cooling a really hot led + dim ?

Abou · Feb 17, 2019

Hello,

I have a led like this one :

€ 8.04 16% de réduction|100 w LED Iode Tungstène Lampe Étanche Projecteur Extérieur Projecteur dans Éclairage industriel de Lumières et Éclairage sur AliExpress.com | Alibaba Group - https://fr.aliexpress.com/item/100-w-LED-Iode-Tungst-ne-Lampe-tanche-Projecteur-Ext-rieur-Projecteur/32948938986.html?spm=a2g0w.search0204.3.283.6bbc707fl3ew0J&transAbTest=ae803_4&ws_ab_test=searchweb0_0%2Csearchweb201602_3_10065_10068_319_317_10696_10084_453_10083_454_10618_10304_10307_10820_10821_537_10302_536_10902_10843_10059_10884_10887_321_322_10103%2Csearchweb201603_45%2CppcSwitch_0&algo_pvid=2ce10f6a-32ee-475e-9495-43a20fcd1afc&algo_expid=2ce10f6a-32ee-475e-9495-43a20fcd1afc-43

It is really hot after a few seconds, I was wondering how can I cool it? What is the best solution, a fan or a radiator? I'm a newbie...
And is it possible to add a dimmer? Which one?

Thank you very much for your help !

SparkyChick · Feb 17, 2019

If you're using that thing outside an enclosure it's a death trap as some of the terminations on the board will be at mains potential, so depending on the use of it, it may be advisable to seek an alternative means of illumination.

As to why it gets hot, there are 48 LEDs on each board, so if it is genuinely consuming 100W, that's approximately 50W per board, and consequently approximately 1W per LED. That is a lot of power (as an example, a soldering iron is 25W typically and get's plenty hot enough to melt low melting point alloys.

You could potentially fix a heatsink to the rear of the unit and add some forced air circulation, but based on the design I wouldn't both, I'd look for an alternative. They certainly shouldn't be used as they are shown in the three usage examples.

Abou · Feb 19, 2019

Thanks for your answer.

I wish I could use this led for non-professional photo shooting, with a umbrella etc.
In fact mine is a little different but I think it's the same thing, exept the wire are glued.

Dropbox - led.jpg - https://www.dropbox.com/s/p8jwwjjxisqyzif/led.jpg?dl=0

Marvo · Feb 21, 2019

That thing has built in drivers so you'd need to use a leading or trailing edge dimmer which will only work if the drivers were designed to be dimmable. From what I can see it's almost certain a dimmer won't work.

It looks like the unit is designed to be built into a light fitting and mounted onto a heat sink. It's almost like an OEM sub assembly that's normally supplied to manufacturers for them to build their own light fitting around but in this case they're selling as a flood light suitable for an end user....

If it is designed to be mounted onto a heatsink or bulky metallic fitting it won't last long if you run it without one. It's doubtful even using a fan blowing air across it will be effective enough to prevent damage to the COB LED assemblies due to local heat build-up.

alasdairp · Mar 10, 2019

Marvo said:
That thing has built in drivers so you'd need to use a leading or trailing edge dimmer which will only work if the drivers were designed to be dimmable. From what I can see it's almost certain a dimmer won't work.

It looks like the unit is designed to be built into a light fitting and mounted onto a heat sink. It's almost like an OEM sub assembly that's normally supplied to manufacturers for them to build their own light fitting around but in this case they're selling as a flood light suitable for an end user....

If it is designed to be mounted onto a heatsink or bulky metallic fitting it won't last long if you run it without one. It's doubtful even using a fan blowing air across it will be effective enough to prevent damage to the COB LED assemblies due to local heat build-up.

Abou said:
Hello,

I have a led like this one :

€ 8.04 16% de réduction|100 w LED Iode Tungstène Lampe Étanche Projecteur Extérieur Projecteur dans Éclairage industriel de Lumières et Éclairage sur AliExpress.com | Alibaba Group - https://fr.aliexpress.com/item/100-w-LED-Iode-Tungst-ne-Lampe-tanche-Projecteur-Ext-rieur-Projecteur/32948938986.html?spm=a2g0w.search0204.3.283.6bbc707fl3ew0J&transAbTest=ae803_4&ws_ab_test=searchweb0_0%2Csearchweb201602_3_10065_10068_319_317_10696_10084_453_10083_454_10618_10304_10307_10820_10821_537_10302_536_10902_10843_10059_10884_10887_321_322_10103%2Csearchweb201603_45%2CppcSwitch_0&algo_pvid=2ce10f6a-32ee-475e-9495-43a20fcd1afc&algo_expid=2ce10f6a-32ee-475e-9495-43a20fcd1afc-43

It is really hot after a few seconds, I was wondering how can I cool it? What is the best solution, a fan or a radiator? I'm a newbie...
And is it possible to add a dimmer? Which one?

Thank you very much for your help !

IF you are still around - this is for the LAMP ONLY (see the French text) not any casing. It is not suitable for general public use. It needs to be safely cased, heatsinked and probably fan cooled.

"Lampe SEULEMENT, d'autres accessoires démo dans l'image n'est pas inclus." Eeven if you don't speak French, Google translate does just fine:
"ONLY lamp, other demo accessories in the picture not included."

That is why it was just 8 Euros!