Streamlight TL-3: Clever design addresses issues

[brightnorm]

Re: Streamlight TL-3: Clever design addresses issu

[ QUOTE ]
McGizmo said:
BrightNorm,

I haven't seen the TL-3 but I do have a TL-2 (impressive light in its own right). If the TL-3 is designed similar to the TL-2 I question some apparent possible contradictions in your comments on thermal management??

"Clever design yields excellent heat control. Bezel contains reflector and unique floating, shock-isolated LED assembly. Very thick aluminum head functions as effective heatsink, aided by slim but long body. One piece head/body."

Now I am confused how the module can be shock isolated and yet thermally connected? The TL-2 has a LED module that makes a hard and forced contact with the battery tube at one end and the reflector at the other but essentially floats within the head. Is this also how the TL-3 is designed?

Now here is a quote that I find rather interesting:

"....because rapid heat buildup in the KL4 and McModule makes sustained tests impractical..."


Ultimate steady state temperature of the light will show how effective it is in passing the heat off in convection and radiant forms. I agree that the TL-3 having more surface area should have a lower steady state temperature than the other lights. However since you have stated that the KL4 and McModule have rapid heat buildup, I think you have inadvertently identified these lights as having superior thermal management over the TL-3 if I may suggest that removal of heat from the LED qualifies as superior; not hand hold ability. I can make you a Titanium flashlight with a thermally isolated battery tube that will take forever to get warm. By the time it reaches steady state, the poor LED will be sweating bullets.

- Don



[/ QUOTE ]

Don,

Because of my non-technical background I may use inexact terminology. I'll answer your questions as best I can.

Now I am confused how the module can be shock isolated and yet thermally connected? The TL-2 has a LED module that makes a hard and forced contact with the battery tube at one end and the reflector at the other but essentially floats within the head. Is this also how the TL-3 is designed?

Exactly, it is relatively isolated from shock because it "floats" on that spring assembly


Now here is a quote that I find rather interesting:

"....because rapid heat buildup in the KL4 and McModule makes sustained tests impractical..."

Ultimate steady state temperature of the light will show how effective it is in passing the heat off in convection and radiant forms. I agree that the TL-3 having more surface area should have a lower steady state temperature than the other lights. However since you have stated that the KL4 and McModule have rapid heat buildup, I think you have inadvertently identified these lights as having superior thermal management over the TL-3 if I may suggest that removal of heat from the LED qualifies as superior; not hand hold ability. I can make you a Titanium flashlight with a thermally isolated battery tube that will take forever to get warm. By the time it reaches steady state, the poor LED will be sweating bullets.

The difference here is that I am functionally orientated to the user, rather than to the way heat disipation cools the LED. It has always seemed ironic to this layman that the more efficiently a light thermally protects its LED, the less hold-friendly it becomes, as long as you are trying to keep the light as small as possible.

I wonder if there is a solution to this problem. Would very efficient LEDs be a partial answer? For instance a 300 lumen 5 watt LED producing 60 lumens per watt, and run at 1 or 2 watts. Would that allow it to run "cooler"?

There are times when I wish I had an engineering background, but my poor math skills make that impractical.

Thanks for your input Don, I always learn from you.

Brightnorm

 

[McGizmo]

Re: Streamlight TL-3: Clever design addresses issu

BrightNorm,

I didn't mean to come down on you and certainly not having a TL-3 to look at, I made assumptions and interpretations. I think it is a safe bet that the brighter the LED is relatively speaking (higher luminous output) bin the less heat it produces but this efficiency increase somewhat pales to the over all inefficiency of the LED's at present. Certainly the best thing, in my opinion, for LED lights is to provide optimal thermal paths to the body and heads of the lights. If a light gets too hot in use, there is no false sense of security here; the LED is getting hot as well. The Luxeons are current dependent and any resistored or DD approach will effect one LED considerably different than the next unless the circuit is designed or considered with a specific LED in mind with tested Vf and current resulting from various likely levels of Vin.

I think the best method of relieving thermal "pain" to the user is to under drive the Luxeon. This was really driven home to me with a mod I did using one of ArcManias micro converters and placing a Luxeon in a tiny Head on an Arc AAA. I know I had a good thermal path as the LED was adhered to an integral bulkhead of the small head. At about 160 mA of current to the LED, the head did not get hot, even after 15 minutes of running.

For people who need to walk around with a light constant on for long periods of time, I think they need to consider LED's driven at or below spec as well as larger hosts which do have the mass and surface area required for lower steady state temperatures. I believe that most SureFires as well as probably the StreamLight units have been designed with more tactical applications in mind where a constant on use is not prevalant; or at least that's my impression.

The 5W Luxeons coupled with good reflectors are really impressing us these days and the amount of light output is simply amazing. Realistically though, do we *need* this much light in an endeavor that requires the light to be on for 20 or 30 minutes continuously? Maybe some do. I know I don't. If I want to leave a light on that long, it is likely for task work or maybe walking around and in both cases, a 1W is more than sufficient for my needs. Wayne Y. and I have both made PM6's with 1W R2's driven at 400 mA. These lights can out throw the 5W's if focused tight and they can provide a very acceptable wider beam for mid range illumination. These lights require between a third and a fourth of the thermal relief of the 5W's. The PM6 body and size can easily handle this. I have also modded a KL4 with one of the R2 1W's and it is a great light that doesn't heat up like it did in its former configuration.

We can deny or hide from the physics but we can't change it. If you want a long run time 5W light that's thermally *honest*, it won't be pocket size. Unless of course the 5W is underdriven.

Peter Gransee's plan with variable output as well as some of the other variable output lights we have been seeing or expecting will offer another solution to the size VS brightness equation.

I believe I am mostly correct in what I have stated but please consider it to be from a layman's perspective and understanding.

Ramble [off]

- Don

 

[JohnK]

Re: Streamlight TL-3: Clever design addresses issu

Just spent an hour with my new TL-3 LED, comparing with a 6P, 4AA Propolymer, Surge, SL 3AA one watt Lux, Twin-Task 3C, and a 9P, all with fresh batteries. It is REALLY dark here in Tennessee now.....

This TL-3 LED is a real HOSS !!! The tighter (not much) beam of the 6P, and 9P, were brighter at the "spot" than the TL, but the FLOOD of nice white light, with tremendous side spill (I have not seen this before) really blew me away. This is one USEFUL, and bright light.

We try to "measure" Lumens; I'm an optometrist, recently retired, and have spent a good part of my life really getting into this stuff. Anyone that can say that he/she "measured" Lumens, or relative brightness, is not full of horse hocky, but simply, it is just impossible with our redimentary measuring instruments (and eyeballs). I was struck with the tremendous differences in beam color, spread, spill, and all the nuisances that make visible light so indiscribable.

I used to use a "candlepower" instrument in some industrial work; it impressed the clients, but, after a bit, not me.

I guess we'll have to rely on our good old subjective quality judgements most of the time.

My old eyes like this TL-3 LED, with it's combination of flood, spot, long run time, and great feel, quality, and price. The second choice of my many lights is my 3C Twin-Task for the same reasons.

Aren't we having fun ? Enjoy..............

 

[AilSnail]

Re: Streamlight TL-3: Clever design addresses issu

As the LED heats up, its efficiency goes down. A light with a bad thermal path will thus have a higher steady state temperature on the outside than a light that conducts the heat away from the LED.
Also, the hotter led has a lower voltage requirement for a given current. This means that it will consume more power from the batteries if it is direct driven. The batteries get more efficient when they get warm (to about 60C?), thus adding more power.

It is possible to design a light that convects heat to the air while not conducting to the body. An example of this is metal fins with an insulating edge.

Sigurd

 

[brightnorm]

Re: Streamlight TL-3: Clever design addresses issu

[ QUOTE ]
McGizmo said:
BrightNorm,

I didn't mean to come down on you and certainly not having a TL-3 to look at, I made assumptions and interpretations...For people who need to walk around with a light constant on for long periods of time, I think they need to consider LED's driven at or below spec
...Realistically though, do we *need* this much light in an endeavor that requires the light to be on for 20 or 30 minutes continuously? Maybe some do. I know I don't...
Peter Gransee's plan with variable output as well as some of the other variable output lights we have been seeing or expecting will offer another solution to the size VS brightness equation....I believe I am mostly correct in what I have stated but please consider it to be from a layman's perspective and understanding.

Ramble [off]

- Don

[/ QUOTE ]

Don,

I never felt dumped on, and I don't even see any real disagreement, or at least everything you said made sense to me.

I generally use 1 watters for walking, and brighter lights for "spotting", but there's a Flashmaniacal side of me that wants a tiny superbright light that never gets hot and burns forever!

I think variable lights are a great idea, and I'm looking forward to the next ARC.

Don, if what you're saying is from a layman's persp[ective where the h@ll does that leave me! /ubbthreads/images/graemlins/smile.gif

Brightnorm

 

[SilverFox]

Re: Streamlight TL-3: Clever design addresses issu

Hello Brightnorm,

I guess you are just a well informed flashoholic.

Tom

 

[Gransee]

Re: Streamlight TL-3: Clever design addresses issu

Don's on the money guys. A DD or Resistored LED light that is bright and compact should be hot to the touch if the LED has a good path to the housing. On the flip side, the smaller the housing and the less fins, etc the hotter it will be for a given heat load.

I contend that fins pale in effect compared to a nice big hand wrapped around the metal body. So you could say that for a given hand, the light that feels hotter is either brighter or better heat conductive. For comparison, look at the LSH. It can get quite hot in about 10 minutes and it is underdriving the LED. It also has a better run time than other single 123 flashlights so you know that heat is not coming from an increased inefficeincy but an increased heat conduction. I understand the SF L4 gets even hotter and has a shorter run time.

A lot of lights coming out now days are tuned more for brief usage and less for long tasks.

Another issue I am sure we could debate is the effect of heat damage on real output and LED life. Will you notice it? Do you really want to risk it? I have seen a certain light (won't say the brand) that overheats a bunch of 5mm nichias. This light is known for individual LEDs winking out suddenly.

Personally, within limits, you won't notice a difference in life. For me, it is more an issue of efficiency. This affects densisty and is seen in brightness and run time. These are factors that you are much more likely to notice.

Peter

 

[brightnorm]

Re: Streamlight TL-3: Clever design addresses issu

[ QUOTE ]
Gransee said:
... For comparison, look at the LSH. It can get quite hot in about 10 minutes and it is underdriving the LED. It also has a better run time than other single 123 flashlights so you know that heat is not coming from an increased inefficeincy but an increased heat conduction... Peter

[/ QUOTE ]

This is why I EDC the LSH-P with 2AA tube. With lithiums I can count on about 5hrs regulated. The closest any other very small 1Watter comes to this is the 3x123 UBH/KL1 which gives 6 hrs reg but is significantly bigger ande heavier.

Your variable lights are going to be VERY useful.

Brightnorm

 

[MR Bulk]

Re: Streamlight TL-3: Clever design addresses issu

Sounds like a good candidate for resistor REMOVAL -- direct drive, and with a nicely sized reflector to boot!

Given the much earlier ship date, I can only presume that "beautiful circuit" was never incepted in production.

 

[BuddTX]

Re: Streamlight TL-3: Clever design addresses issu

[ QUOTE ]
MR Bulk said:
Sounds like a good candidate for resistor REMOVAL -- direct drive, and with a nicely sized reflector to boot!

Given the much earlier ship date, I can only presume that "beautiful circuit" was never incepted in production.

[/ QUOTE ]

Charlie,

Nextr time you talk to your Streamlight Sources, can you find out what happened? I was so looking forward to a mainstream light that had regulation, not just a resistor.

 

[Free]

Re: Streamlight TL-3: Clever design addresses issu

If anyone wants mine to try a mod on, let me know. I just got it and I am very dissapointed. It is not quite as bright as my L4 and has a similar color to the beam. The beam is also not as clean as the L4. The brightness just does not seem right for this size of light with 3 cells in it. I am getting spoiled by my Hyperlux /ubbthreads/images/graemlins/smile.gif

 

[JohnK]

Re: Streamlight TL-3: Clever design addresses issu

Mr Bulk You're the man on these things. If one of you gifted individuals think the TL-3 LED would be OK without resistors, I'd love for someone to tell me how to do it.

The LED module looks like it is not designed to take apart.

???

 

[brightnorm]

Re: Streamlight TL-3: Clever design addresses issu

[ QUOTE ]
JohnK said:
Mr Bulk You're the man on these things. If one of you gifted individuals think the TL-3 LED would be OK without resistors, I'd love for someone to tell me how to do it.



[/ QUOTE ]

But then we'd come full circle around to a very bright, hot and short burning light with rapidly declining brightness. Why not regulate the TL-3 at very high Mah to get, say 15 or 20 minutes of intense brightness?

Unless you plan on using your TL-3 in true tactical burst mode, in which case an unresistored superbright would probably be OK, you might have a more satisfying result using the other approach, assuming that it would be technically feasible.

Brightnorm

 

[McGizmo]

Re: Streamlight TL-3: Clever design addresses issu

Brightnorm,

You would *hope* hot in DD. I say this as a result once again of assuming a similar build to the Tl-2. I suspect that StreamLight has resistored these lights for conservative current levels and it is likely that the thermal issues are satisfactory, if not stellar. From what I can gather, one would want to start from scratch with a different Al module that should be thermally joined, at least with AS grease to the battery tube, if one was contemplating DD.

- Don

 

[Free]

Re: Streamlight TL-3: Clever design addresses issu

There is no way this thing is 90 lumens as they claim.

 

[brightnorm]

Re: Streamlight TL-3: Clever design addresses issu

[ QUOTE ]
McGizmo said:
Brightnorm,

You would *hope* hot in DD. I say this as a result once again of assuming a similar build to the Tl-2. I suspect that StreamLight has resistored these lights for conservative current levels and it is likely that the thermal issues are satisfactory, if not stellar. From what I can gather, one would want to start from scratch with a different Al module that should be thermally joined, at least with AS grease to the battery tube, if one was contemplating DD.

- Don

[/ QUOTE ]

Don,

I reread all your comments and realized that my use of "thermal management" was inaccurate, and I've edited my review accordingly.

Thanks,
Brightnorm

 

[AilSnail]

Re: Streamlight TL-3: Clever design addresses issu

[ QUOTE ]
I contend that fins pale in effect compared to a nice big hand wrapped around the metal body.

[/ QUOTE ] I think you're right. The fins could come in handy other places than the grip, and if an unfinned grip would get too hot to touch.