Just a reminder... These flashlights can get hot!

Just a reminder, these flashlights can get hot. Especially if they are left on and unattended. Certainly do not leave them with kids, they can get hot enough to burn their tender skin.

We are not the first company to make a pocket flashlight that gets hot, nor is ours the warmest but, I just wanted to remind you guys to be carefull with these flashlights.

This applies to the LS only. The Arc-AAA is unlikely to ever get that hot. But the Arc-AAA is small enough to be choked on. Even an adult could choke on it if they were carrying it in their mouth.

It would make me quite sad if anyone was ever hurt by one of my flashlights. Please be carefull!

Peter Gransee

This is why we all love Arc, Peter, and his flashlights. A lot of company's look only at the bottom line. It's nice to find a company who cares about honesty, integrity, and their customers so much.

Me thinks someone may have just read about the Brit who burned a particular sensitive spot with his laptop?????

Seriously though..thanks for the heads up PG..
sometimes folks can forget these babies can get cooking !!

[No message]

Peter,

Don't forget this one:

WARNING - MAY CAUSE EYE DAMAGE OR TEMPORARY OR PERMANANT BLINDNESS IF THE FLASHLIGHT IS TURNED ON AND POINTED DIRECTLY AT THE EYE.

WARNING - MAY CAUSE SEVERE PAIN IF SHOVED DIRECTLY INTO THE EAR, NOSE, THROAT OR ANY OTHER BODY ORFIACE.

Originally posted by lemlux:
The lawyers, the courts, and you members of the jury have forced McDonald's to serve tepid coffee to save McDonald's shareholders from opportunistic litigious old biddies who pour coffee on themselves.

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<font size="2" face="Verdana, Arial">People often use this example but this was actually a pretty interesting case.
The woman suffered full thickness burns (or third-degree burns) over 6 percent of her body.
She was hospitalized for eight days, during which time she underwent skin grafting and debridement treatments.
She originally sought to settle her claim for only $20,000, the cost of her medical payments.
It was only after McDonalds refused that a jury got involved.
The McDonalds coffee which was served at 180-190 degrees is now served at 155 degrees -- hardly tepid.
Home brewed coffee is on the average of 135-140 degrees.

I carry my ARC LS in a pocket. I do worry that it might turn on without my noticing. It's usually obvious if the LS starts blasting a hole through my clothes but not my winter coat. If it sits for any length of time in all of that insulation it could be quite a problem. The LS really ought to have a positive lock-out of some kind for this reason.

I assume heat is the ultimate limit on using 5W LEDs in an LS body – even if you could tolerate the run-time it would be too hot to hold with so little surface area to radiate from.

PS. I'm having a nightmare of an LS with one of those tiny notebook computer fans mounted behind the LED...

GJW:

I don't dispute that the lady in question suffered significant scalding. I do strongly feel that what she or anyone does with his or her coffee, intentionally or unintentionally, in his or her own car should not impose any legal liability exposure to the coffee vendors.

When I buy coffee I like it hot. I can allow it to cool down to taste in whatever vessel from which I choose to drink. When traveling, I frequently transfer fast-food coffee to an insulated travel mug or thermos to keep it hot longer. Not only is it difficult to reheat coffee on the road, but reheated coffee loses flavor.

I would hate to see restaurants stop serving plates of fajitas pulled straight from the oven that bubble and sizzle in the cooking / serving vessel because I might put my hand on the plate or spill it on my lap. That day, alas, may come.

I drink a lot of tea. I pour 212 degree water into a cup or pot before I steep the tea. I frequently preheat the cup or pot to make sure it's as close to 212 degrees as possible. That's 32 to 42 degrees warmer than McDonald's "socially irresponsible coffee."

I do not appreciate a legal system that continues to find ways of protecting me from myself by transferring the financial consequences of my potentially inept use of a product to the people who sell me things. The end result is that my effective freedom of choice continues to be incrementally constrained.

Dont forget this warning:
WARNING: CARRYING FLASHLIGHT IN FRONT POCKET THEN FALLING DOWN ON LIGHT, MAY CAUSE SERIOUS DAMAGE AND PAIN TO THE MALE GENITAL AREA.

Oh, I know! Let's have all flashlights, particularly ones that can fit in a pocket, declared to be weapons by law, and require Concealed Carry Permits in order to even begin the process of buying one!

My wife looked up the McCoffee case. The reason the jury awarded the lady so much was that it came out in the trial that McDonalds management knew the coffee was dangerous but had made the financial decision that it would be cheaper to pay off injured customers than to fix the problem.

Originally posted by BuddTX:
Dont forget this warning:
WARNING: CARRYING FLASHLIGHT IN FRONT POCKET THEN FALLING DOWN ON LIGHT, MAY CAUSE SERIOUS DAMAGE AND PAIN TO THE MALE GENITAL AREA.

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<font size="2" face="Verdana, Arial">that is the funniest thing i ever heard!!!
oops i fell
D'oh

mike

We need koozie Arc LS holders.

hell ya we do!

May have to start wearing a "cup" when "carrying"!

Technical Questions for the technoids here:

Since the heat produced by a properly operating Arc LS-X is waste heat, an undesired output resulting from the ineffeciencies of converting electrical energy to light, I have some questions:

1) Does anyone have any idea of the relative efficiencies of the typical Arc LS (a .4A hybrid, for example) and an "equivalent" (Ha!) incandescent flashlight?

2) What are the primary sources of the heat produced by the typical Arc LS?

Side note: I actually expected the NiMH cells I use in place of the single 123 to be a significant contributor to the overall heat output due to the fairly high load placed on them. This turned out not to be the case as the cells themselves remained quite cool while I was testing their endurance in powering my Arc LS Hybrid. It would appear that the heat load is therefore from the electronics and emitter. This leads me to my third question:

3) Are any advances expected in the near future that would make the conversion more efficient?

(The Energy Conversion Efficiency of a typical lightbulb is about 5%, or in other words approximately 95% of the electrical energy applied to a bulb to produce light produces heat instead, which is wasted energy in this case. A 100% efficient device for converting electrical energy to visible light would produce no heat.*)



Thanks!


* This makes the obvious assumption that "visible light" does not include infrared, which is not visible . . .

T

i disagree with that table at least one point in that table.

there is nothing in the world that is 100% efficient.

some is lost in resistance...some in sound...some in light...a heater or a hair dryer are most certainly not 100% efficient.

i don't think really that using rechargables will effect the heat of your ls, because of the electronics used, they will automatically convert the neccessary energy required to run the led.

If there's really so much "waste heat" being produced, you should try to do something useful with it. Instead of mounting a heat sink directly to your LED base, sandwich a thermoelectric module in there first, and the heat sink after that. See this paper for an example circuit design:

http://www.ece.uvic.ca/~jbornema/Journals/064a-97ia-jmd.pdf

Originally posted by Rothrandir:
i disagree with that table at least one point in that table.

there is nothing in the world that is 100% efficient.

some is lost in resistance...some in sound...some in light...a heater or a hair dryer are most certainly not 100% efficient.

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<font size="2" face="Verdana, Arial">Think about it - an electric heater is designed to convert electricity into heat. When you look at efficiency losses in a circuit, where does the lost energy go? It turns into heat. What happens to the energy in a sound wave or light after it is absorbed by an object? It turns into heat. As such, 100% of the energy fed into an electric heater got converted into what you wanted.

Sean,
Good idea on the ARC koozie... I would be in for a few.