of failure from moisture ingress. However, it should be noted that this is not a fool-proof solution.


The RSP-320-5CC is available through your local MEAN WELL sales representative.