Any fan cooled bodies for SST-50/90 yet?

[space-time]

I'm wondering if anyone has made a flashlight body with a fan in it yet for SST-50/90 use? More specifically, something like a small turbine blower exactly the size of a 18650 or 26500 that would replace one battery, sucking air in the ends of the blower from slots in the flashlight body rear and head (cooling the batteries and emitter in the process) and then out slots machined in the side of the tube? Such a thing could tap off V+ by passing the battery V+ through as end posts on the blower, then a wiper on the (anodized removed) inside tube wall for V-. Maybe groves would be needed on the inside surface of the tube to mate with slots on the turbine blower, to keep reaction force from rotating it in the tube.

I'm drooling over Der Wichtel's 9 amp SST-90 driver. But if the body of whatever I put it in gets too hot to hold after 10 minutes - or even if I just can't run it continuously until the batteries are out - then the utility just isn't there for me.

Example: on Olight's website I just read the following posted right now about the SST-50 M31: "Warning: Please use high mode sparingly. Due to its high power consumption, an excessive amount 0f heat may be built up and it may harm the batteries and the flashlight." Doesn't sound terribly useful other than a showpiece, on high mode. If I'm buying a light with a "high" setting, I want to be able to run it continuously on high!

Seems like the usefulness of passive cooling (fins and surface radiation) for flashlight bodies is nearing the end with these new SST-50 and SST-90 emitters - and whatever comes next. Active cooling (fans) is going to be needed to get the heat out. Although running a small blower fan will reduce battery life, it is kind of a moot point if I can only run the light 10 minutes anyway before it overheats with a SST-50 or 90. If the fans gets me 20 minutes that is a 200% improvement in usefulness, in my book.

I'm old enough to remember how x286 and x386 PC CPUs did just fine with nothing more than a heat sink and no fan. Now it would be unthinkable to run a CPU without fan forced cooling (or liquid cooling) of some kind due to modern high CPU wattage output.

Thoughts? Anybody create a fan-flashlight body yet? I did a forum search for "fan", "fans", and "fan cooling" before posting which all turned up zip. If there is already a thread about this, please point me to it.

 

[bitslice]

Like you pointed out, the current tubular form factor of a hand held torch isn't ideal for any kind of active cooling.
The in-line turbine idea is novel, :thumbsup: getting a miniature fan in there is certainly possible but sadly I can't see it pushing much air around a tightly packed tube.

Computer cooling techniques are very applicable to the spotlight form factor though, replace the lead acid battery with a LiPo and there would be a lot of room for a water pump.

Personally I'm really hoping to see people engineering in a series of heat pipes into their designs, the conventional torch shape would remain, but the heat buildup around the LED would be reduced - especially if fan assisted radiators were added at the rear.
The current trend for massive slugs of copper is convenient given the constraints, but still a bit crude maybe

I'd love to start making these ideas but I don't have a lathe or a milling machine :sigh:

 

[ma_sha1]

There was a Triple p7 mag done with fans, can find the link

 

[bitslice]

There was a Triple p7 mag done with fans, can find the link

made by sabrewolf I believe and bought by TheGreyEminence

sabrewolf was also talking about heatpipes back in 2008

I'll edit in the P7 link if I can find it


edit:

got it
http://www.candlepowerforums.com/vb/showthread.php?t=208585



I'll link his solution to removing the heat from the led,
the fan blows out through holes drilling in the head section

 

[IMSabbel]

One problem with fans is that they get much more inefficient with shrinking size, so a 20mm fan that would fit behind a poll would be loud and unreliable.

One thing I noticed a few weeks ago but have yet to try are those things:
http://www.led-tech.de/de/High-Powe...SynJet®-PAR38-LED-Cooler-LT-1697_106_114.html

They use some kind of vibrating membrane coupled with microjets as a fan.

edit:
http://www.led-tech.de/de/High-Powe.../SynJet®-MR16-LED-Cooler-LT-1696_106_114.html
this one was the one i had in mind. 50.5 mm diameter is a bit more managable than the one above.

 

[bitslice]

thanks for the link, that's pretty neat, I've heard of it for laptop cooling but I hadn't seen it implemented yet

One problem with fans is that they get much more inefficient with shrinking size, so a 20mm fan that would fit behind a poll would be loud and unreliable.

True, but there is no reason why a properly spec'ed 20-30mm fan would be unreliable. A 30 mm fan would have the same dB rating as the microjet concept.
A crossflow fan would probably generate a higher flowrate than an axial fan, if one could be engineered to fit

I still find it unusual that some level of fan assisted cooling is almost unheard of, even for exotic custom designs.
Why add masses of copper when a fan will easily halve that requirement?

edit:
http://www.led-tech.de/de/High-Power-Zubehoer/Kuehlkoerper/SynJet%C2%AE-MR16-LED-Cooler-LT-1696_106_114.html
this one was the one i had in mind. 50.5 mm diameter is a bit more manageable than the one above.

ah, now that looks interesting at 19euros and 120 grams, maybe not for a really high power torch at 15W but an interesting high tech solution for (I'm guessing here) a P7 ?

Anyone out there fancy using this in their next design ?


(OK, I'll admit it, I'm bored of seeing people retrofit maglites all the time )

 

[space-time]

Good thoughts! Thanks for the link about that Mag light with the fan in the head. I hadn't found that thread. I like the heatpipe ideas too. That is a fairly mature technology now for laptops, as far as I know. If nothing else heatpipes could be used to move the emitter heat out to a better location on the flashlight for a fan on fins.

Here is the concept:

Just shrink the motor and blower cage inside down by 95% and stuff it into the barrel of a flashlight. I have 4 of these blowers from Sam's Club and I'm just amazed at the amount of air they put out vs. a conventional fan. It would sure be interesting to see what a turbine blower could do for air movement in a flashlight.

From the datasheet graphs of semiconductor heat sinks a fairly small amount of air velocity past the heat sink, vs. just static air, makes a fairly large difference in heat transfer. Even if miniturization of the blower cuts most of the efficiency, which it probably will, the result may still be enough to make a difference.

That pulsed air flow device from the German company is interesting. Here is something fun to do: copy and paste that entire link for the product into a Google search box

http://www.led-tech.de/de/High-Powe...SynJet®-PAR38-LED-Cooler-LT-1697_106_114.html

then do the Google search, then hit the "translate this page" that comes up with the search. Does a near perfect translation from the German.

One likely side effect of anything rotating at a high speed in the fan body: a gyro effect when moving the flashlight around. :green: Maybe two counter-rotating blowers end to end would be a better idea than one long one.

 

[MikeAusC]

Hi Spacetime

Im building a Searchlight Spot to Floodlight using SST-90 cooled by Heatpipe.

Because I want to have a wide range of beams types and light sizes, I'm taking a modular approach using PVC plumbing fittings to house the optics - up to 140mm dia 500mm focal length lens !

This my first ever use of a Heatpipe heatsink.

The Heatsink I used is a "Zerotherm Atom 30H" - it was on special under $30 from iibuy.com.au because no-one uses low powered CPUs anymore (<120watt !!!). It's a two-tube CPU cooler rated up to 60 watts. It's only 100 x 85 mm.

The LED mounts on a copper block 30x30x5 and I'm amazed how cool the LED stays even with no fan running.

I'm working frantically to get it ready for a Search Exercise we have on this weekend with the Police, so I won't be posting any photos till next week.

 

[bitslice]

--------then hit the "translate this page"

just click the British flag at the top of the page, they've already written the page in both languages :thumbsup:

 

[space-time]

MikeAusC: What a good idea - using an existing CPU cooler with the base / heatpipes / fan and just mount the LED where the CPU would go. That hadn't even occured to me. I'll bet that does work very well. The wattage rating is even in the ballpark. You've found a complete SST-90 heat sinking solution in-a-box! :thumbsup:

Well with your efforts and the light Walterk posted, it is looking like spotlights are going to take the lead on fan cooling. So over the next few years maybe people will slowly work on shrinking things and the technology will eventually make its way into flashlights.

Maybe the form factor we are all so used to for flashlights will need to change a bit to accomodate fan cooling. Maybe the head will need another 3/4 inch of depth or so behind the LED to accomodate a miniture version of a cooler just like yours, then holes bored on the side of the head (like that light pictured earlier in the thread) to let the air out as it passes through the fan.

Another side benefit to the fan cooling should be more light output! No more de-rating of the LED's lumens after the first minute or so due to heating. Good cooling should allow for full power all the time.

bitslice: sure enough, I see that link now. Good to know! Thanks.