High power LED flashlights and integral thermal protection

What high power (Luxeon 1W or higher) flashlights commonly used offers active overheat protection?

[Add: quick summary of test result]
Tests I conducted:
Minimag 2AA LED: body temp stopped climbing at 51°C

River Rock K2 headlamp: appears to lack protection. Plastic parts melted, heatsink reached 170°C

Streamlight 4AA Luxeon's LED module: stabilized at 82°C measured at interior of the integral aluminum reflector. Module is kept inside the body and it is not direclty exposed to the user. Tested with 5.1v regulated power supply and blankets covering the module: Stabilized at 82°C

Other's result:
Fenix L2T by The_LED_museum reported entire body became too hot to touch and his IR thermometer reported 68°C, which is higher than the boiling point of methanol and hot enough to cause a burn to the user.

Full size Mag LED 2D: Newbie's graph in threads shows the module, which is covered from direct access from the user while in use stabilized at around 72°C

All these tests were of course, at room temperature. A flashlight should be able to handle usage in every one of their modes at any reasonably encoutered environmental condition without safety hazards or self-damage.



Original thread:
The Mag LED series definitely have a thermal protection and the output is reduced considerably as the temperature of the heatsink reaches a certain point.

Streamlight's ProPolymer 4AA Luxeon seems to have a similar protection with the output dropping slightly and the heatsink temperature stays steady once it reaches a point.

RiverRock K2 offers no protection at all and it allows the LED to reach a temperature in excess of 170°C (at heatsink, higher in the chip).

Anyone know if the Fenix and other aluminum 2AA flashlights offer thermal protection in foreseeable undesirable conditions, such as being activated inside a jacket pocket? If a L2D was to be turned on at full power in blankets, would the temperature be limited below what could cause a permanent damage to itself or start a fire?


Edit: RiverRock has no protection, which was able to reach 170°C at heatsink under good insulation with 3 NiMH batteries.

My result:


Mag 2AA LED: good insulation and NiMH batteries caused the body temperature to stabilize at 51°C.

Streamlight 4AA Luxeon: Input current and output are slightly reduced after the few minutes, but heatsink temperature remains steady. This suggests active thermal protection.

Others' result:
Newbie's test showed MagLED powered by 2C cells climbs up to 72°C in the first ten minutes of use as the light output declined steadily.
https://www.candlepowerforums.com/threads/119665&page=1&pp=30

Handlobraesing said:

...Anyone know if the Fenix and other aluminum 2AA flashlights offer thermal protection in foreseeable undesirable conditions, such as being activated inside a jacket pocket? If a L2D was to be turned on at full power in blankets, would the temperature be limited below what could cause a permanent damage to itself or start a fire?

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Sounds like a test LED_Museum would run. "In the name of science" of course.

this is off topic but can an led create enough heat to ignite common household materials?
i like the thermistor idea mag uses, keeps the led alive. how long at what temp is too much for the crees? i accidentally fed a cree 6v and it drew 2 amps. it glowed for a second after i removed the power. dont think it did much damage but hard to tell by output alone.

The early Fenix series for sure don't have thermal protection. I don't believe the latest series has it either.

I know for sure the Arc4 series and all HDS lights have it.

The Night-Ops Gladius/Insight H2X offers thermal protection.

Here's my Minimag 2AA LED under test, which is putting it under conditions much tougher than it would reasonably see.

It's inside a sealed bottle, which is under 100% Freon atmosphere with 60% less conductivity than air and the whole setup is placed in a plastic cup to reduce conduction loss at the bottom. It is then, covered with a blanket.

It is setup with a freshly charged Rayovac hybrid and it would be allowed to run for at least three hours.

Who wants to test their L2T or L2D under the same conditions?

You just aren't going to give up on your anti-Fenix thing are you?

I tested my Fenix 2,30m under water, no leak, no water insight and the light worked well.
I guess, your Minimag would get wet inside

This was a real world test. I'm not intended to cover my light with a blanket, because it will surely not to be cold.
But if I would do it, I'm sure it would survive.

My light is better than yours :lolsign:

Best regards

____
Tom

Long John said:

I tested my Fenix 2,30m under water, no leak, no water insight and the light worked well.
I guess, your Minimag would get wet inside

This was a real world test. I'm not intended to cover my light with a blanket, because it will surely not to be cold.
But if I would do it, I'm sure it would survive.

My light is better than yours :lolsign:

Best regards

____
Tom

Click to expand...

Would you say the accidental activation of your light in your pocket, luggage, backpack is not a reasonably foreseen misuage?

chevrofreak said:

You just aren't going to give up on your anti-Fenix thing are you?

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What I said isn't biased. I merely suggested someone to conduct the test.
This has nothing to do with anything Fenix. It was mentioned since it's a very common light here and it was the melt down of my headlamp that made me want to test my other ones.

I have a fenix L0D-CE and it certainly does not have thermal protection (aside from the fact that the batteries will only run it on high for about 12 minutes). I usually only use tghe lower levels, and only use high with it in my hand to conduct the heat away. A L0D-CE that was designed to use 10440 would be ideal IMO -- drawing a steady 600mA (as opposed to 1A) in "max" mode, along with thermal feedback would be downright cool. At 600mA, the LED will be almost as bright as it is (due to diminishing returns) yet, the battery life would last a lot longer. Thermal feedback would be a must though in my opinion were they to release such a light as most casual users probably aren't willing to be as cautious as me (though most casual users probably won't have 10440s to begin with...).

Handlobraesing said:

Would you say the accidental activation of your light in your pocket, luggage, backpack is not a reasonably foreseen misuage?

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For me, no.

If it turns on in my pants pocket, I will feel the heat. This happened to me once in all my years of carrying lights and I figured it out in less time than I often run a light. If I'm going to stick it in a pack or luggage, I'll remove the batteries or back the tailcap off enough to prevent activation. I have never had a light turn on in a pack.

Maaaaybe I could be carrying it in an outer jacket pocket and not be able to feel the heat. In this case, I'm not sure how it could be activated in the first place, and I also don't see that much insulation would be offered in this case.

Any way you cut it, I don't see how hard it is to prevent this kind of thing from happening. I won't throw a light into a pack loose with batteries in it, just like I won't toss a loaded handgun loose into a pack. Nor do I toss electronics loose into a pack without engaging the 'lock' feature. Expensive tools require care and attention.

Am I saying that thermal protection wouldn't be nice on a light? If it can be offered at only a negligible cost increase, I might consider it a nice feature in a light, but I don't care enough to seek it out. I don't consider it a design flaw if it's lacking. I also would hate to have a light back off power on me trying to be too safe.

Throwing a light into a pack in a way that it can turn on may be 'safe' with a light that is thermally protected, but when you go to retrieve it the batteries might still be dead. Doesn't seem very responsible.

TOTC said:

For me, no.

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I'm not asking how it would apply to you in specific. Using your reasonable judgment, would you say it is reasonably foreseen that the light will be accidentally activated in storage or put in pocket while turned on and forgotten about?

Why do microwave ovens have interlocked door instead of cautioning user to "do not open while in use or activate before closing door" ?

Let's see, there's a chance you'll get shot at while driving, but a car is not built with bullet proofing without a special order, because it is not really foreseen.

There is a beam in each door, because it is reasonably foreseen that you maybe invovled in a side impact accident.

Throwing a light into a pack in a way that it can turn on may be 'safe' with a light that is thermally protected, but when you go to retrieve it the batteries might still be dead. Doesn't seem very responsible.

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But are you certain that it wouldn't cause the temperature to climb past the absolute maximum ratings of the electronic components, including LED and that lithium cells won't be heated beyond safe temperature?

PS:
The first setup reached a temperature of 110F.

I'm doing another run with Minimag 2AA LED with freshly charged batteries, this time with temperature probe wrapped around it and inside a thick layer of blankets.

Long John said:

I tested my Fenix 2,30m under water, no leak, no water insight and the light worked well.
I guess, your Minimag would get wet inside

This was a real world test. I'm not intended to cover my light with a blanket, because it will surely not to be cold.
But if I would do it, I'm sure it would survive.

My light is better than yours :lolsign:

Best regards

____
Tom

Click to expand...

Please do it. Load it with fully charged NiMH, or better yet Energizer L91(they don't say not to) then let it run well insulated, preferebly with a temperature probe attached and record the maximum temperature reached.
i

A thermocouple was secured to the Maglite 2AA LED body and secured with a ribbon tightly wrapped around it. The end of the ribbon was taped to prevent it from coming loose to maintain good contact between the sensor and the flashlight under test.

The entire assembly was wrapped around multiple times in a blanket, then covered with a tarp to keep the air from infiltrating.

The light steadily gained temperature, then hit a ceiling at 51°C (~125F). At this point, the batteries were replaced with a set of freshly charged 2.1Ah NiMH cells. The temperature rapidly dropped to approximately 40°C. I believe this is due to the fact replacement batteries were at room temperature.

Slowly, the temperature gained, but again, stopped at 125F. It's either reaching equilibrium with dissipation on its own, or the driver is backing off the output to prevent further temperature rise.

LED_Museum will be performing a similar test for me with the Fenix L2T tomorrow. Thank you Craig.

Long John said:

I tested my Fenix 2,30m under water, no leak, no water insight and the light worked well.
I guess, your Minimag would get wet inside

Click to expand...

I don't think my 2AA LED Maglite will lose to a generic, but I don't like to assume, so experiment is being conducted.

This was a real world test. I'm not intended to cover my light with a blanket, because it will surely not to be cold.
But if I would do it, I'm sure it would survive.

My light is better than yours :lolsign:

Click to expand...

Oh yeah? :rock:

Result:

Water did not infiltrate inside. Not a single drop found inside and no fogging on the lens.

Handlobraesing said:

What high power (Luxeon 1W or higher) flashlights...would the temperature be limited below what could cause a permanent damage to itself or start a fire?

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Good job Handlobraesing - I salute your efforts to study this issue.

Judging from some of the responses in this thread, some people don't appreciate what a desirable feature thermal limiting is.

Desirable on any LED light, it is especially important for plastic body lights. Most reasonably-priced dive lights, most headlamps, and most saftey-rated industrial lights have plastic bodies which hold in the heat.

I'd guess that many of these lights, possibly most of them, have some sort of limiting to prevent thermal runaway, damage to the emitter, and even damage to the body of the light as happened to Handlobraesing's K2 headlamp.

Thermal limiting is a big plus on any light, at least so far as I'm concerned. Thermal limiting on inexpensive lights, like the Mag lineup, makes them an even better value.


.

Handlobraesing said:

I'm not asking how it would apply to you in specific.

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Um...... ok. I am not that great at speaking for others. I also understand that different people have different preferences, which is why I qualified my post with "for me." You asked Tom if he thought it was a foreseeable misusage. Since I can't speak for anyone else, I just thought I'd share that I didn't personally find it to be a problem.

Using your reasonable judgment, would you say it is reasonably foreseen that the light will be accidentally activated in storage or put in pocket while turned on and forgotten about?

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Using my reasonable judgment, I'd say that reasonable people should be a little more reasonable with their tools, and try to purchase reasonable tools that are reasonably well made. For a reasonable man like you, I guess this means purchasing lights with reasonable thermal protection. For a reasonable man like me, this means taking reasonably responsible measures not to do reckless things with my lights... like put an activated light into my pocket, or put a light into a pack without engaging the already reasonable lockout feature.

Why do microwave ovens have interlocked door instead of cautioning user to "do not open while in use or activate before closing door" ?

Click to expand...

I'll ask Jack Donaghy next time I see him.
Of course, if lights left on in packs gave people cancer, I'm sure protection would be built into the lights.

There is a beam in each door, because it is reasonably foreseen that you maybe invovled in a side impact accident.

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Well, no matter how great a driver I am, I can't prevent another car from t-boning me while I drive through a green light. But as long as I've owned flashlights, none of them have gotten drunk and decided to turn themselves on and hop in my packs.
I don't need my lights to compensate for user error.

PS: The first setup reached a temperature of 110F.

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The RockRiver light that started you on this crusade is obviously defective, particularly since not every user of that light has reported the same findings. As such, why do you believe that its hypothetical thermal protection would have been effective? I just don't see the logic in assuming that a company could get thermal protection circuitry right when they can't even get a simple heatsink right.

Despite the fact that you object to me qualifying my original post by referring to my personal use/experience, I thought it was quite fair. That is, I personally don't need a light to cover my butt in terms of thermal buildup caused by user error. I do expect a light to be built with a proper heatsink and design such that normal use will not destroy it (a criterion which your RockRiver obviously did not meet).

There is a long list of things I would prefer to see in a light before I'd care the slightest bit about thermal protection. Your list of priorities is different.

Going along with our running tally of analogies... It may well be reasonably foreseen that some yahoo will pick up a handgun with no magazine inserted but a round in the chamber and negligently discharge the weapon. This is why some firearms manufacturers use magazine disconnects, external safeties, etc, even though my scenario describes user error. I personally don't want a magazine disconnect on my weapon, nor do I want an external safety. This is why I own a Glock. You might think Glocks are flawed in their inherent design, just like you think lights lacking thermal cutoff are inherently lacking in their design. This is the beauty of a free market, I guess.

I only posted in this thread in the first place to say that not everyone might want what you want in a light, even if your desired feature holds safety value. I would have posted a similar response if you had started a thread wondering why Glocks (or other weapons) did not feature magazine disconnects and how you thought that was shortsighted.

But I guess you don't want personal opinions/experience on this matter, or how this might apply to individuals. Not sure how else people can respond though.

I just got the result from LED_Museum on Fenix L2T.

After two hours in poor ventilation, Fenix L2T escalated to dangerously hot
68C/154F

Handlobraesing said:

I just got the result from LED_Museum on Fenix L2T.

After two hours in poor ventilation, Fenix L2T escalated to dangerously hot
68C/154F

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If you loosen the head to put the light in low mode then it will come on at the lowest level and not heat up. 154F probably isn't enough to damage the LED before the cells run out of juice. It probably isn't enough to cause a catastrophic reaction in the cells because that usually takes temperatures above the boiling point of water.

chevrofreak said:

If you loosen the head to put the light in low mode then it will come on at the lowest level and not heat up. 154F probably isn't enough to damage the LED before the cells run out of juice. It probably isn't enough to cause a catastrophic reaction in the cells because that usually takes temperatures above the boiling point of water.

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That's not the point. The purpose of the experiment was to see how well the light can manage thermal runaway in foreseeable adverse conditions.

hmmm L2D-CE with lithium cells wel insulated in blanket on turbo mode. If it has integral thermal protection, it wouldn't even be an issue. Someone will have to test it....

If there are forseeable adverse conditions, then why not loosen the head to eliminate the chance of the light turning on in high mode which could damage it? Makes sense to me, which is why that's how I do it.