Awakened by the heat of my LSH-S left on.....

A heart warming tale about an LSH-S light.........

Last night, I had turned on my LSH-S light to admire it's beam, and must have dozed off. For some reason I woke up, found it in my hand, still on and almost too hot to hold. I am sure that this is what awakened me. So I turned it off, removed it from the down-filled blanket, placed it on a book to "simmer down", and checked the blanket to see if it had been marred or burned. It had not!

I am sure that the super heat while in my hand awakened me, since the light in the room was still on and I would not have seen the LSH's beam because of this. I didn't have the brains to look at the clock to see what time it was, even though it wouldn't have made any difference since I didn't know when I fell asleep.

So I have had my first experience with my first ARC light providing some additional warmth to the steam heat that I get. How long is it supposed to take, before the thermal protection circuit turns it off? I measured the voltage of the battery unloaded and it was 2.97V. I am sure that I knocked the wind out of it, and will have to get another CR123 battery armed, and ready for active duty..... I will be more careful from now on.

Sorry , no thermal protection circuit in the LSH only Arc4 have (and need) that !

The heat output of Arcs must really vary from light to light. I've had my LSH-P on for 25+ minutes and as long as you're holding it, it's hard to tell that it's gotten warm at all. If you sit it on a countertop where almost nothing's touching it, you can tell that it's warmer than when you put it down, but it's still not very hot.

The LSH does have thermal protection but it is set at a higher point thant the Arc4. The setting is for ~150f at the sensor but the sensor is further away from the LED slug than the Arc4. When reached, the LSH will shut the LED off but continue to draw some power so you want to turn it off and let it cool down.

Peter

I think the Premium models have a lower Vf / more efficient LED than the Standards. On the charts I've seen, their runtime is longer indicating they consume less power. This would result in cooler temperatures.

And this means that the LED will experience higher than 150 degrees F, before the cutoff occurs? At what point will the LED experience non-recoverable heat induced damage? Or have you made this an impossibility?

Can you estimate how much life is left in the CR123 battery, if my voltmeter reads 2.97V unloaded? You must have done some runtime tests, using voltage under load as one of the parameters. You must have generated some charts, showing the increase in runtime with the decline in battery voltage. If you could share this chart with me, I could determine how much juice is left in the battery, either before regulation ends or the light output is deemed unusable.

By the way, what is the measured lumen output drop right after the end of regulation, and for how long is this sustained? The light starts out at 15 lumens, and is rated to last 2 hours with a CR123 battery. What is the first recorded lumen level just after regulation ends? What would you consider to be the lowest usable lumen level?

Luxlover, we do not have such test data for the LSH or the CR123 cell. Sorry.

Peter

About a handful of times in the past I became aware of my LSH-S accidentally activating in my pocket by the intense burning sensation I would start feeling on my leg. /ubbthreads/images/graemlins/mad.gif

luxlover, u may want to reference this thread re battery test :
http://www.candlepowerforums.com/ubbthreads/showflat.php?Cat=&Number=505511&page=2&view=collapsed&sb=5&o=365&fpart=1

Just out of curiosity, how much current does an LSH (S or P) draw from the battery? I took some quick measurements on my LSH-S:

CR123: 0.373 amp at 2.67 volt (0.99 watt, mostly dead cell)
CR123: 0.458 amp at 3.30 volt (1.51 watt, fresh cell)
NiMH : 0.497 amp at 2.52 volt (1.25 watt)
Alka : 0.488 amp at 2.91 volt (1.42 watt)

Last Thanksgiving I left my ARC LSH-P turned on in my pants pocket and was suddenly aware of a burning sensation in my groin - I immediately reached into my pocket and pulled out the light - if I remember, it was flashing on and off and was quite HOT! When the high temp cutout activates does it cause the LED to pulse to protect it from additional heat??