How do you cool an switch mode LED light in an enclosed beacon?

[grizedale]

Hello,

How do you cool the LEDs and the switch mode LED driver which are present inside a LED beacon like this.?

https://www.lightbar-shop.co.uk/Britax-LED-Beacon-80.html

The power dissipation is 10W, and there is no internal fan, and no ventilation holes whatsoever.

The diffusor is perspex, so unfortuately is thermally insulating.

Also, this product is used out in the sunlight, so suns rays will get trapped inside and make it super hot.

Even if you put a big aluminium heatsink in there, where is it going to conduct the heat away to?

And do you agree that putting the LED Driver PCB on the same heatsink that the LEDs are on is bad practice, since the LED driver will simply run too hot?

 

[betwixt]

Is this a flashing beacon? The web page doesn't say.

If it is flashing, the 10W is probably the power consumption when the LED is on, the average will depend on the on/off timing but will be somewhat lower. I'm not sure it would need a power supply as such, with either 12V or 24V available it would make more sense to simply pulse the current through a resistor using a simple timing circuit.

Brian.

 

[chuckey]

I have never had one of these beacons apart so this is guess work. I think to get all round illumination you will need many LEDs, so heat sink them to a central pillar which terminates through the base and hopefully takes the heat outside.
Looking at the thermal conductance of polycarbonate .2W/m per degree C. So if the case is 2mm thick its K is .2 X 500 W/m^2. lets say its total surface area is about .2 m^2, which then works out to be 20W/deg C. I don't think there is a problem if the case is 150mm high and 100 mm diam. there will a temperature drop across the thickness of the case of 1 deg C per 20 W. The problem is to get the heat from the LEDs to the inner wall of the case, perhaps some contact fingers in the black base?
Frank
Frank.