I am doing a project where I will have quite a few XML emitters mounted on stars from cutter. The project calls for 36 to be exact. I am starting to wonder what kind of heat sinking I will be needing to look into. My design has the housing for the emitters playing a large part in the heat sinking. Just wondering how much housing I will need to keep that many emitters under control. I will be driving them @ 3a and the housing is 1/2" aluminum on 3 sides with cooling fins machined into it.
Heatsinking an XML.
- Thread starter DKlaser
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Sounds like a U shaped Track. If so how much space will there be between emitters?
Coating the aluminum with a high emissivity coating will increase the dissipation of heat.
Also I just saw some info on putting cuts through the heatsink so heat from one LED doesn't spread to anothers fins; air gaps
lucca brassi brought it up here
Coating the aluminum with a high emissivity coating will increase the dissipation of heat.
Also I just saw some info on putting cuts through the heatsink so heat from one LED doesn't spread to anothers fins; air gaps
lucca brassi brought it up here
It is not u shaped track right now but will be soon. It is 1/2" wall square tube that is 4" square. the plan is to machine most of one side out so I can attach a poly carbonate window. I will machine heat sinking fins maybe 1/4" deep and 1/8" wide along the entire backside right behind the emitters. The total length of the housing is 24" long and I plan on doing two rows one on top of the other of XML's with 18 in each row. The reflectors are 30mm in diameter so I think the spacing will be right around 34mm or 1.33" between centers of the emitters. So not a ton of spacing. The stars they are mounted on are 20mm. I am not trying to run these for hours maybe just 10 or 15 minutes at a time.
I also have enough depth to mount these on another plate that I can mount inside the housing like say a 1/2" thick copper plate. How well would that transfer the heat into the aluminum???
I also have enough depth to mount these on another plate that I can mount inside the housing like say a 1/2" thick copper plate. How well would that transfer the heat into the aluminum???
MikeAusC
Enlightened
Each emitter is putting out the same heat, so each will be at the same temperature, so there will be no heat flow between adjacent emitters, so there's no point in cutting isolating slits.
This is somewhat just because I am wondering and somewhat random thoughts:
- Will the unit be mounted horizontaly or vertically?
- Will the cooling fins be horizonltal or vertical?
- 18 LEDs along 24 inches gives around 1.5 inches of length each and a back profile that is 2 inches of fins and a below/side/above profile that is um, maybe 2 inches. so that is around 6 squar inches of Al to act as a heat exchanger (plus fin area) to the outside air. 1/4 inchs deep by 1/8 wide should give you around 3 times as much area for that back portion, so lets put htat total up to 12 square inches total. based on the size of a maglight (and it's surface area near teh LED) I don't think you woudl end up with enough passive cooling; you woudl need some air movment from a fan. I coudl be wrong, don't take this as the only oppinion.
- i'd be interested what you plan to do with this. and why you want 30+ lumens.
- I'm trying to think of what object dissapates 360 watts of heat but the only thing i can come up with is a quarter of a toaster oven or a gaming computer.
- Will the unit be mounted horizontaly or vertically?
- Will the cooling fins be horizonltal or vertical?
- 18 LEDs along 24 inches gives around 1.5 inches of length each and a back profile that is 2 inches of fins and a below/side/above profile that is um, maybe 2 inches. so that is around 6 squar inches of Al to act as a heat exchanger (plus fin area) to the outside air. 1/4 inchs deep by 1/8 wide should give you around 3 times as much area for that back portion, so lets put htat total up to 12 square inches total. based on the size of a maglight (and it's surface area near teh LED) I don't think you woudl end up with enough passive cooling; you woudl need some air movment from a fan. I coudl be wrong, don't take this as the only oppinion.
- i'd be interested what you plan to do with this. and why you want 30+ lumens.
- I'm trying to think of what object dissapates 360 watts of heat but the only thing i can come up with is a quarter of a toaster oven or a gaming computer.
Going to be mounted horizontaly.
I can machine them either way.
This is going on a vehicle so it would have air moving over it most of the time. With the depth of the housing I have plenty of room and probably will attach all this to a removeable plate made out of aluminum that would add another .5" to the depth of the material that the emitters are mounted on. I would attach the emitter plate inside the housing with screws and a layer of thermal paste between it and ther housing. Do you think this would help any or make it worse since there is another plate joined to the housing? And as far as why, well..... why not... if I am already going to all this trouble I want it to be impressive. Also depending on how this turns out there will be another just like it sitting right next to it on my light bar.
I can machine them either way.
This is going on a vehicle so it would have air moving over it most of the time. With the depth of the housing I have plenty of room and probably will attach all this to a removeable plate made out of aluminum that would add another .5" to the depth of the material that the emitters are mounted on. I would attach the emitter plate inside the housing with screws and a layer of thermal paste between it and ther housing. Do you think this would help any or make it worse since there is another plate joined to the housing? And as far as why, well..... why not... if I am already going to all this trouble I want it to be impressive. Also depending on how this turns out there will be another just like it sitting right next to it on my light bar.
Oh my... really vehicle mount! I thought you were trying to light up a warehouse space
I'm sure you'll be fine with a 4" finned square tube even at low speeds. Maybe not rock crawling speeds, But then you'd probably want lights on all sorts of strange angles to see where your tires are for that and not straight ahead.
I'm sure you'll be fine with a 4" finned square tube even at low speeds. Maybe not rock crawling speeds, But then you'd probably want lights on all sorts of strange angles to see where your tires are for that and not straight ahead.
