Thanks, also it is often said that having a large earthed enclosure round the electronics reduces noise, would you agree? {(i refer to "being earthed" by an earth wire, and not the fact that its a metal post sunk deeply into the ground (earth)}
- - - Updated - - -
Don't think of moisture as being direct wetting per se. You get a pumping action as the enclosure heats up and cools down. As it heats, the air inside the enclosure expands and the pressure builds up, inevitably some air leaks out around the gasket and wiring entry glands. When it cools down again the reverse happens, humid air gets drawn in by the vacuum and condensation forms. Over many cycles, and there will be at least one per day, they can get pooled water in them. There is some merit in leaving a vent hole in position where direct ingress isn't possible.
Thanks, that rings the bell of good sense to me, that’s about the best explanation I’ve ever heard of the moisture problem in outdoor lighting.
When I worked at a LED beacon company, nobody could agree whether to conformally coat the PCBs or not…..we were getting failures of unknown cause, and people thought it might be moisture…as you know, the problem with conformal coating is that it does slightly result in heating the components up more…specially those that don’t have a mode direct connection to the heatsink.
I wonder if it’s a golden rule that all outdoor led lighting should be conformal coated, or coated in silicone?
- - - Updated - - -
Don't think of moisture as being direct wetting per se. You get a pumping action as the enclosure heats up and cools down. As it heats, the air inside the enclosure expands and the pressure builds up, inevitably some air leaks out around the gasket and wiring entry glands. When it cools down again the reverse happens, humid air gets drawn in by the vacuum and condensation forms. Over many cycles, and there will be at least one per day, they can get pooled water in them. There is some merit in leaving a vent hole in position where direct ingress isn't possible.
Thanks, that rings the bell of good sense to me, that’s about the best explanation I’ve ever heard of the moisture problem in outdoor lighting.
When I worked at a LED beacon company, nobody could agree whether to conformally coat the PCBs or not…..we were getting failures of unknown cause, and people thought it might be moisture…as you know, the problem with conformal coating is that it does slightly result in heating the components up more…specially those that don’t have a more direct connection to the heatsink.
I wonder if it’s a golden rule that all outdoor led lighting PCBs should be conformal coated, or coated in silicone?