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Clockwork
10-11-2008, 08:57 PM
With a lot of talk recently about Multi-die LEDs and their heat creating potential, I have been looking into the engineering behind active cooling (IE. fans). I just found this website that I thought I would share, as it was a huge help for me working out my equations.

http://www.electronics-cooling.com/articles/1996/may/may96_01.php

Hope it helps

Count Malik
10-12-2008, 10:52 AM
Cool but it all depends on how big it is.:cool: Like would it fit in a hilt or would you have to take the electronics out to cool 'em:grin: But still cool indeed!

Clockwork
10-12-2008, 11:25 AM
Cool but it all depends on how big it is.

I take it by 'it' in this statement you are referring to a fan yes? Depending on the heat generated, and the temperature you want to keep the LED at. If you don't want the LED to increase in temperature and it generates heat, you need more airflow, if you don't mind in increasing by a few degrees and it doesn't generate as much heat then you need less airflow. One can easily find fans that will fit in a hilt, Mouser has a wide range of them. If you need a bigger fan for your application, either: you need to generate less heat, or, allow your LED to heat up more, or make a custom hilt that can incorporate a bigger fan.

So long as one can work out how much airflow they need (which you can thanks to the website), one can look at these high power LEDs realistically and work out if fan cooling is a viable option for one's project. (I am pretty confident that the calculations have worked in the project I am working on, and will post results when I have a chance to test them).

tinfoilhelmet
10-13-2008, 09:18 AM
holes in hilt to supply air to heatsink works pretty good. i don't know if my putting holes in the lensholder made a difference but i did so as well. i got a lux3 running on 2 amps heh.

Kant Lavar
10-13-2008, 11:33 AM
Hm...

Here's a wild idea - a protosaber that, on the belt, includes a small liquid cooling pump setup. (I know it's not practical from a power standpoint, but it would look badass. Especially on a steampunk saber with some major flicker in the blade... :cool:)

Clockwork
10-13-2008, 01:02 PM
Hm...

Here's a wild idea - a protosaber that, on the belt, includes a small liquid cooling pump setup. (I know it's not practical from a power standpoint, but it would look badass. Especially on a steampunk saber with some major flicker in the blade... :cool:)

As an experimental project that would be pretty interesting. Not only could you store the cooling pump, but also large batteries to power even the highest power LED.

Realistically, however, I think that liquid cooling is ridiculous. There is no need to go that far in a saber, my car doesn't even have a water-cooled engine (71 Volkswagen Beetle). Remember a liquid cooled system still requires something to cool the water, the liquid is only used to transfer heat to a cooling device (like a radiator), not do the actual cooling. Might as well just mount a fan directly to the heatsink.

Kal El Rah
10-13-2008, 01:02 PM
There are systems for PC's that use liquid cooling setups with the parts required to cool the heatsink to the CPU, not very expensive and use antifreeze as the heat transfer medium(GREEN,ORANGE). This might be something You guys might be interested in. Sorry I don't have any links but I am sure they are still out there. With a light source for the clear tubing would look really kewl and can drop the temp over 50% on overdriven or high heat LED's.

vadeblade
10-15-2008, 01:33 PM
Cool but it all depends on how big it is.:cool: Like would it fit in a hilt or would you have to take the electronics out to cool 'em:grin: But still cool indeed!


http://i258.photobucket.com/albums/hh258/vvvv_767/fansmall3.jpg
Made by Sunon... :D

swear000
10-15-2008, 02:38 PM
tiny! computers in the future will be as big as a Rubik's cube!

Ari-Jaq Xulden
10-15-2008, 03:13 PM
i believe this (http://www.evercool.com.tw/products/nanofan.htm) one will work as well in a mhs. in fact they have one that is 22m also

Angelus Lupus
10-15-2008, 03:47 PM
Gotta love the Engrish on that site:


Enjoy the multimedia and beautiful your life.

Clockwork
10-15-2008, 04:54 PM
i believe this (http://www.evercool.com.tw/products/nanofan.htm) one will work as well in a mhs. in fact they have one that is 22m also

Yeah this fan is actually quite a good example, it is spec'd for up to 1 CFM which is quite good for the size, the best I was able to find was .6 CFM. I will be receiving the .6 model fans soon and will post results.

Angelus Lupus
10-15-2008, 05:11 PM
Forgive me for asking this, but.. unless you have large enough holes in the saber you're not going to be able to pull cool air in or push hot air out, are you?:confused:

Clockwork
10-15-2008, 05:32 PM
Depends on a couple of things, one is how much pressure your fan can deal with. The saber I am working on does have a large portion of grill to deal with the airflow. Again, I am not suggesting that fans will work in all sabers, it is possible it may only work in sabers with reasonably sized air holes. Still, it opens up the option for people willing to incorporate holes in their design.

Novastar
10-15-2008, 11:25 PM
Forgive me for asking this, but.. unless you have large enough holes in the saber you're not going to be able to pull cool air in or push hot air out, are you?:confused:This is a good question, Angelus. In fact, it stands to reason that why would it not be better to use the ENTIRE HILT (in some form, with some plan/design) in order to channel the heat versus trying the fan thing.

Either way, going back to the fan thing with airflow... you're right to some extent that without a source of "new" air coming into the saber... it'd be awfully weird to expect the fan to do much. Granted... just pulling the massive heat away from the source is SOMEthing. :)

Still... with a sort of "swiss-cheese"/cheese-grater hole setup near the heatsink and fan--moving the saber around with swings and dueling would (surprisingly) create some good airflow!

Problems are...

* Not tested
* Demonstrating the saber for too long WITHOUT swinging it around wildly = fried LED? Too much heat? Reduced light? All of the above?
* The "normal" air may not be enough--even with good airflow--to cool the heatsink... depending on the LED, power, etc.
* Requires a __VERY__ specific setup that is not conducive to just any ol' setup and any ol' LED and heatsink.

I'm sure there are more issues, but... I have always wanted to test something like this. You know... some kind of UBER-BRIGHT saber that forsakes all the goodies for brightness + fan + heatsink... and if it fails, oh well, chalk up to EXP. :)

Jouster
10-16-2008, 11:58 PM
Novastar:

I would have to say that NOT swinging the saber around could be bad without a fan: I believe constant airflow is very important.

Also, the rate of airflow may even be critical for some highly overdriven setups.

Everyone:

I'll use an example to demonstrate my points (now bear with me that this may not be the best example!):

I fly electric RC aircraft that are made out of foam. In one case, I mistakenly kept an airplane's electronics from being cooled properly (no cooling ports were made in the receiver/battery compartment). Now, this particular plane was running at about 18 amps, and put out somewhere around 150 to 200 watts of power. Needless to say, after just a two minute flight, the electronics got very hot. I then cut just 2 cooling holes, both around 1/2" in diameter, and flew the plane again. Though the cooling ports weren't overly large, the difference was HUGE: my electronics were merely warm after a 10-minute flight.

Now, mind you, this is an extreme example when related to what we are doing here, but it certainly seems that constant airflow is key in order to manage heat, and that regular air can do the trick. (At least, if the saber is properly set up for good airflow.)

EDIT:

Whoops. My bad on that one. Novastar, I had misinterpreted part of your post; for some reason, I had thought that you had suggested to just allow for airflow (holes in the hilt, ect. ) and NOT have a fan in addition to this. Again, by bad.

I used Lithium Polymer batteries in that aircraft: a 1500 mAh, 11.1 volt (3 cell) setup. I was merely using this plane in order to demonstrate the cooling efficiency of mere airflow, without the need for water cooling and all that. And, no offense intended at all, but I did say that this was an extreme example :) What I was thinking of was a heavily finned heatsink for the LED, and a fan pushing air right past these fins and out through a bunch of small ports that would surround the heatsink. I think this might be enough.

Novastar
10-17-2008, 12:25 AM
Jouster... regarding what you said about swinging the saber around to create airflow--that's exactly what I was saying. It almost sounded as if you thought we disagreed. I was saying YES, it would likely be needed to have heatsink + airflow (cheese grater holes or whatever) + swinging to cool certain specific (extreme) LED setups... such as those resulting in say 10w or more of heat as example.

But I disagree about your model plane analogy--and only for the reason that LED sabers simply do not need ANYWHERE near 10A (or even 5A) at present... and certainly not 5A consistently. I've heard of some (recently!) that will draw 3A and maybe even 4A... but not really consistently... and this would make up 1% of LED sabers, probably less.

I'm guessing that you used NiMh for your model plane setup... and I do not know how "hard" someone can suck energy from those cells (differs with brands/makers I guess too), but Eandori has told me quite a bit!! I guess that's a lotta heat! :D

Anyhow... I think these alternate and fun experiments with heatsinking for sabers is a great idea! Small fans (maybe more than one, I don't know)... heatpiping configurations that perhaps utilize the entire hilt in a more sophisticated heat situation... even water/coolant systems!!

I mean... sure, everyone will balk at first, but... it's the same thing everyone told me when I said I was going to make some live SW battles on stage. Same thing when I said I was going to make super-inexpensive (but neat lookin') CF props when v1.2 first showed up! :) Probably same thing they told Tim when he started the saber shop!

"Duuuuhhh, whatever Tim--yer NEVER gonna make money sellin' geeky saber parts!! That's GAAAAAAY!"

Hmm... they be EATEN some words NOW, hhuuuuuhhhhh!!! :D :mrgreen:

DACOTA
10-17-2008, 06:00 AM
Amen.

Onli-Won Kanomi
10-17-2008, 10:33 AM
Maybe Obi-Wan was on to something with that thin neck and vane section...maybe someone could make it so that section was an ACTUAL fan to cool the hilt down and force air in through small holes in the thin neck and grenade section if using extra-hot LEDs?

tinfoilhelmet
10-17-2008, 08:31 PM
the rectangular holes in the mpp or heiland work very well for airflow 'round a heatsink...and led emitter area hence holes in lens holder. a fan would be a bonus, but i'm still using my x2 overdriven cyan lux111 as a reading lamp with no fan.

TroyO
10-27-2008, 12:51 PM
Hehe... my first thought is to get a tiny fan.... then cut off one of the blades. Now you have a fan AND a vibration motor... ;-P

(Seriously... for our purposes a pager motor with a tape "Flap" that spins might be enough.)

Novastar
11-23-2008, 08:08 PM
Leia: Would it help if I got out and pushed?!?
(Pause. Han slowly glares at Leia.)
Han: It might.

:)

All good ideas, guys! :) It seems to me that "faster, more intense" (heheh) heatsinking/cooling is definitely going to be needed as LEDs get more nutty with Transylvanian bloodthirst for voltage and/or current.