Has anyone ever made a flashlight that uses a fan?

[Cavelightchris]

I know how people are always using CPU heat sinks in their designs, but I was wondering if anyone ever hooked up a tiny fan to their heatsinked flashlight?

Now I know you wouldn't ever use even the smallest one at Radioshack since it uses .13A / 130 MA, but I was wondering if anyone knows of a super tiny, and super efficient fan?


I was wondering, what happens if you squeeze a bunch of LEDs in one tiny light to where all of the LEDs are touching each other, is this a bad idea, could this be a good enough excuse to maybe run a fan in it?

Ok I'll admit it, i just want it to have a fan for bragging rights "ya I made this flashlight, it even has a fan in it" lol

Well if anyone knows anything about using fans in flashlights, as inefficient as the idea is, could you still please drop me a link or tell me about it, cause I am dying to hear about something like that.

That would be great if I could find a tiny fan that would last for 12 - 100 hours on a single double A. I would even spend a $1 at radio shack for a battery pack if I could find a fan like that.

Someone must have some knowledge on tiny efficient fans, and their cost, I'm on a thin budget for mass production purposes.

 

[Marduke]

Might have better luck with superior conductance to the heatsink, such as

http://www.sciencedaily.com/releases/2006/05/060502171803.htm

 

[frenzee]

I've used the ADDA AD1505 and AD1506 series, albeit not in a flashlight. Mouser carries the ADDA line but they don't always have them in stock. The 1506 is only 15mmX15mmX6.5mm so it's really small and sounds like a tiny jet when it winds up. It only uses 40mA and it makes a HUGE difference in cooling when compared to ambient air cooling. As you can see here, I am driving five Lux IIIs at 1A using a shaved AD1505 and a relatively speaking small heatsink.

 

[Krit]

I had ever use mini cooling fan from computer display card. It's not hot after long time operate but I think that it's not realy commom use.

 

[TorchBoy]

Chris, with your caving-theme handle you might be interested in a plan I have for a caving headlight, using a 40mm 5V fan at just under $3 each. Actually, it's more of an idea than a plan at this stage, but I have the fans, and they work quite well. They even have blue LEDs! My brother has even started using one to cool a graphics processor heatsink in his computer.

I don't think you're going to get much cooling from a fan that lasts a dozen hours on an AA. Edit: The AD1506 fan frenzee mentioned above might, but you'd need a boost driver for a single AA or 3-4 AAs to run it, and the closest fans Mouser has are bigger, and in the $18-22 range.

 

[nein166]

http://www.candlepowerforums.com/vb/showthread.php?t=158356

Glockboy put this masterpiece together from scratch note the fan and heatsink.

 

[jeffosborne]

My 6-rebel Hydra Torch uses a fan, it only comes on when the thermistor mounted to the heatsink reaches 150 degrees: http://www.candlepowerforums.com/vb/showthread.php?t=170249 It is a 12v 80ma unit. My latest build uses a 5v 40ma ADA fan from Future Electronics: D040-06P05 Jeff O.

 

[frenzee]

Yes, the ADDA fans are defnitely not cheap (approx. $20) and they come in 5V and 12V flavors I believe so you will need a boost circuit to drive them from 1 or 2AAs.

 

[Cavelightchris]

Thank you everyone for the info, I would love to make a person flashlight that used one of those, but I am working on one for mass production so I am on a tight budget.

---------------------

Caving Heatsink Idea:

I realized that caves are always so cold that you might as well take advantage of this rather than using a fan anyways.

This is what I came up with, you use a real big heatsink, drill a hole through the flashlights side and through the heatsink and out through the other side. Next you stick a thin pole through it, or one with a heat sink design like featured in the picture below. Then for waterproofing; spotweld both sides:

I might use this design for my own version, but it will never see production.

So does anyone know where or if you can buy a pipe like that, one that if you look through it, looks like it has heatsinks which are as long as the pipe?

 

[tanawah]

I have done a few mod jobs, but so far only passive cooling. I would look at the tiny motors used in some cheap remote control cars with a home made fan blade. Basically it costs a predictable amount of power for every cfm of air that you circulate. A physically small motor will most likely be quite efficient and will not impede the air flow. Computer fans are not very efficient as they do not use rare earth magnets. You are best to use efficient heat sink fins such as copper sheet to reduce the need for massive air flows.
Next problem is how to get the air in and out without making the light useless because it is not sealed.

 

[nein166]

Thank you everyone for the info, I would love to make a person flashlight that used one of those, but I am working on one for mass production so I am on a tight budget.

---------------------

Caving Heatsink Idea:

I realized that caves are always so cold that you might as well take advantage of this rather than using a fan anyways.

This is what I came up with, you use a real big heatsink, drill a hole through the flashlights side and through the heatsink and out through the other side. Next you stick a thin pole through it, or one with a heat sink design like featured in the picture below. Then for waterproofing; spotweld both sides:

I might use this design for my own version, but it will never see production.

So does anyone know where or if you can buy a pipe like that, one that if you look through it, looks like it has heatsinks which are as long as the pipe?

Ok Chris your pipe idea is interesting but the surface area is not enough. Radiating heat out into the air is all about surface area. If used in a cave around 15 C any multipin computer heatsink made of aluminum would take out more heat than an LED can generate unless your using an OSTAR that LED will be cool

Look into a good copper heatsink and you wouldnt need a fan. These heatsinks are designed to dissapate 50Watts and higher

The Princeton tec apex headlamp has a heatsink exposed to air and wrapped in a silicone rubber cage. Air flows through and gets the 3 watts out.

Good Luck on this build.

 

[Sgt. LED]

Pipes like that can be made, think of hammering rifling into gun barrels. As for not enough surface area, make the "pipe" a sealed unit filled with some type of liquid coolant.

 

[TorchBoy]

Yeah, I was going to mention rifling. I don't imagine the pipe will be very useful because you would have to get a convection thing happening through it for it to take any heat away.

Perhaps I should mention that my planned caving headlamp will only use the fan when on high mode, which might be as many as four Crees running at 1 amp each (total about 14.4W). On normal mode, I imagine the passive heatsinking would be enough.

Do I understand the thermal resistance of a heatsink correctly? The heatsink I'll use has a thermal resistance of 5°C/W. Does that mean its temperature will rise over ambient by 5°C for every watt of power its dissipating? So in dissipating 14.4W of heat it'll rise 72°C, or hit 87°C in a 15°C cave. I wouldn't need to bother with a fan if that's the case.