Heatsinks

[George Simmons]

I live in central Minnesota where winters are rarely warm - above-freezing temps are uncommon during the lighting season. How necessary are heatsinks given that the control boxes will be outdoors? Will the light-duty heatsinks work as well in cold climates as the heavy-duty heatsinks?

Thanks,

George Simmons

[-klb-]

Unfortunately heat sink requirements are more about surface area and thermal conductance than ambient temperatures. Yes, higher ambient temperatures will increase heat sink requirements somewhat, but the difference between no heatsink, and the low power heatsinks is huge. And the difference between the low power and high power heatsinks is also quite significant. The high power ones are at least twice the thickness (much higer conductance to carry heat away from the junction) and about 4x the surface area.

I have not personally seen any reason to question the 2A per channel limit with low power heatsinks, and 8A per channel with the high power.. However, I do think that with the low power heatsinks, there is almost an implicit assumption that not all channels will go to 2A. The total surface area is so much smaller on the low power heatsinks.

- Kevin

[George Simmons]

Thanks Kevin. I'm trying to figure out the most bang for my bucks, but I don't want to cut corners that shouldn't be cut.

George Simmons

[Denny]

I used the PC boards this year with the low heat sinks, BUT I used them to control only LEDs. Had no problems.