L4 Temp Measure

Measure Point: Distinct gap between the tail threaded portion and the middle reflector body
Equipment: Fluke 179

Min C F
0 26.1 79.3
5 39.4 103.7
10 45.5 114.1
15 47.9 118.5
20 50.8 123.4
25 53.1 127.0
30 54.7 131.4
35 55.3 131.8
40 56.6 133.5
45 57.3 135.2
50 57.8 135.8
55 58.1 136.6
60 58.7 137.8
65 59.6 139.4
70 59.9 139.8
71 60.0 139.0 (flash once)
75 60.1 140.0
80 61.2 142.0
85 62.8 144.8
90 59.3 137.7
95 53.1 127.3
100 47.8 117.6
105 43.5 110.6

End of session. At this point, my L1 is brighter than the L4.

Thanks. That's good info. While many of us have light meters, I think few are equipped to measure temperature.

Cool. (hum.. I mean hot!) /ubbthreads/images/graemlins/thumbsup.gif

Thanks for the info.

Nice table!

At what point is something considered too hot to touch [for more than a couple seconds]?

I heard that 140 deg F is the Max Average our skin and nerves will tolerate.

how much is that in Celsius?
bernhard

140F is about 60C.

[ QUOTE ]
kiessling said:
how much is that in Celsius?
bernhard

[/ QUOTE ]

60 degrees celsius... au, that's hot. And indeed it's getting real hot that monster.
/ubbthreads/images/graemlins/grin.gif

converter

Edit:
to slow... /ubbthreads/images/graemlins/wink.gif

thanx guys!
when I finally have mine, I'll do the test and hold it firmly in the hand for at least 30 minutes and we'll see if the human liquid cooling system can provide some help to the poor KL4 ...
bernhard

Very good point kiessling. If someone is holding the light their body will be acting like a cars radiator, maybe desmondpun can run a second test while holding the light /ubbthreads/images/graemlins/smile.gif

well, if he dares doing it, I hope for the sake of his hands that this fine theory has at least some practical relevance. /ubbthreads/images/graemlins/grin.gif
might considder using his left hand ...
bernhard

I did touch the L4 body during tht test. I don't think I feel too comfortable to hold L4 after 20-25 minutes of running.

No, don't pick it up during the test - start off by holding it. The temp shouldn't get as high, and you'll probably be OK, if not a big uncomfortable. I held mine for ten minutes, and it wasn't bad, actually. Held it by the head and switched hands a couple of times. Still, I think I'll let somebody else try this test first. Mr. Science is on vacation. /ubbthreads/images/graemlins/smile.gif

since mine has not arrived yet, another one will have to be the first to try ...
/ubbthreads/images/graemlins/grin.gif
bernhard

Well, I just did a run time test for a Panasonic CGR17670 Li-ion (one hour and seven minutes, btw) in my L4 and held it for the full hour. As some of you suspected, the "liquid cooling" effect kept the temperature down to a comfortable level.

It did get warm, but never what I would term "hot" (i.e. unpleasant to touch.)

Cheers,
Bob

In doing runtime tests, the bezel cap of my L4 has gotten as hot as 161 F. The body stays about 20 degrees cooler. This is not comfortable to hold onto in my experience. The temperature was measured with a Raytek "MiniTemp" infrared thermometer. The light was sitting on a tiled countertop in 80 F ambient air.

I seem to average about 60 minutes of regulated light with the 17670 Li-ion cells. I've seen it range from 55 to 72 minutes with a sample of 3 different KL4s.


Peter

Yep - that seems to be what I'm getting. About one hour on the nose for continuous run time. I'm curious to see if the runtime might be slightly longer with intermittent use (e.g. 5 on/5 off) but I'm not focused enough to find out.

I didn't point out in my earlier post that I was holding the bezel in my hand during the run test, not the body. As long as I kept it in contact with my skin, the temperature stayed in the "comfortably warm" range, but I didn't actually measure it.

Cheers,
Bob