Any runtime updates for the L2 on high beam?

[luxlover]

Has any new owner of the SureFire L2, done runtime tests in high beam? The results of the first two tests done by Craig of The LED Museum, were not indicative of SureFire's lights that are regulated. I would like to consider the L2, but I need some more runtime input. The 40-50 minutes that Craig clocked, is not good enough for me, considering that the L4 and L5, both using 5 watt Luxeons and two 123 batteries, have been clocked for 55-60 minutes.

 

[taylor]

See Run-Time Plots by kj at http://www.candlepowerforums.com/ubbthreads/showflat.php?Cat=&Number=487560&page=0&view=collapsed&sb=5&o=&fpart=1

and the runtime plot from Japanese website: http://www.flashlight-fan.com/flame_page/frame_l2.htm

 

[Gandalf]

Well it's not too surprising to see that SureFire is continuing to turn out vastly overpriced, poorly performing
Luxeon lights. Hey, get the L2: costs more, less run time! Get two! /ubbthreads/images/graemlins/banghead.gif /ubbthreads/images/graemlins/thumbsdown.gif

Or just buy an Inova X0 at *less than* 1/3 the price and get an excellent white beam, and great run time. So it's not a SureFire; the point is: IT WORKS!

 

[Kiessling]

do I sense some negative vibration here /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/evilgrin07.gif /ubbthreads/images/graemlins/wink2.gif ??
bernhard

 

[luxlover]

"Yes".........and "no!" Don't worry, though, it's strictly "harmonic!" Unless the L2 is improved STAT (a famous medical term!!!) SureFire's reputation will have a small scar... They better boogie fast and fix it, before the problem increases "exponentially!"

 

[Kiessling]

Has anybody done output measurements of the L2? Or are there some stats officially announced?
Maybe it is just brighter than the L4 and that is why it has a shorter runtime?
bernhard

 

[Mister T]

Maybe you should have had a look at the runtime plots first. http://www.obaq.tv/cpf/images/SureFire_L2_L4_Runtime.png

 

[Kiessling]

I had that look, and I looked before posting.
This is runtime data, and not light output comparison. lux is not lumens.
bernhard

 

[Mister T]

[ QUOTE ]
Kiessling said:
lux is not lumens.

[/ QUOTE ]
Sure, but both, the L4 and L2, use the same reflector and a 5W Luxeon, don't they? Assuming that the distance between light and luxmeter was the same I don't see a problem in comparing the brightness of these two lights. /ubbthreads/images/graemlins/rolleyes.gif

 

[luxlover]

I love it! Two German flashaholics, "regurgitating their thoughts" here in front of us. Wunderbar!

Bernhard has a point. What if the L2's high beam output is greater than the L4's 65 lumens? Has anybody measured it's output in lux or better yet in the terms we can use to compare the two.......lumens? Bernhard, wouldn't lumens be a better term in this case, since we would like to compare the two head to head?

Mister T, maybe Paul Kim "tweaked" the L2's high beam regulation circuit, to bring out more output than what was used with the same 5 watt Luxeon in the L4? This is a possibility! It would solve this mystery if Mister T's idea of measuring their lux levels was implemented. While we are at it, how about we find a $15,000 integrating sphere for the lumens measurement! Who has these devices? Speak up!

Remember that Luxeons are getting better.... whiter, brighter, and cooler running. Bernhard's point is good. Who is going to find this out for us? This would explain a shorter runtime! With regard to the graph here http://www.obaq.tv/cpf/images/SureFire_L2_L4_Runtime.png, notice that the L2's lux intensity descends to and intersects that of the L4 (~790 lux) at 34 minutes, and continues to descend rapidly. If the regulation circuit was identical in both lights, then their curves would be parallel in their descent out of regulation. Any thoughts?

 

[Kiessling]

I do not know if they use the same reflector, but they do use different drivers for sure. And how should we know that the little difference in lux shown in the runtime graph will not produce some not-so-neglectable difference in lumens, meaning a higher drive current and less runtime?

I always see a problem when light output is estimated by looking at runtime charts. Too much unknown variables:

- beam spread / reflector
- luxeon-lottery of the units used
- variations in LED placement in reflector (--> donut hole)
- etc.

bernhard

 

[luxlover]

All good points again, Bernhard. What do we do, if we are trying to decide on the L2 based on runtime, when all we have at our disposal is a chart showing lux levels and runtime?

So when will you be buying an L2, and investigate all these variables for the rest of "the gang?"

SureFire, or one of our loyal reviewers/evaluators, must give us more data about the L2, since at this time not enough is known to compare it to it's closest relative the L4.

 

[Kiessling]

/ubbthreads/images/graemlins/grin.gif
Jeff, I won't buy the L2, I'll use Don's McE2S on my L4 /ubbthreads/images/graemlins/evilgrin07.gif
IMHO there's not much to do than to wait for some experts to chime in or for SF to publish results of their integrating sphere ...
bernhard

 

[Mister T]

[ QUOTE ]
luxlover said:
SureFire, or one of our loyal reviewers/evaluators, must give us more data about the L2, since at this time not enough is known to compare it to it's closest relative the L4.

[/ QUOTE ]
How true... But have you noticed the huge difference in Lux in the flashlight-fan charts?
L2 high beam
L4
Apparently, the L2 registers 700 lux in the beginning, the L4 only 450. You can see this difference in the beamshots as well. More confusion coming up. Terrific! /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/tongue.gif

 

[McGizmo]

Since the L2 is a two stage light, I would expect it to have a higher drive current on the high level than the KL4. I would certainly expect a higher drive current to translate into a reduced run time as well. Given the variations in flux from LED to LED I personally get more useful information from the level of drive current in anticipating what to expect from a comparison of one light to another, ceterus paribus. The 5W LED's in use today have shown to be at diminishing returns of light output at current levels at or above the the factory spec. This is not to saythat more efficient LED's of tomorrow won't be more efficient at these same current levels and provide a greater return of light. We certainly have seen in the Lux III over the 1W a greater yield of light output at higher and even over driven levels of current.

Speaking only for myself and my useage of lights, I find the L2 to be a significant improvement over the L4 because of the regulated low level of output where the LED's efficiency is greater and good useable light is available for extended periods of time. Since I use the "top end" less than the low end, I would want the top end maxed at light output; runtime and efficiency be damned.

If I *ever* read a certain CPF member's post where he claims that a SF is priced in keeping with other manufacturers lights, I will suspect either a mistake has been made or SF has made a light that is compromised in materials, design or features to meet a price point instead of being the best it possibly can given current technology, components available and design goals.

 

[luxlover]

Whoa! Is the McE2S that super dynamic, fantabulous, dual mode switch, that drops down the L4's 65 lumens, to save battery juice? That is a brilliant idea. Come to think of it, you have been brilliant all morning! (in your case it is afternoon!)
Did you have a good breakfast and lunch to make your brain work so well?

We can only hope that SF will do us this favor....before the turn of the century!

 

[luxlover]

Yes I have seen the charts. Irrational behavior......

We are starting a real revolution here. Are you listening Mr. SureFire? Help us out, please!

 

[kj]

Just FYI, to my eyes...

[*]Beam pattern - L2 and L4 are identical or very similar.
[*]Brightness - Almost same on the high mode.

My L4 is not mod'ed. I don't know my L4 is exceptionally bright because this is only L4 I have.

 

[McGizmo]

luxlover,

If it weren't for the switch on the L1, A2 and now L2, I never would have come up with the McE2S. I have also found in the last couple months when I have built lights planning on incorporating this switch, that I have gone to higher levels of output for the "high" since this is not the only *speed* that the light will be used at. In fact, realistically, with variable output, I think most folks when really using these lights will be using the low level most of the time and the high level will be the occasional "overdrive" so go ahead and set it at a level of overdrive. I am not sure I am explaining my thoughts properly here. /ubbthreads/images/graemlins/icon3.gif

I do seem to now have in my posession a reasonably intact driver from a L2 so I will fire it up on the bench and measure the current to the LED in high mode. As I recall, the KL4 is somewhere in the low to mid 600's (mA). If, as I expect, the L2 is closer to 700 mA, a reduction in run time would be expected and the performance of these L2's as some of the graphs are now showing, will be explained. I am guessing that as the effecacy(sp) of the 5W's improves, the L2 platform will come into its own and be appreciated that much more.

 

[357]

I'd like to eventually see runtime at the low level.

Personally, I don't plan on using the high level much, why shorten the life of the Luxeon in situations when you don't even need 60 lumens? After experimenting with my L2s, I find that the 15 Lumen setting is ideal for 99.9% of my needs. If it will run 3-4 hours at that level, I am happy.