Best Way to Get Rid of 50W of Heat

[Wolfman29]

Hey everyone.

So I got a 40W 808nm diode array recently, and I am going to make this a really nice, semi-portable "handheld".

As of right now, I have three options:

A) Use a small heatsink and REALLY short duty-cycles
B) Use a huge heatsink and longer duty-cycles.
C) Use a 50W TEC to regulate the temperature on the TEC (and have the other side of the TEC connected to a the base metal of the structure - will provide adequate heatsinking).

I like the idea of using a TEC. It would provide a lot more stability. However, the issue is, what's the best way to attach the bar to the TEC? Just thermally glue it on?

What's the best way to drive that TEC, anyway? Should I just make sure it doesn't drop below 40 F or so and just adjust the current going to it until I get a stable temperature?

Thanks for the advise, all

 

[justinjja]

Adding a Tec to a 40W hand held would make it overheat worse (Is option C even a handheld?)

Not sure how much you know about Tec's but to cool a device that puts out 50W of heat
You need a tec with a Qmax rating of at least 50W (Most tec's FS on ebay lie about their Qmax rating, or don’t give it at all)
something like a 40mmX40mm 12V 6A would work,
However you now have to cool the 90W of energy that the tec uses + the 50W of heat your laser puts out,
or 140W of heat that has to be dissipated on the hot side of the tec


Why not make a hand held with a fan in it?
I'm pretty sure I saw one of those recently...

 

[Wolfman29]

Very true.

By all means, this is not going to be a typical "laser torch." Rather, the idea is to make it strap to my wrist or something and have more of an iron man like laser - something that I can flip on and cut with, etc. I am probably going to have about a pound or so of copper on which the driver (50A D: ) and the array will sit on.

Of course, this will still be powered by 18650s (2s2p, I am thinking).

 

[justinjja]

Sounds like something I want to see a video of when finished
What kind of a driver will it use?

 

[Wolfman29]

It'll probably be a long project... but it'll happen. So far, the driver is pretty small - only a 2.5 inches on each side (single-sided to provide the best heatsinking possible for the huge power dissipation =p

 

[RyanElectro]

This sounds very cool straight up and sounds like this is going to be a really awesome gagdet. Ironman heat blast.... haha

A suggestion: why don't you look into some micro fans for your cooling (low speed for low noise)? I have been thinking about doing a build with a microfan for some time but don't have the money for r&d. . I think you'll definitely be able to engineer it into your gauntlet-type build. A piezoelectric fan might have some use for you as well :beer:

 

[Wolfman29]

Actually, I have a few microfans lying around... actually have a project planned to incorporate one into a build! But I hadn't thought of a fan here! But I will need something bigger than a microfan =p I'll probably need to go normal size.

 

[Bionic-Badger]

Could you using something like the heatsink + fans that cooled the laser projector laser arrays? They should've been able to remove at least 40W of power. Maybe you could use some water-cooling? There are some small rigs for video cards, and having those tubes coming from your laser wrist attachment would look pretty cool.

 

[Wolfman29]

Hmmm... will consider it as well.

 

[RyanElectro]

Yeah water cooling would be some crazy stuff, really look like iron man then.

Only thing is.. you need a radiator, and that's not going to fit on an arm lol.

 

[cilegray]

Computer CPU heatsinks can easily handle upwards of 100W with an adequate fan... and that's inside a cable-cluttered case. I'd look into those

 

[AUS]

Tec drawing heat into Water cooling with Backpack heat exchange and fan? lol

You'll make more noise than my Argon

 

[TheReddish]

I would not use a tec, or water cooling, you are going to need a heatsink to displace 50w right, well a tec may putt of 80w extra to deal with on the hot side(just a guess to lazy for math) a water cooler needs a pump and their is more heat gererated. a small top down cpu cooler, that comes with a 125w cpu can handle at max fan speed more than 120w, now you cannot mount it like you would on a cpu, so it will not work as good, but you should be able to get into the 50w range no issue. I have a big mugen 2 in 3000rp push pull running full heat prime 95 and battlefield 3 and civ 5 at the same time, my heat-sink never gets more than a bit warm on the furthest point. Cpu collers are one thing, but a gpu cooler has to displace 250w of heat on a high end card.

 

[Hiemal]

Get some sizeable KTP crystals while you're at it; make a 10 watt green laser.

Of course, water cooling seems like it'd be best. You'd need a backpack, regardless though. There's no way you're going to be able to get 40 amp draw from 18650's and have them last any amount of time.... Bigger batteries are needed.

 

[Wolfman29]

Well, Mr. Quack, the 18650s can handle up to 30A draw regularly > I figure with 2p2s I will be drawing approximately 15.6A in order to power my PSU. That's 7.8A from each battery. So I figure that, assuming they each have a capacity of 2AH, then I can probably get about 10 minutes out of each charge, which would be more than enough for me.

And no. I won't need a backpack >

 

[Wolfman29]

But there is one problem (I just realized). How the HELL am I going to measure the output current of the driver? =p