Raw NS emitter / safe high runtime

[paxxus]

I just did a ceiling bounce test using a cheap lux-meter in a small white room. When I compare against my Ra 100 (which I trust is calibrated to output 100 lumens) my Raw NS seems to output around 190 lumes

Back when I ordered my Raw NS only the 160 lumes version was available, so my question is if the recently shipped Raw NS' (mine shipped Jul 22) in fact have the latest R2 emitter in them? Is there anyway to tell what I got (my emitter is silver colored around the die, but I don't know if that indicates anything)?

Second question. I notice that the heat sinking in the Raw NS is close to non-existent. The emitter ring couples fairly well to the reflector but I'm not sure how well the emitter die couples to that ring, in any case the reflector is only indirectly in contact with the body via the glass window (the reflector doesn't screw in).

Given the impressive output on high combined with my observation on heat sinking I'm worried that I might damage the emitter if I have it on high too long.

So, what is the maximum time you can have the Raw NS on high without risking damage to the emitter?

Thanks.

 

[orb]

The heat sinking on the Raw series is efficient. That is the reason the outer body becomes warm on high after say 5 mins continuous.
There used to be much more caution to preserve the life of the LED. & we would recommend not much longer than say 5 mins on high whilst holding in your hand.
You will find that your hand acts very well to conduct heat away from the torch/LED.
With some time now gone by running LED's fairly hard in a small package & no failures to report there is less concern on how effected the LED is.
Still No doubt the hotter the LED is run for longer periods will reduce the life of the LED.
Due to the relatively short run time achievable in the Raw series on high 200, & the actual amount of use I see no reason for concern.
Another reality fact is with the continuos rapid improvement in efficiency people like to upgrade there LED to the latest greatest.
At the moment the Cree R2's are pulling about 550Ma & providing 200 Lumens
In the day of the Luxeon the LED would pull 1000Ma + for about 80 Lumens...
Over the last few years the improvements in efficiency of the LED's has really benefited the smallest lights. Some reports are showing 260 Lumens with the latest R2 Cree's!

Your Raw NS has the R2 & run time on high is really what you feel comfortable with.
If you prefer we do offer the other lumen options. The 100 High & 20 Low is ample light for most tasks, there is virtually no heat & run times up to 1 hour.
Its just impressive to have 200 Lumens in a package smaller than your thumb. :thumbsup:

 

[paxxus]

Rob, thanks for your thorough reply - I'm much less worried now, especially since experience shows that my concern is groundless.

Yes, having access to 200 lumens in such a little package is truly something to behold. Very glad I got the R2 emitter!

 

[Erasmus]

I just finished my Raw NS with Cree R2/WG and this thing really screams, incredible to see what comes out of such a small light. Thanks to Rob @ Lummi!

 

[zipplet]

I've used my Raw NS 100/20 on high for roughly an hour and the light just got warm in my hand, kinda like using a Fenix on turbo. I'd say the heatsinking is pretty good and it's safe

The Wee NS does get pretty warm as it's a tiny light, even at 50 lumens.

 

[Erasmus]

I actually made some extra heatsinking on my emitter, I'll upload some pics later. It's made of a solid copper wire which is bended to make a copper disc.

 

[paxxus]

I actually made some extra heatsinking on my emitter, I'll upload some pics later. It's made of a solid copper wire which is bended to make a copper disc.

Yes please do.

The reason for my original concern is that the conductive heat path from the emitter to the body is either:

1) Side ways through the PCB (isolating by virtue) to body.
2) Through reflector (reflector has air gap to body) to glass (isolating) to body.
3) Through PCB to battery through battery spring to body.
4) Air.

So you see, unless you count PCB, glass or air as an "efficient" heat path, the emitter seems to be quite isolated. I would think that a screwed in reflector would help tremendously towards dissipating heat from the emitter to the body and as an added benefit the o-ring could be squeezed harder thus improving water resistance.

Anyway, the proof is in the pudding as they say, so if this has not been a problem in practical use I'm happy. This post was just to give a little more info about my original concerns.

 

[Jay R]

1) Side ways through the PCB (isolating by virtue) to body

And down through the PCB into the top of the bottom half of the case. The 'switch' part if you like. The PCB is quite dense and when switched on high quite a lot of it touches the case.

 

[Erasmus]

Here is a picture of the heatsink I made on my Raw NS light engine :

It's a solid copper wire bended into a spiral so you get some kind of a flat copper disc. It is soldered to the PCB's thermal path, the LED's thermal path, the ground, and the 2 through-hole via's on the PCB. Then I soldered the + of the LED to the + of the PCB.

Advantages :
- safe to run from full battery to empty battery in high mode
- heat is directly conducted to the flashlight's body in high mode
- heat is not conducted anymore through the PCB material, which has a pretty high thermal resistance

Disadvantage :
- I had to sand down the reflector by a bit since the LED is now sitting 1.5mm higher.

All in all I like the modification, I did not measure the exact temp of the body but I feel it gets much warmer than without the modification, which is a sign that more heat is drawn away. My hands are pretty heat-resistant so for me it never gets too hot, my body is a good heatsink for the torch

/off and heading to the cheers&jeers section