# Why do my LED lights keep dying?



## jeffkruse (Sep 26, 2011)

I have 2 Fenix TK12’s, 1 PD31, 1 TK30, and 2 iTP A1 EOS

I use the TK12, PD31, and TK30 caving. They are on high the entire time. They haven’t been flooded or dropped but they do get banged around.

My first TK30 had a low output after only a dozen hours of use. My warranty replacement TK30 also has about 50% output after 10 hours of use.

Now one of my TK12’s has a reduction of output about 50% but this light lasted maybe 100 hours at most. I have switched the head around, cleaned contacts, ect. It’s the light head.

One of my iTP pocket lights died after only a few hours of use.

I love these lights but this sucks. Should I be able to use these lights at full power all the time? Are these kind of LED lights meant to be used frequently or just occasionally? 

Is this just my bad luck or I should know better and not use the light at the brightest setting?


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## B0wz3r (Sep 26, 2011)

jeffkruse said:


> I have 2 Fenix TK12’s, 1 PD31, 1 TK30, and 2 iTP A1 EOS
> 
> I use the TK12, PD31, and TK30 caving. They are on high the entire time. They haven’t been flooded or dropped but they do get banged around.
> 
> ...


 
You must be doing something with your usage that is causing it. Even the less expensive ones you mention, the iTP shouldn't behave that way, and you shouldn't see that kind of behavior across such a wide selection of lights.


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## jorn (Sep 26, 2011)

Sounds like you killed a itp, and you might need to check your 18650 batteries or charger? pd31,tk12,tk30 i guess you use 18650 of some sort.


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## tre (Sep 26, 2011)

What kind of batteries are you using?


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## jeffkruse (Sep 26, 2011)

Yes, all 18650 charged to 4.15 Volts. 

Of which, I have had 3 of 10 cells fail. They are a mix of expensive Redilast and cheap Ultrafire protected cells. I had one Redilast and 2 Ultrafire cells go bad. The charger is a TL-100 Universal Li-ion charger and I check the voltage with a DMM.


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## fyrstormer (Sep 26, 2011)

Get a McGizmo. You can beat the living hell out of it and it won't die. Even the lense is made of artificial sapphire instead of glass.

Keep a Fenix in your pocket just in case something goes horribly wrong, like you drop the Gizmo somewhere you can't reach.


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## nbp (Sep 26, 2011)

Are you epileptic by any chance?

I heard something about people with epilepsy having odd electrical currents that make electrical devices go wonky. Never could find any good peer reviewed material on it but it sure sounded like something I wanted to research. Do you fry other devices too?


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## shao.fu.tzer (Sep 26, 2011)

Because you should invest in some nice Surefires...  I started on Fenix long ago and after the last few duds I picked up, I just gave up...


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## Streamer (Sep 26, 2011)

My Gosh Man...if you can pick 6 top of the line flashlights and they all go haywire on you....you should hurry out and purchase Lotto Tickets....I mean, what are the ODDS? 

UNBELIEVABLE !!!


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## Shooter21 (Sep 26, 2011)

Streamer said:


> My Gosh Man...if you can pick 6 top of the line flashlights and they all go haywire on you....you should hurry out and purchase Lotto Tickets....I mean, what are the ODDS?
> 
> UNBELIEVABLE !!!


 yes thats crazy none of my lights ever failed me


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## offthetrail (Sep 26, 2011)

One of my iTP A1 EOS lights recently died as well. I carried it every day for 6 months on my keychain and I tried to use it the other day and it was dead. New battery didn't change anything...


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## jorn (Sep 26, 2011)

If it's not the batteries, this is my second guess.
Do you use some glowes when you cave? 
Many hi lumen led lights reqiers you to hold the light in the hand when running on full power for long times. The heat builds up and needs somewhere to go. Too mutch heat will slowly kill the led. The blood in your hand transfers a lot of heat away from your light, and straight into a flashoholic's heart (you are a a big watercooling system seen trough a flashlights eyes). I guess they can overheat if your in a hot cave, wearing glowes that helps insulate the light from the enviroment and insulates the heattransfer needed from the light to your hand. 
Funny that the new hi power lights needs the help of the user to survive. Symbiosis, i guess the hi lumen lights love you just as mutch as you love them :grouphug:


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## shao.fu.tzer (Sep 26, 2011)

I firmly believe that there are some people who emit electromagnetic fields that disrupt electronics. My stepmother has to buy a new cell phone every month... really... she never drops them and barely uses them... We've concluded that she must give off a weird field... She claims to have broken countless calculators and watches through her life as well... all within a month of two of owning them... 

Maybe you should just stick to fire on a stick... it's received excellent reviews here - plus it's a time tested design...


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## jupello (Sep 26, 2011)

The reduced output makes me think that the LED's have been overheating.


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## jabe1 (Sep 26, 2011)

Try using multiple, slightly under-driven lights... or get a Peak and a Surefire. (you do need a backup after all)


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## jorn (Sep 26, 2011)

jupello said:


> The reduced output makes me think that the LED's have been overheating.


 Yep, i think the tk12 lived the longest because it's draws less wattage than the tk30. And is way more chunky so it can store more heat than the pd31 before the temprature gets critical.
I always used thick gloves when caving and used my 2xaa maglights nonstop constantly only rupted by battery changes. That would have been bad for a powerled.

I think you use too mutch juice for too long, and if thick gloves is in the picture, it will make it worse for a led.


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## MikeAusC (Sep 26, 2011)

shao.fu.tzer said:


> . . . Maybe you should just stick to fire on a stick......


 
But make sure you hold it with ClassIII insulation rated gloves - otherwise your "electromagnetic field" will set fire to the bottom as well


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## burntoshine (Sep 26, 2011)

i use my lights everyday and don't have any problems. i stay away from 18650 and all the other uncommon batteries. they seem so unnecessary; at least for my purposes. i mostly use lights that take AA, AAA, and CR123 batteries. i have a couple 7777 CR2 minis that i use a lot. CR2s are the most oddball batteries that i mess with. and i prefer to use just enough light for the task; that way i don't waste energy and the LEDs stay relatively cool. those aren't the main reasons i'm conservative with brightness, but they're great pluses. i just like low light. however, i like the ability to have "really bright" if i want it; i just don't use max and high modes all the time. my bike lights are on high (not max) most of the time when i use them, but i find that necessary to light up a nice big area in front of me.

you might consider changing your usage. maybe try to use the medium modes more. i hope your luck changes.


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## RI Chevy (Sep 26, 2011)

Maybe you could try a G2 Nitrolon or some other plastic type flashlight to see if they work any better?


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## hellokitty[hk] (Sep 26, 2011)

If you're running them on high all the time with gloves on, I'm going to guess that they're too hot.


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## fyrstormer (Sep 26, 2011)

shao.fu.tzer said:


> I firmly believe that there are some people who emit electromagnetic fields that disrupt electronics. My stepmother has to buy a new cell phone every month... really... she never drops them and barely uses them... We've concluded that she must give off a weird field... She claims to have broken countless calculators and watches through her life as well... all within a month of two of owning them...
> 
> Maybe you should just stick to fire on a stick... it's received excellent reviews here - plus it's a time tested design...


Any electromagnetic field strong enough to disrupt electroncs would be detectable using a simple compass. Science doesn't require belief.

Has she ever bought a really good, expensive phone? Or does she buy the cheapest ones she can get, "because they'll break anyway"?


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## MikeAusC (Sep 26, 2011)

fyrstormer said:


> Any electromagnetic field strong enough to disrupt electroncs would be detectable using a simple compass. . . . ?


 
No, compasses can only detect steady magnetic fields. They can't detect alternating magnetic fields as from mains wiring or any electromagnetic radiation which is reversing many times a second.


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## uknewbie (Sep 27, 2011)

hellokitty[hk] said:


> If you're running them on high all the time with gloves on, I'm going to guess that they're too hot.


 
Careful, that kind of common sense talking may lead to trouble! 

Yes, overheating was the first thing I thought. They are designed I imagine to have airflow (other than in a cave) pass by them to cool them, or your bare hands to do the job.

You seem to have quite a specialist usage so maybe you need a light more designed to handle this.


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## BoarHunter (Sep 27, 2011)

shao.fu.tzer said:


> I firmly believe that there are some people who emit electromagnetic fields that disrupt electronics. My stepmother has to buy a new cell phone every month... really... she never drops them and barely uses them... We've concluded that she must give off a weird field... She claims to have broken countless calculators and watches through her life as well... all within a month of two of owning them...
> 
> Maybe you should just stick to fire on a stick... it's received excellent reviews here - plus it's a time tested design...


 
Nonsense !

Truth is, she is a witch and should be burnt like anyone believing in witchcraft !


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## jeffkruse (Sep 27, 2011)

I am caving in Puerto Rico. It is about 80 degrees and can be 100% humidity in the cave. I do wear blue atlas gloves but I don't hold the light by the head.
It's a big disappointment. Where as this isn’t cave diving so a reliable light isn’t so important. It could become a problem if all three of the lights I carry went bad.
I am thinking of buying the new Rude Norra Headlamp from Little Monkey http://littlemonkeycaving.co.uk/Overview.aspx but I am worried that if I spend that much money I am going to have problems.


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## manoloco (Sep 27, 2011)

sounds to me like its simply the constant bumping what damages your light, the half output light could have had its led dome dislodged and damaged hence the reduced output, once bought a used SF L1 that was like that, and the output was reduced.

get an HDS, it has roots on its design related to caving.

A headlamp is a must when caving, and i would worry more about your head than the light if you are planning to bump them , still as this will probably be your primary light while caving, devote more resources to it.


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## shao.fu.tzer (Sep 27, 2011)

fyrstormer said:


> Any electromagnetic field strong enough to disrupt electroncs would be detectable using a simple compass. Science doesn't require belief.
> 
> Has she ever bought a really good, expensive phone? Or does she buy the cheapest ones she can get, "because they'll break anyway"?



She used to buy expensive phones until she got tired of them breaking on her... now she buys older-tech phones, which should still be quite reliable...



BoarHunter said:


> Nonsense !
> 
> Truth is, she is a witch and should be burnt like anyone believing in witchcraft !



Well, I did stick her up on a balance scale with a duck and they DID weigh the same...


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## KenAnderson (Sep 27, 2011)

Max brightness rarely has a duty cycle of 100%, often a 100% dc is found at 20% of max brightness, but can vary based on design.


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## richpalm (Sep 27, 2011)

Be more conservative... have a light that's bright enough for your use that you can set to medium and run it that way. Full power is not good for more than a few minutes in a lot of cases. 

Rich


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## Jash (Sep 27, 2011)

Wow! A TK30 on high for caving? That's just redicilous. I've only been caving a couple of times, but I do a bit of night climbing and 30-50 lumens is more than enough once it's properly dark.

I'd guess, like others that you're overheating the LEDs. I mean, you don't buy a car and drive it at it's maximum revs all the time do you, and expect it to last very long.


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## jeffkruse (Sep 27, 2011)

I don't think that is the same thing. 
I see that some lights only let you be in turbo mode for 5 minutes then they switch to high. If the TK30 and TK12 suffered from this then why don't they do that also? I get the feeling that 50% say you shouldnt use a light on high all the time and the other 50% say you can with no problems???


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## jeffkruse (Sep 27, 2011)

And yes the TK30 is nice for caving. We have some big caves here. I also use it sparingly because it only lasts 90 minutes or so on high.

I use a head lamp also but I like a small handheld (on a lanyard) to shine at my feet. It's much easier to move your handheld light around then it is to move your head/helmet/headlamp around.


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## luceat lux vestra (Sep 27, 2011)

I would suggest a thermal regulated light, because........THEY CAN'T OVERHEAT!!!!!!!
Maybe try one of these?
http://www.4sevens.com/product_info.php?cPath=297_406&products_id=2617
http://www.4sevens.com/product_info.php?cPath=297_330&products_id=2621
http://www.4sevens.com/product_info.php?cPath=297_406&products_id=2655
4sevens says = *Thermal Regulation*: This means it can take serious abuse and be exposed to harsh conditions, but it will automatically control its output to protect its own guts. That means you don't worry about your light - you just use it.

Hope this helps.


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## fannin (Sep 27, 2011)

offthetrail said:


> One of my iTP A1 EOS lights recently died as well. I carried it every day for 6 months on my keychain and I tried to use it the other day and it was dead. New battery didn't change anything...



i was always happy with my a3 eos's until i got one that wouldn't go into high mode after a week or so, i thought they were the most consistent lights i ever had (i owned a few and gave away a few), all the same neutral tint, all the same clean beam, always the same good f&f (and awful pocket clip and keyring that both came straight off and went into the trash, even the ones i gave away, that pocket clip is a liability), then i got that dud and the guy wouldn't replace it after i bought loads of them from him so i never bought another one

surprised to hear your bad luck with fenix though, like the other guy said maybe you just fry stuff, i know someone who does that to loads of things, he turned my pc on once and blew the motherboard. that ever happen to you?


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## gcbryan (Sep 27, 2011)

Hey Jeff!

I think you're probably just tough on those lights. What kind of light are your caving buddies using and are they having similar problems?

Aren't their dedicated caving lights designed for the rougher treatment?


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## TooManyGizmos (Sep 27, 2011)

~

I went through several original ITP A3's (AAA).

They all died within the first 6 months .

I've posted warnings about it many times .

Why didn't you heed my warning ?

~


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## jupello (Sep 27, 2011)

jeffkruse said:


> I don't think that is the same thing.
> I see that some lights only let you be in turbo mode for 5 minutes then they switch to high. If the TK30 and TK12 suffered from this then why don't they do that also? I get the feeling that 50% say you shouldnt use a light on high all the time and the other 50% say you can with no problems???


 
Maybe it's because some CPF'ers would whine a lot if the runtime curve on max was not flat until batteries are dead? The regulated Led Lensers for example do just that (Automatically step down the brightness from max to protect the led) and they get lots of bashing here for doing so.

Also, the environment you use the light in matters a lot. If you would have used your lights in some cooler place they might still be working 100%. So it all depends on what conditions you use your light in. If you are in cold, windy place, then the LED wont overheat that easily and you can use MAX for longer times. If you are in warm place where air stands still, you should avoid using the max brightness for too long unless you are ok with reduced life span of your LED's.
Of course the light's properties matter a bit too. A light with bigger heatsink, or less overdriven led would last longer.


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## march.brown (Sep 27, 2011)

I find that if it is very dark (virtually black dark) , then I don't need a very bright light ... My eyes get used to a low level of illumination ... If I need more light , I have two more levels to play with ... Usually the low on my ITP's (A1 , A2's and A3's) is fine ... All my many Solarforces (all are three modes) are also great on low , though the next click puts them on high (if needed) for when I'm out with the dog.

It's amazing how little light you can manage with when it is black dark ... The medium and high modes can be used for seeing further into the distance.
.


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## SaVaGe (Sep 27, 2011)

shao.fu.tzer said:


> I firmly believe that there are some people who emit electromagnetic fields that disrupt electronics. My stepmother has to buy a new cell phone every month... really... she never drops them and barely uses them... We've concluded that she must give off a weird field... She claims to have broken countless calculators and watches through her life as well... all within a month of two of owning them...
> 
> Maybe you should just stick to fire on a stick... it's received excellent reviews here - plus it's a time tested design...


 
If this is his case, he should buy an HDS. its EMP proof.


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## SaVaGe (Sep 27, 2011)

This situation worries me now. Are the manufacturers lying? They say led last 50,000 hours or better. But whos has time to test for at least 500 hours continious?. I guess he proved it. After 100 or so hours, the led diode just dies....... Hmmmmmmmm anyone care to chime on my thought?


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## TooManyGizmos (Sep 27, 2011)

~

I think most of the time ... it's the driver circuit that fails.

~


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## TyJo (Sep 27, 2011)

jeffkruse said:


> Yes, all 18650 charged to 4.15 Volts.
> 
> Of which, I have had 3 of 10 cells fail. They are a mix of expensive Redilast and cheap Ultrafire protected cells. I had one Redilast and 2 Ultrafire cells go bad. The charger is a TL-100 Universal Li-ion charger and I check the voltage with a DMM.


I would say the cells are what is wrong, or the charger, or you are discharging the cells too deep and leaving them that way? The TK30 can run on 1 or 2 18650s, 1 cell ~halves the output. If one of the cells was crap it could be voltage sagging or something similar causing the output to drop. Although it does seem like the LED is overheating and aging prematurely, I think someone would have exposed Fenix's heat management issues by now if that was the case. Could it be possible that the lights only seem 50% depending on your environment and/or level of dark adaptation? The individual variations in electromagnetic fields stuff is false IMO.


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## jupello (Sep 27, 2011)

SaVaGe said:


> This situation worries me now. Are the manufacturers lying? They say led last 50,000 hours or better. But whos has time to test for at least 500 hours continious?. I guess he proved it. After 100 or so hours, the led diode just dies....... Hmmmmmmmm anyone care to chime on my thought?



That 50 000 hours is how long CREE estimates their LED's to last. But that's only on certain temperature with certain drive current. Flashlight manufacturers tend to drive the LED's with much higher currents than what CREE tested them with..just to get the big lumen numbers to boast with.

The extra current also generates extra heat, and LED's are sensitive to heat. When the LED is running too hot, it degrades faster than it normally would. It wont just suddenly snap and go off like light bulb (unless you REALLY abuse it), it just goes dimmer and dimmer over time. Small flashlights just do not have enough surface area to dissipate all the heat when the LED's are driven at really high currents.

So in reality you're getting way less than the 50 000 hours on max with most lights. 
But don't fear, the good flashlight manufacturers still try to design their lights so that you would get decent amount of usage out of their lights under "normal" conditions.


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## Scubie67 (Sep 27, 2011)

Caving is pretty rough on equipment(I am assuming your dry caving ,no sumps or anything like that).I know from cave diving which other than water pressure, is probably less impacting to gear than dry caving and I have roughed up gear without even knowing it.As others have said might be your batteries ? To have that many lights with problems not too sure.Thats why cavers obey the rule of thirds don't we and carry at least 3 lights right?


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## jeffkruse (Sep 28, 2011)

Yes I am hard on these lights but I would have expected to flood, break the lens, dent, or tear the switch boot. Not have problems with the brightness. These are dry and wet caves with shallow short sumps to hold your breath through. Got to love freediving in 0 vis through a sump, not.

I have tried several pairs of batteries in the TK30 with the same results.

All the cells I have are protected and yes on occasion I do take them down to the point they shut off. I can see (really I can’t see because they are protected) how I might be killing the cells. However all the cells I put in the TK30 are at 4.15V and those same cells work great in my PD31.

Gray, I am cutting edge when It comes to lights here. Some people do use a Sten and that is bullet proof but my PD31 is just as bright. Heck I even considered a Scurion but at $1500 and with my low salary here in Puerto Rico I just can justify it (Yet). I use a 200 lumen Apex and only have problems with getting water in it.

Yes my eyes do adjust to the low light in a cave but with the low light I see much much less. I am in a cave to SEE it. It’s not enough for me to only see 50 feet in front of me. 

I want a good bright IPX8 or better, floody headlamp. 600 lumens or more using 2, 3, or 4 18650 2600 – 2900 mAH batteries with a price of less than $400.

A headlamp is important in a cave but I really like my one cell 18650 handheld lights. It’s so much easier to move through a cave with one. There are times I have even forgotten to turn on my headlamp because my handheld is so much better.


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## Scubie67 (Sep 28, 2011)

Ipx8 lights are supposed to be good to 6 feet for 30 minutes,I don't know if the sump parts you are in may exceed this time/depth limit ,if you taking them apart and there is no flooding as far as you can tell I guess that wouldn't be the problem most likely.You may need to look into maybe getting a dive light that is also can be used above the waterline if you are getting a lot of light flooding


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## Launch Mini (Sep 28, 2011)

shao.fu.tzer said:


> I firmly believe that there are some people who emit electromagnetic fields that disrupt electronics. My stepmother has to buy a new cell phone every month... really... she never drops them and barely uses them... We've concluded that she must give off a weird field... She claims to have broken countless calculators and watches through her life as well... all within a month of two of owning them...
> 
> Maybe you should just stick to fire on a stick... it's received excellent reviews here - plus it's a time tested design...


 
I agree. 
My father could not wear battery operated watched. They would stop working in very short time. Howeve a mechanical watch was fine for him.
He could also "witch wells" with a willow stick. Would locate water sources and their depth with freaky accuracy. People all over the province requested his services before they dug for wells.


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## nbp (Sep 28, 2011)

Here's another thing I was thinking about. Every cave I have ever been in was super dark, there is zero ambient light. A match will light up a whole cavern. Why do these lights have to be on high all the time anyways? If I can navigate around my 'dark' house with all kinds of little blinky lights all over the place with less than a lumen, even a medium output of something like 60 lm should be way more than enough to see what is going on, and would be far more sustainable for long periods of time without damage, especially if these caves are hot inside. I just don't see how hundreds of lumens would be necessary for more than short bursts of a few minutes at a time. :thinking:


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## Sparky's Magic (Sep 28, 2011)

Perhaps it's time to go down the HDS path with an MD3 - XM-L Hi-Low as a back up. Neither of these lights will let you down nor will they over heat: The back-up XM-L will light up any spectacular large formations, caverns, lakes etc. brilliantly.


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## psychbeat (Sep 28, 2011)

dont emitters usually turn blue when they are overheated seriously?

Id bet on the drivers/electronics messing up over the emitter.

I run my 2.8a dual XP-G til cut off quite often and the emitters are fine.

even if the duty cycle is more than cut in half it seems more likely something else
will fail before they do....or Ill replace them with an upgraded emitter 

bumping around etc is more of a problem than heat. I killed my mini123 in the
dryer (which was on air only) when I left it in the pocket of my raincoat.

I had previously run that on High til cutoff plenty of times using a 16340- yes it got HOT!


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## TyJo (Sep 28, 2011)

Nbp I was wondering the same thing. I don't know how it can be accurately determined that a light is 50% less bright in such circumstances as well, it's all relative to ambient light and the users dark adaptation level (100 lumens can throw a mile perception wise until you get used to it, then you need to increase lumens). As far as protected cells are concerned, it is still a bad idea to leave the cells in a discharged state, it can damage the cell or reduce capacity permanently if this is done for extended periods. Additionally, I don't like to rely on protection circuits if it can be avoided, protection circuits can fail, especially when they're in a light that is getting banged around.

I'm not doubting the OP, but the odds of so many quality lights failing/dimming is remarkable (it's not from his electromagnetic fields!). I have disassembled the head of the TK30 (to put a warm MCE in) and the only thing I can think of is if the thermal compound between the LED and heatsink has been jarred loose causing poor heat transfer to the heatsink. This could cause the LED to age rapidly. I doubt this to be the case but I can't think of anything else to be the issue (assuming the TK30 is changing modes, etc. properly).


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## march.brown (Sep 29, 2011)

If all members of the caving team use lowish modes , there should be no need to use higher modes ... It is only when someone insists on flashing a high power torch about that you're eyes need more lumens ... It is surprising how little light you actually need once your eyes become accustomed to a lower level ... It only takes one person to put their torch on high , to force all other team members to do the same.

Sit in the black dark with all the lights switched off for a minute or so then put the light on low ... It is amazing how much you can see ... Snag is when you shine the torch directly onto white limestone , you lose your night vision ... This is much worse if you are using a high power torch ... Ideally you need to switch the lights off for a minute to get your night vision back again.
.


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## jeffkruse (Sep 29, 2011)

There are many who think 50 or 100 lumens is enough to cave with. Sure I could make my way out of the cave with even less. That is not the point. I want to SEE the cave not just pass through it. Our caves may be hundreds of feet tall and hundreds of feet before the next bend. I want to see it all not just whats in front of me. With more light I pick up more detail. Our caves are covered in mud and bat guano so they are mostly dark. That’s why I use a TK30 and PD31. IMO they should be able to be used at full power indefinitely. 

Based on the responses from this thread it looks like many people say I shouldn’t be having this problem and many people think I shouldn’t be using them on high. Then there is the group that want me to cave by candlelight. J


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## psychbeat (Sep 29, 2011)

I think u need to start driving 54 in the left lane from now on...


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## jeffkruse (Oct 10, 2011)

*I killed my 5th light, why me?*

What’s going on! My first TK30 had low output after only a dozen hours. It was replaced under warranty. The replacement also only lasted about 10 hours and is being replaced under warranty.

One of my iTP pocket lights died after only a few hours of use.

One of my TK12’s has a low output after about 100 hours of use.

Now my cherished PD31 also has a low output after about 75 hours of use!!!!!! I was just holding it in my hand not even moving it and the output just dropped. 

The lights still turn on and switch modes correctly but have a reduced output of more than half. I switched batteries (surefire, readylast), cleaned contacts, switched heads, shorted switched, ect. The batteries are fully charged (4.2V).

I use these lights caving and they have not been flooded. I am hard on them but when they go bad I am just holding them in my hand.

I use them on high power all the time. My Apex headlamp is used on high and it hasn’t had this problem (although it does flood when submerged).

Are these lights tested for longer than 100 hours? I want a quality 18650 light like the PD31 with an output of 300, 500, or more lumens.


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## ragweed (Oct 10, 2011)

*Re: I killed my 5th light, why me?*

Sounds like your running them hot with the 18650 batteries. Is the emitter turned brown?


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## xul (Oct 10, 2011)

*Re: I killed my 5th light, why me?*

Measure the current from the batteries and the voltage across them. If only one failed I'd say it was an 'infant mortality' failure but they are all failing.http://en.wikipedia.org/wiki/Bathtub_curve


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## jorn (Oct 10, 2011)

*Re: I killed my 5th light, why me?*

I get deja-vu reading this thread.


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## jh333233 (Oct 10, 2011)

*Re: I killed my 5th light, why me?*

Overloading LED will cause them to degrade faster
Or driver getting fried
Ive ever tried to use 8.4V on a single cell driver
Bright, ramping down, burnt


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## dosei-45 (Oct 10, 2011)

*Re: I killed my 5th light, why me?*

...holding in your hand...or your gloved hand?

http://www.candlepowerforums.com/vb...-do-my-LED-lights-keep-dying&highlight=caving


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## LED_Thrift (Oct 10, 2011)

*Re: I killed my 5th light, why me?*



jorn said:


> I get deja-vu reading this thread.


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## AutoTech (Oct 10, 2011)

*Re: I killed my 5th light, why me?*

It's interestung though. I wonder how many people out there have run a PD31for 75 hours?! I've probably not even run mine for 75 seconds lol.

I often wonder how long these high power lights actually last, maybe you've just found out.

It can't be that you've just been unlucky, surely!


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## jeffkruse (Oct 10, 2011)

*Re: I killed my 5th light, why me?*

deja-vu - Exactly! Because it happened again this weekend with my PD31. The light was loosely held in my gloved hand. It was in and out of the water so cooling shouldn’t be an issue (this time anyways). 

The drivers should be able to handle more than 4.2 volts. I am using ONE 18650, not TWO 123’s. Over voltage is not an issue.

I love these little lights but I want one that lasts more than 100 hours! The cases are bullet proof, no issues there.

I suspect there are very few people who use their lights on full power for hours at a time once a week. With the PD31 and TK12 I think they don’t output “full Power” when the battery voltage drops. That means these lights are not at full power the whole time. I think the TK30 may be at full power the whole time but I only use that light for 30 minutes at a time.


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## luceat lux vestra (Oct 10, 2011)

jeffkruse said:


> There are many who think 50 or 100 lumens is enough to cave with. Sure I could make my way out of the cave with even less. That is not the point. I want to SEE the cave not just pass through it. Our caves may be hundreds of feet tall and hundreds of feet before the next bend. I want to see it all not just whats in front of me. With more light I pick up more detail. Our caves are covered in mud and bat guano so they are mostly dark. That’s why I use a TK30 and PD31. IMO they should be able to be used at full power indefinitely.
> 
> Based on the responses from this thread it looks like many people say I shouldn’t be having this problem and many people think I shouldn’t be using them on high. Then there is the group that want me to cave by candlelight. J


I completely understand, I would not carry a big bright light to use it at 60 lumens!!:shakehead My current EDC is a Quark aa with a 14500 for low light uses and then I carry a Quark 132x2 turbo X programed for max and strobe. 
If I were you I would try a thermally regulated light; with my turbo X, I have never noticed it dialing down, but it still keeps my LED from going kaput [I think anyway] Hope this is relevant.
Luceat lux vestra
Let your light shine


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## davecroft (Oct 10, 2011)

jeffkruse said:


> Based on the responses from this thread it looks like many people say I shouldn’t be having this problem and many people think I shouldn’t be using them on high. Then there is the group that want me to cave by candlelight. J



Only a CPF'er would switch on a light and say 'Wow! Look how dim that is!'


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## nbp (Oct 10, 2011)

Hey, he can blast away in 100 degree temps with his lights on turbo for 3 hours if he wants, but then he can't complain when they don't last long. It seems to be general trend that it's not working out. 

Again, go ahead and use 500 lms to light up a big cavern for a few minutes at a time, that should be no problem. But for general navigation in zero ambient light conditions, a lower mode should be more than sufficient, and clearly, more practical in the long run as you'll wreck a lot less lights.


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## jeffkruse (Oct 10, 2011)

nbp said:


> Hey, he can blast away in 100 degree temps with his lights on turbo for 3 hours if he wants, but then he can't complain when they don't last long. It seems to be general trend that it's not working out.
> 
> Again, go ahead and use 500 lms to light up a big cavern for a few minutes at a time, that should be no problem. But for general navigation in zero ambient light conditions, a lower mode should be more than sufficient, and clearly, more practical in the long run as you'll wreck a lot less lights.



Wow, so I can’t expect to use my light on high for the burn time of the battery? Also, it’s not 100 degrees it’s less than 85.

So what light, 18650, 300+ lumen, light can be used on high indefinitely? None?

You seem to want me to cave by candle light? What’s so wrong with wanting more light? I bet I see far more with my bright light than you do with something only ¼ as bright.


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## jupello (Oct 10, 2011)

jeffkruse said:


> Wow, so I can’t expect to use my light on high for the burn time of the battery? Also, it’s not 100 degrees it’s less than 85.
> 
> So what light, 18650, 300+ lumen, light can be used on high indefinitely? None?
> 
> You seem to want me to cave by candle light? What’s so wrong with wanting more light? I bet I see far more with my bright light than you do with something only ¼ as bright.



Sure, you CAN run them all the time on full power, but as you see - they don't last long at that level under those conditions.

One solution could be to find a light that has really great heatsinking, or that is thermal regulated. Or you could switch to incadescent/HID lights since they should not be so picky about the temperature.


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## red02 (Oct 10, 2011)

jeffkruse said:


> Wow, so I can’t expect to use my light on high for the burn time of the battery? Also, it’s not 100 degrees it’s less than 85.
> 
> So what light, 18650, 300+ lumen, light can be used on high indefinitely? None?
> 
> You seem to want me to cave by candle light? What’s so wrong with wanting more light? I bet I see far more with my bright light than you do with something only ¼ as bright.



I agree 100% if a manufacturer rates their light for 40,000 hours AND includes a high mode with 200+lm, why shouldn't it be reasonable to expect that light to last? I've actually had a zebralight H501 die on me, now that I think about it I did run it at full power for most of it's life. This makes me wonder how many people actually use their lights like this... I get the feeling that most people just turn on high mode for a few minutes to marvel at the capabilities then back to off, but there isn't a huge majority that NEEDS to use their on high consistently.

Personally I prefer lower light levels, but it would be nice to know that I could actually depend on my tools to work -as advertised-.

Its wrong to be blamed for using lights according to their instructions.


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## alpg88 (Oct 10, 2011)

i think you need to closely examine your failed lights, with dmm, and a lot attention, i,m pretty sure dead lights will tell you why they died, if you look hard enough, cuz now we can only guess.
may be you should try incandecent lights, there are less things to fail, and heat is no issue, i think you will have less problems. you would need to carry 2x as much of spare batteries, and just in case a spare bulb too.


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## chmsam (Oct 10, 2011)

As has been stated before the most common reasons for LED failure are overheating, over driving, and moisture. There are plenty of examples of those in this thread. If however those can be ruled out and an LED still fails I would do the following in no particular order:

1) check for signs of corrosion or oxidation in the light or on the battery or batteries.
2) check for signs of battery failure like leakage, venting, or swelling.
3) use a DMM to check for unusal drain or shorts, continuity throughout the circuitry, and/or unusual voltages.
4) check the battery or batteries with a battery tester -- it is not enough just to know the voltage.

I do a regular and frequent preventive maintenace on my lights by using only quality batteries with known purchase and best by dates. I also use the proper lubricant/grease for the light and the o-rings to keep it as water resistant as possible (I use that term because there is almost always a situation where a light will let water or moisture inside). I also use a quality contact cleaner and then DeOxit Gold to make sure the contacts on the light and the batteries are as clean and good as possible and I let those chemicals dry completely (minimum of five minutes drying time) before I reassemble the light.


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## easilyled (Oct 10, 2011)

If the XM-L is driven at 2.8A+ for many hours continuously, its going to be difficult to conduct all the heat away. At this current level, the OTF lumens may be 700 initially but they would probably not stay that way for very long because as the led heats up, its output decreases and ultimately its lifetime is adversely affected.

However drive the XM-L at 1.4A and the OTF lumens of about 400 will probably be rock solid for a long time continuously with half-decent heat-sinking. I'm sure that 400 lumens is more than enough for caving.

McGizmo's Makai light with the 2-cell XM-L L.E drives the XM-L at roughly 1.4A and this is the hardest driven of any of McGizmo's lights. This is one of the reasons that they are so reliable. I suggest that instead of buying 10 Fenix lights, just buy a Makai with 2-cell XM-L L.E instead.


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## i8mtm (Oct 10, 2011)

For the OP's quest for a tough, durable light that can put out the lumens and be under $400, why not try a Malkoff Wildcat?

It will give you the "Wall of Light" you are looking for and they seem very tough. I have one of the older 4-LED Wildcat's with an MD3 body. I have never abused it, but it exudes quality and I think it would hold up well. I paid a bit under $200.

If you want long throw, you could go with the Malkoff "Hound Dog."

I think this is an interesting topic, because it is true that very few people actually put their lights through a "torture-test" or do long-term burn-time testing with lumen measurements, etc. to see if the light really meets the manufacturers claims.

The situation is similar in firearms. The manufacturers know that most people buy a gun, practice every now and then and then put the gun away in a safe or a nightstand. Few problems show up. However, if you get into IDPA competition, or "Run-N-Gun" marches *and* devote lots of time and ammo to practice, you will see lesser guns start to fall apart. 

Even quality guns will start breaking if you are shooting a bunch and don't change out the springs, keep well lubed, etc.

I think a lot of people (myself included) buy a light with a lot of lumens and flick it on high for a few minutes to impress our 
friends. We do not try and run them on high for hours on end in 80+ degree temps holding them in gloved hands.

I would like to see more empirical testing, but maybe some lights just are not really made to be run on high for extended times and the manufacturers know only a tiny portion of their customers will use them that way?


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## alpg88 (Oct 10, 2011)

*Re: I killed my 5th light, why me?*

i just noticed, evey light that died, (not sue about iTP) had led on star, i have always though that a star is the weakest link in heat transfer, and now mine, yours, and others dead leds on stars just make that opinion stronger.

imo you will not get a led light that can run on max for entire time, and expect it live long, wont happen, unless the led is either glued or soldered to a heatsink diectly. that is why i love p7, big enough to work with without the star. 

so you should either look for light that has led not on the star, or get a light that has 2x as many lummens you need, and run it on half power. or replace leds (if that is the case), in your lights, leds are not that expencive.


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## Mikeg23 (Oct 11, 2011)

Streamer said:


> My Gosh Man...if you can pick 6 top of the line flashlights and they all go haywire on you....you should hurry out and purchase Lotto Tickets....I mean, what are the ODDS?


 
I hate to sound like a jerk but I don't see any top of the line flashlights in the list... I am not an expert by any stretch an honestly am a bit of a rookie in the LED world but these lights are being built with brightness in mind and therefore running them on high for long periods of time is probably not good for it. Lights that are built for durability first and brightness second will run on high no problem I would start looking at some different brands.


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## Streamer (Oct 11, 2011)

Mikeg23 said:


> *I hate to sound like a jerk *but I don't see any top of the line flashlights in the list... I am not an expert by any stretch an honestly am a bit of a rookie in the LED world but these lights are being built with brightness in mind and therefore running them on high for long periods of time is probably not good for it. Lights that are built for durability first and brightness second will run on high no problem I would start looking at some different brands.



All right Mike. There were four Fenix torches and two ITP's (Olight). None of them came from the Dollar Store.


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## How Goes It (Oct 11, 2011)

Some experts --- help me out here if you would.

Does anyone remember reading in an Elektrolumens thread, on how you could see if all parts of the MC-E LED were lighting up, by using a welder's helmet? Is this safe to do?

And I guess you could assume that if one or more of the four parts of that LED was not lighting up --- well, then you could figure the LED was fried, at least in part, and that's why the reduced output.

Any experts out there know about this way of checking a MC-E LED?
Is this safe?


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## Double_A (Oct 11, 2011)

Jeff, 

Heat and over-voltage will kill any semiconductor, which is what an LED is.

While the manufacturers rate an LED's life expectancy at 50,000 that is under ideal conditions, being underdriven and with very good heat sinking, none of which happen in a flashlight being _over_driven to the max and for extended periods as you do. Many manufactures only rate their LED's for 5000 hour or less, much less.

As with any tool there are homeowner grade products and professional grade products. I would not expect a homeowner grade product to perform as a professional grade specialty product.

There is a reason why Surefire continues to do very well in a world where much cheaper flashlights promise much more.

In your application I would suggest you get a metal Surefire light as a backup to a caving light. Your life is worth buying professional grade products.


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## Double_A (Oct 11, 2011)

Mikeg23 said:


> I hate to sound like a jerk but I don't see any top of the line flashlights in the list... I am not an expert by any stretch an honestly am a bit of a rookie in the LED world but these lights are being built with brightness in mind and therefore running them on high for long periods of time is probably not good for it. Lights that are built for durability first and brightness second will run on high no problem I would start looking at some different brands.




I completely agree.


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## Crenshaw (Oct 11, 2011)

Every single fenix and 4sevens light with multimode I've ever had has it written in the manual to avoid running the list for long periods on max mode for the exact reason that heat will eventually kill the led.

Given that you've been caving and keeping the lights on max the whole time, it's not surprising thats happened. The most useful sugession here has been that you take apart the lights and test the parts for failure. 

Meanwhile, please use your lights on high if you're leaving them on for any amount of time. The high from something like the tk35 is already blinding and more then enough to go by. I use MEDIUM to light up dark rooms at home at night. 

Crenshaw


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## Lou Minescence (Oct 11, 2011)

When the lights are no longer replaced by warranty, disassemble a failed light and test it to find the exact failure. I'm sure someone on CPF who mods lights would help.


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## fnj (Oct 11, 2011)

Mikeg23 said:


> I hate to sound like a jerk but I don't see any top of the line flashlights in the list... I am not an expert by any stretch an honestly am a bit of a rookie in the LED world but these lights are being built with brightness in mind and therefore running them on high for long periods of time is probably not good for it. Lights that are built for durability first and brightness second will run on high no problem I would start looking at some different brands.



That was my impression as well.


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## xul (Oct 11, 2011)

So the heatsinks depend somewhat on thermal inertia to keep the LEDs cool. 
The smaller heatsinks reduce the size and weight.

Maybe it's like welders. If you figure the watts into one when it's 'on', it exceeds the circuit breaker capacity but by the time the CB is ready to trip the arc is extinguished because welding uses a 'low duty cycle'. Thermally activated CB's can take many seconds to trip even at 2x the rated current - it depends on the trip curve.

Thanks for fixing my edit function.


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## andrewnewman (Oct 11, 2011)

I hate to say it but I am not confident we have gotten to the bottom of this. It isn't over voltage if the lights have 6V drivers and the OP was using a single 18650. It could certainly have been a thermal fault resulting in over heating or just running the LEDS too hot but I wonder still.

My only data point (which is admittedly only marginally valuable) is that I got a chance to run 3 of my lights for 5+ hours on full blast (bright as they go) for a 5 day power outage recently. They were a Fenix TK-45 (after 45 minutes it dropped from turbo to high but a single click got it back up to turbo), a Malkoff MD2 with M61 drop in and a Xeno F8V6 XML. In each case I had to swap batteries each evening at least once in each flashlight (I was feeding laptop refugee 18650s to the MD2 and the Xeno) and recharge them all the next day at work (where there was power). So that's 25+ hours on three lights of different design without a single incidence of visible dimming of the LED. The lights were set in a still room tailstanding most of the time. I did move them about periodically and none were too hot to pick up even by the head.


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## jeffkruse (Oct 11, 2011)

First, I am an Electrical Engineer so I know something about electronics. I have built many HID dive lights. LED lights are new to me.

There is no corrosion or oxidation. Ah, test the battery, good one, ha ha. I wish you could by a charger/tester like the LaCross for AA’s for 18650’s.
I have a CBAII but have not tested my 18650’s. My test of the 18650’s is just to put them in another light and use them. I know the voltage won’t go up so if they start at 4.15 they won’t overdrive the light.

I understand if the LED is driven to hard the life will be reduced but how am I supposed to know how hard its driven and how much it can take. There are so many LED’s out there I can’t keep up. Hell, I can’t keep up with the latest flashlights on the market.

That is why I need specific suggestions for a good 18650 light that can be used on high indefinitely. I want over 300 lumens with a price less than $200.

Suggestions with links where I can buy them please!


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## jeffkruse (Oct 11, 2011)

Also, why do the failed lights still work and cycle through there modes properly just way dimmer. There is no browning of the LED.


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## andrewnewman (Oct 11, 2011)

jeffkruse said:


> Also, why do the failed lights still work and cycle through there modes properly just way dimmer. There is no browning of the LED.



Most burnt out LEDs I have seen that were originally white are sort of dim and bluish when illuminated and you can usually see some visible discoloration (yellowish-brown) with the naked eye. So I remain mystified.

The Xeno F8V6 XML is well over 300 lumens well under 100 dollars and a data point of one (me) says it can run on full blast without damage for an extended amount of time. It's decent quality (Fenix-class IMO) and can take a fair bit of abuse (mine is totally beat up from dropping on asphalt and cement). The bezel is SS so it helps protect the lens from breakage. As a bonus it also has protection circuitry built in for 18650s to avoid over discharge with unprotected batteries. Tailcap rubber boot and o-ring in the bezel are both GITD.


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## Darvis (Oct 11, 2011)

andrewnewman said:


> I hate to say it but I am not confident we have gotten to the bottom of this.



And probably never will. For all the great testing members do here on CPF, this thread has made me realize our tests are typically, if not always, limited to the specs of a light out of the box; Things like runtime on the various modes, output, and occasionally, duribility ala the "glock" test (freezing, dropping, throwing...)

I know cost and time are factors, but come to think of it, I've not really seen anyone compile or do long term runtime tests on high. I'm sure it's possible with a bench top power supply and some serious cash!!! 

Can anyone think of any manufaturers that have run these types of tests and published them? It would be great data. An no, I'm not volunterring to pioneer thse tests either... Just wondering.

But the OP has some good anecdotal experience and raises, at least, some good questions about this type of extended use. I think we can speculate based on what we know about driving LEDS at various mah levels, good heat sinking, light that fit this description that some of us have used for extended periods of time, etc. I think the Star mounting vs. direct to heat-sinking is an interesting observation.

On an semi-related note, I did just upgrade all of my house lighting to LED, most of those light will run for hours at a time on their highest level. It will be interesting to see if they last!


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## andrewnewman (Oct 11, 2011)

Darvis said:


> And probably never will. For all the great testing members do here on CPF, this thread has made me realize our tests are typically, if not always, limited to the specs of a light out of the box; Things like runtime on the various modes, output, and occasionally, duribility ala the "glock" test (freezing, dropping, throwing...)
> 
> I know cost and time are factors, but come to think of it, I've not really seen anyone compile or do long term runtime tests on high. I'm sure it's possible with a bench top power supply and some serious cash!!!
> 
> ...



I would love to see some of these tests conducted! In general, I usually run new lights through 2 full sets of batteries (or recharge cycles) right out of the package to weed out infant mortality during the return period window. I did that with a new Jetbeam PA-40 recently and it was also easy to pick up by the head after running for several hours on the highest setting.


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## psychbeat (Oct 11, 2011)

Buy a solarforce L2P or bored surefire and a potted Nailbender drop-in. Use the supplied copper tape. 
Under 100$ (with the L2P) done. 

I'd get the neutral XM-L or XP-G. 

I run mine on max at least once or twice a week til close to or at cutoff. 
Mine is 2.8a dual XP-G neutral. 
No problems so far in almost a year. 
It gets shaken quite a bit on my DH mtn bike handle bars. 
But I also use it as an area light when trail building.


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## 2100 (Oct 11, 2011)

jeffkruse said:


> That is why I need specific suggestions for a good 18650 light that can be used on high indefinitely. I want over 300 lumens with a price less than $200.
> 
> Suggestions with links where I can buy them please!



There are a lot of points made.... 

Allow me to make a practical one.

(1) You need lumens and efficiency. Solution, triple XM-L.
(2) Triple XM-L can give you well over 2000 lumens OTF but you can only use it in bursts, even the SR92/TK70 i'd not recommend you to gun it past 20 mins unless you are in a very cold environment + wind. Issue is not only the LEDs but also the driver electronics (most do not have excellent heatsinking).
(3) Triple XM-Ls when in 600lm mode have crazy efficiency. You get excellent runtime and there is literally no heat even with 600 lumens. 
(4) Beam profile is wide enough for caving work i guess, but has enough throw for your 100-200ft distance use. 
I understand that mud (esp if it's really the dark type) really soaks up the lumens, even with dark adapted eyes it would not be easy with 300 lumens. 

Solution, Jetbeam RRT-3 XM-L. Unfortunately the cheapest i have seen is usd275 shipped worldwide, but it does come with 3 x 18650s. 

BTW, the moderation is extremely extremely strict here, we are not supposed to post links and I have been banned once for doing that. So can't do dude....


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## RedForest UK (Oct 11, 2011)

I seriously doubt that it is the LEDs which are failing. They are rated to 50,000 hours I believe at full stated max current, they end the test when output has degraded to 75%, obviously due to the time involved full tests are often not completed and values given are extrapolations. But they should last way beyond a few thousand hours.

Remember that LEDs aren't primarily designed for flashlight applications, but fixed lighting ones where they will be on for much longer periods. There is also much less active/air cooling for still lights set in place. 

For example, I had 4 of dealextreme's 3x warm LED GU10 light bulbs, the LEDs used were generic ones not rated anywhere near a long as the Cree ones used in these high performance lights. They were also driven pretty hard; the light bulbs themselves if left on for more than an hour would be almost too hot to touch for more than a second. However, one time I went on holiday I left two of them on overlooking the garden to deter burglars, for the whole 7 days I was gone. That is over 150 hours of solid use, all the while at very high temperatures. But even after this, when I got back the two that had been left on showed no discernable difference from the two that had been 'rested' the whole time.

I now use the great 4x warm Cree XP-E versions from DX instead of the original cheaper ones (the colour and output is much better, and beam profile and heat management are also better). But even the cheapo generic LEDs survived for 150 hours solid, on top of about 6 months use at between 3 and 6 hours a night. I really don't think you have an LED degredation issue.

Electronics on the other hand are much less hard-wearing, and can die after around 1000 hours, they are only as strong as the least durable component in the circuit. I think that is probably where the issue is.


So, I recommend you look for a good high output light which runs Direct Drive off of either 3x Ni-mh cells or a single Li-ion 18650. You should get decently flat discharge/output. 

The manafont XM-L drop-in is a great example of this on a budget, and is very well made and reliable for it's low price tag. However this would require some work to make it reliable enough to run for long-periods, with a decent amount of effort involved to make a proper thermal path to the body of the light.

Other options in a ready to use package could be found with some Peak models or from Elektrolumens, both brands also with a reputation for durability.


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## Double_A (Oct 11, 2011)

jeffkruse said:


> First, I am an Electrical Engineer so I know something about electronics. I have built many HID dive lights. LED lights are new to me.
> 
> There is no corrosion or oxidation. Ah, test the battery, good one, ha ha. I wish you could by a charger/tester like the LaCross for AA’s for 18650’s.
> I have a CBAII but have not tested my 18650’s. My test of the 18650’s is just to put them in another light and use them. I know the voltage won’t go up so if they start at 4.15 they won’t overdrive the light.
> ...



Suggestions with links where I can buy them please!

Jeff buy a light specifically designed for caving, it will have mechanical and electrical construction robust enough for what you want it to do. As a back-up buy a Surefire Light and as a second back-up buy a Peak light. Only Surefire and Peak lights I'm familiar with are robustly built and conservatively rated and I trust to be back-up for the specific category (Caving) of light for your function.

ETA: Buy a caving magazine and find out what lights these people are happy with

Some unorganized thoughts for others,

In 25 years I've bought dozen of lights for professional use in Safety, Security & Haz Mat response use. Matter of fact when Surefire came out with the E2e, I bought ten of them for my crew and we ditched 3-D Maglights. The Surefires were three times the price of the Maglights and they performed accordingly. Special tools for special applications.

Reading a manufacturers spec sheet on an LED would be a good way to start. My former company put out spec sheets, product suggestions and sample circuits on very part we made (We made analog and mix-signal ICs, including LED driver IC's).

These LED's are like car engines in a car. While you can drive a car at 120mph, can you drive it at 120 mph until it's tank runs dry? and can you do that day after day?

Maybe the engine manufacture says the engine can do it, but will the vehicle manufacturer build a car that can deal with the stress? Great engine, but cheap suspension, steering, body etc. You get my point. If it was designed for an average person I'd bet my life it cannot, if the vehicle and engine were specifically designed to run at redline speed for hours and days on end, then it better perform, but how much are you going to pay for that engine/vehicle combination? Ten times, Twenty times a normal consumer car?

So if a Flashlight wasn't designed for that kind of use it probably won't hold up. First thing I do with a light and look at how the battery makes electrical contact. Is the battery contact spring, light and flimsy? how about the opposite end, is it just a circular PC board trace? Normally it is that tells me it's a homeowner grade product.

Most flashlights people buy here buy the lights you've had fail, they are perfect for them. They use them in a manner which the manufacturer expects an average homeowner would.


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## 2100 (Oct 11, 2011)

Double_A, those are good points. I reckon for caving you'd expect the light to be banged up pretty good as well. 

I am not sure how the RRT-3 stands up to abuse, but the RRT-2 stress tests are pretty impressive. I haven't put it to tests in the field, but actually we got this to be used in the "jungle" and we are expecting it to be dropped from as high as 40 metres but landing on soft ground. We used HIDs but never expected the drops. "no light" in the jungle is a big problem! So this would be the backup, naturally this needs to be reliable. We need the 4000+ lumens because it's for patrol (for private property). Actually we are also using them in caves as secondary, but rather man-made caves for birds nest. If any observation is to be made in such lumens soaking surfaces that are range several as far as 100-200 feet , i'd go as far to say that you might need bursts of 1000 lumens even.

It seems that the failures are not due to mechanical but rather something else, driver electronics or LEDs but it is likely to be due to heat. 

I am not familar with Surefire/Peak as you've mentioned, but according to the OP's requirements is there something that is less than $200 (ok put it as less than $300 just to expand the selection), can do 400-600 lumens for hrs at the time without heat failure (to be comfortably over his requirement)? The RRT-3 has 3 x 18650, but lets assume that you are allowed to change out the batteries.

Caving light systems (LED) do hover ard the 1000 lumen mark. Stollman does light up his caves with the BLF192, a dual 100W HID portable carry handle lantern. Of coz I think one already has the headlamp as the primary close-range illiumination source....i think the usual recommendation is actually 3 lights.

PS. I think he mentioned that he uses gloves as well, thus insulating the lights somewhat.


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## How Goes It (Oct 11, 2011)

How Goes It said:


> Some experts --- help me out here if you would.
> 
> Does anyone remember reading in an Elektrolumens thread, on how you could see if all parts of the MC-E LED were lighting up, by using a welder's helmet? Is this safe to do?
> 
> ...



Okay --- I found the post over at the ElektroLumens section.

It's post number 204 at the below URL

http://www.cpfmarketplace.com/mp/sh...ack-Anodized&p=2451646&viewfull=1#post2451646

Now I bring all this up, because the ElektroLumens EDC MCE and the TK30 both use an MC-E LED.

Wayne, the ElektroLumens guy, says this is a way to check the MC-E LED in his flashlight.

So if an LED isn't as bright ----- the reason might be because part of the LED is burnt out.
To loosely quote Wayne --- one of the 4 dies in that LED, may have died.

But again I ask --- is this safe to do?


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## xul (Oct 11, 2011)

RedForest UK said:


> I seriously doubt that it is the LEDs which are failing.


You can check an LED with a car battery, power resistors and a DVM by comparing your measurements to the spec. sheet.


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## jeffkruse (Oct 11, 2011)

Let me try to respond to the posts from my last post.

It should be easy enough to “life” test these. Take a few blem units and hook them up to a 4V PS. Check on them once or twice a day for a few weeks. I would be happy with only 1000 hours of life. That’s how long my $200 24W HID scuba diving bulb lasts.

I don’t want to be modding any lights. I want to buy one, put in a 18650 and go caving. Biking is much much harder on the lights then I am.

I would love a single 18650 600lumen light. However, I want the smallest head that can give me at least 1000 hours of life.

I read the TOS and paragraphs 5 and 6. I don’t think they prohibit links especially since I asked for them. Links would help since finding the right light is a lot of work.

Cave lights are all headlamps. I want a handheld light. I use a headlamp but really like a small light in my hand.


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## How Goes It (Oct 11, 2011)

jeffkruse said:


> Biking is much much harder on the lights then I am.



Yes and no.

Regarding shock, maybe some or a number of bike lights might be more durable.
But as to heat, I'm not so sure that all or even the majority of bike lights are more forgiving.

The instructions for my old Nightsun Team Max --- Never operate on low beam for more than 20 minutes without moving, and never operate for more than 3 minutes on high without moving.

Granted this is not an LED. But some of those high powered LED bike lights may have the same kind or similar instructions.

So, again --- it may be an issue of heat and drawing off that heat.

As with the ElektroLumens EDC MCE, it is mentioned on how the bare hand draws off some of the heat.
In your case, you mentioned using gloves?
These gloves may actually exacerbate the problem in that they act more like an insulator, holding the heat into the light, and causing a kind of thermal run away (under 85 degree ambient temps.), rather than acting as a heat sink, as is with the bare hand.

Meaning --- I could see wearing a glove with a higher powered light, run on high for long periods, possibly when it is cold or cooler. But the combo of 85 degree ambient on top of using gloves, may be what puts your LEDs over the top enough to cause one or more of the dies in this 4 die LED to fail.


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## jeffkruse (Oct 11, 2011)

FORGET the gloves! I don't hold the light by the head and a lot of the time I am not holding the light at all. When my PD31 went bad it was wet (dry on the inside).


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## How Goes It (Oct 11, 2011)

And the ElektroLumens lights are also not being held by the head either.
You could really fry your hand if you did.
The body of the flashlight is acting in part, as a heat sink.

But hey, heat may not have anything to do with it.

Then again --- there apparently are ways of seeing if the LED is partly fried or not -- in which case I would think, the problem could be heat.

Just putting it out there --- since you are still bewildered as to why things failed --- but I'll dispense with the heat talk.

Good luck.


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## dosei-45 (Oct 11, 2011)

jeffkruse said:


> I need specific suggestions for a good 18650 light that can be used on high indefinitely. I want over 300 lumens with a price less than $200.
> 
> Suggestions with links where I can buy them please!



Armytek Predator???
http://armytek.com/armytek_predator.html

Browsing thru websites that cater to the spelunker, what you want does not exist. You can have less lumens and meet your price-point, or spend more and get the lumens you want.

Seems to me that your primary light should be a headlamp. Ideally, it should be a helmet mounted light (since a helmet is generally considered mandatory equipment when caving). Seems this one is one of the top beasts for the caving crowd:
http://viperlights.com/index.php



If it were me...I'd be saving up for:
http://viperlights.com/index.php
A Spark SD6-500CW XM-L or a Spark ST6-500CW XM-L
A Surefire host bored for a 18650, with a Malkoff "Low" output drop-in
...and whatever my EDC light(s) are at the time.

IMHO...caving is more abusive and places a much greater dependence on a light than combat, so my primary light(s) would be caving specific or combat proven...preferable caving specific (i.e., built specifically for caving and regarded as the best). As for "combat" lights that I would trust to that level...Surefire is the only one.


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## jupello (Oct 11, 2011)

RedForest UK said:


> I seriously doubt that it is the LEDs which are failing. *They are rated to 50,000 hours I believe at full stated max current*, they end the test when output has degraded to 75%, obviously due to the time involved full tests are often not completed and values given are extrapolations. But they should last way beyond a few thousand hours.



Not true.

For example Cree XP-E: 
-Max current is 1000 mA
-Output is around 70% of the original after 50 000 hours, IF the drive current has been under 700 mA AND the temperature of the LED has not gone over 135 Celsius at any time.

Generally, they seem to recommend using under 2/3 of the maximum drive current under good cooling conditions to maintain good lifetime for the LED. And even lower with weak thermal path or high ambient temperature.
Cree's datasheets can be found from http://www.cree.com/products/xlamp_docs.asp


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## chmsam (Oct 11, 2011)

If it's an overheating problem while you're caving (generally a cool to downright cold environment) the problem is from the heat generated inside the light of course. However, if the LED's are indeed discoloring and that in turn is the cause of the perceived dimming then overheating would be the first thing I would suspect. As to the problem of a light getting wet, a cave is usually a wet environment, correct? However a light does not have to be really wet inside to fail. Moisture that might not be easily seen could cause a failure especially if the light is exposed to moisture over time.

My best guess from very limited knowledge of caving would be that a multi-LED or an HID setup would be far better if you want that many lumens from a single source. You know that usually the trade off for large amounts of light wanted for both throw and flood is the weight of the power supply. Multiple lights might be a better comprimise than one "uber-light." If that is anywhere near a possible consideration you could end up with better preparedness (the odds of mulitple lights failing is always in your favor more than just one) and still probably end up with a lower total weight. Would you consider a combo of lantern(s) and lights -- maybe go at the problem from more of an optical approach than an electrical engineering one?


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## TyJo (Oct 11, 2011)

How Goes It said:


> Okay --- I found the post over at the ElektroLumens section.
> 
> It's post number 204 at the below URL
> 
> ...


 I don't see why it wouldn't be safe with the welders helmet. Another method is to shine the light close to the surface of water at an angle (sink, tub, pool, etc.). You can view the emitters reflection in the water like a mirror only not as intense, but still pretty bright.


dosei-45 said:


> Armytek Predator???


I love my Predator but they are new. A few lights had hiccups, but those issues seemed to be taken care of in production and the customer service was great with the defective lights. There is an impressive video of the light being abused, but I'd make sure I'd have some backups obviously, especially with a new brand and new light.


I still have a hard time believing the build of the TK30 is to blame for the dimming, whether it be the LED, driver, or other component over/heating or failing. I'm assuming a lot of TK30s were sold and I would guess many more TK40s were sold, both used the MCE. I realize few people run their lights on high this often or for as long as the OP but I would still think there are plenty that have ran their TK30/TK40 this hard and the issue would have came up. We aren't talking about 1000s of hours, the OP said 10 hours.


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## alpg88 (Oct 11, 2011)

put any cd\dvd over the light buissnes end, when it is on, and you'll see dies without damaging your eyes


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## Bimmerboy (Oct 12, 2011)

Streamlight Survivor LED

Should be quite hard to kill one, and beam intensity is excellent... good for lighting up a patch of photon absorbing mud and bat guano a hundred feet or more.

A Surefire 6P or 9P w/Malkoff (especially an older M60, if you can snag one at CPFMP... more throw than the M61) would be a super durable backup.

Try 'em both, and let us know if you manage to fry either one!


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## jeffkruse (Oct 14, 2011)

*Re: Why do my LED lights keep dying? Update*

I was about to put my PD31 into a box and send it back. I decided to give it one last try. I played with it for a few minutes switching between modes over and over again. 

Then, all of a sudden it was in high mode again! I cycled through the modes again and everything seems normal. I’d swear this wasn’t a user error but I don’t know what to think now.

Is it possible for the UI to crash? It seems to be working fine now.


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## RedForest UK (Oct 14, 2011)

*Re: Why do my LED lights keep dying? Update*

Could it be the tailcap got loose? Have you tried tightening the ring inside it?

Maybe you somehow triggered low voltage protection?


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## Got Lumens? (Oct 16, 2011)

*Re: Why do my LED lights keep dying? Update*

Along the same lines as RedForest UK was saying, try taking the tailcap switch apart fully and lightly scuff parts that mate together, especially the alluminum to Gold on the switches PCB and reassemble with Deoxit. It sounds exactly like how a High Resistance DC open acts. I had this happen on a problematic 47s tail switch, and has been fine since. More testing. Very interesting thread.
GL


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## yifu (Oct 16, 2011)

*Re: Why do my LED lights keep dying? Update*

Wow that really must be very weird. What type of batteries/chargers have you been using. I never had any light of any price range fail on me, even one of those 2 dollar keychain lights dropped into a sink still works. Probably try a surefire? A G2X pro should do the trick.. A good 18650 light with 300+ lumen output would be the SC600. Read the Zebralight torture thread here http://www.candlepowerforums.com/vb/showthread.php?321619-Zebralight-Torture-Test
A zebralight was dropped, heated to 200+ degrees, frozen in ice with the battery in it and it continued to work... If you manage to break that one you are either, trolling, living in a place with random power spikes, or i dont know


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## How Goes It (Oct 16, 2011)

After reading about how you kept clicking your switch and it finally worked, it does sound like it could be a contact issue as Got Lumens talked about.

MAYBE, there is literally something in the air in those bat guano encrusted caves. Maybe ammonia or something --- that causes the contacts to foul. But this is also premised on the idea that those lights are opened up --- say for a battery change - while in the cave.

Then again --- if it was something in the air (a big guess on my part) --- that makes me wonder what it would be like to breathe that stuff in.


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## matrixshaman (Oct 16, 2011)

I'd suggest you buy a 120 HDS for $99 or a 140 HDS for $124 and once you see how bullet proof these are you'll want a Rotary or one of the higher output ones. Just take a look at what this light on Henry's main page has been through and it's still working fine: www.ralights.com Despite being a caver I bet none of your lights are that beat up looking. Henry BTW is a serious caver and he designs and builds the HDS lights to be reliable in that environment.


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## 2100 (Oct 17, 2011)

So....seriously after reading all the threads and the PD31 coming back alive again....i think the problem is still "hidden", and till we find that any new lights purchased may still have issue. A lot of variables unknown to us who are trying to help.


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## Dude Dudeson (Oct 17, 2011)

I know a guy who kills flashlights via his own soul's presence. He went through FOUR Surefires (three of which were warranty replacements) and then Surefire decided they were done with him. He's almost 80 years old now, and has had this problem his whole life.

The only "rational" explanation is he's simply cursed there. I could write a book about "curses" but only those who've had them would believe a word of it....


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## ampdude (Oct 17, 2011)

Cheap lights with cheap electronics, thin threads, and cheap circuit board contacts. I don't know why anyone expects lights like these to last.


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## Dude Dudeson (Oct 17, 2011)

ampdude said:


> Cheap lights with cheap electronics, thin threads, and cheap circuit board contacts. I don't know why anyone expects lights like these to last.



I don't know why people think spending a ton of money on ONE tool is some guarantee against failure either.

"Two is One, One is None".

Already knew this doctrine before visiting CPF, and CPF has only reinforced my belief in it.


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## Got Lumens? (Oct 17, 2011)

Well there is always glowsticks . . . 
No batteries, No electronics, and No light either folks . . .

I would have suggested Fire on a stick, but that doesn't play well with caves, water, or explosive gasses. . .


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## jeffkruse (Oct 17, 2011)

*Re: Why do my LED lights keep dying? Update*

After getting the light to work I took it caving with me Saturday. It worked fine but after about 2 hours it did switch back into that funky dim mode. When it switched the light was not being jostled and the head was barely warm. I was able to get it back to normal with a few mode changes.

The light head barley even gets warm when I use it on full power.

When I try to I can’t get it into this funky dim mode.


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## Outdoorsman5 (Oct 17, 2011)

*Re: Why do my LED lights keep dying? Update*

I know a lady that can't wear watches. She says they always just stop working after a short time. After years of this her husband decided to get her an expensive watch, but it too quit working after very little use. She says it's been this way her whole life, and has just given up. I have to admit that I didn't believe her, but after reading this thread maybe there's something to it.


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## Th232 (Oct 17, 2011)

*Re: Why do my LED lights keep dying? Update*



jeffkruse said:


> After getting the light to work I took it caving with me Saturday. It worked fine but after about 2 hours it did switch back into that funky dim mode. When it switched the light was not being jostled and the head was barely warm. I was able to get it back to normal with a few mode changes.
> 
> The light head barley even gets warm when I use it on full power.
> 
> When I try to I can’t get it into this funky dim mode.



This doesn't sound right. So during those first two hours it was constantly on and didn't get very warm at all? If it's on max then the heat has to go somewhere, and if it's not going outside via the casing, it sounds like it's staying inside..


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## dosei-45 (Oct 17, 2011)

*Re: Why do my LED lights keep dying? Update*



jeffkruse said:


> After getting the light to work I took it caving with me Saturday. It worked fine but after about 2 hours it did switch back into that funky dim mode. When it switched the light was not being jostled and the head was barely warm. I was able to get it back to normal with a few mode changes.
> 
> The light head barley even gets warm when I use it on full power.
> 
> When I try to I can’t get it into this funky dim mode.



Have you tried just using it at "High" instead of "Turbo". As several other Fenix owners have noted, the Fenix owners manual for their lights does not recommend using the light at "Turbo" for extended periods of time. I recall the manual for my TK12 R5 saying something along those lines, but I cannot find the manual now to confirm it. Have you read thru the manual and does it have any such statement?


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## ampdude (Oct 17, 2011)

ITPython said:


> My bet is that since you are running them on Max all the time, they are overheating and slowly dieing. Diodes do NOT like heat. One of my previous hobbies was lasers, and the biggest limiting factor with a powerful laser was the duty-cycle. Even if you had a good heat-sink the duty-cycle was not unlimited and you still had to be careful as to not overheat the diode. I am willing to bet LED's are not much different, they may be more tolerant of heat than a uber sensitive laser diode, but that doesn't make them invulnerable to heat.
> 
> Flashlights get very hot when used in max mode (usually borderline too hot to touch), and I think people underestimate the level of damage their lights LED may get from running them in max with no adequate dissipation for all that heat. They just assume the light can handle it because there is no mention of warning by any of the manufactures about duty-cycles. This would explain your output drop, as the same exact thing happens to laser diodes when you overheat them.
> 
> If you don't want your lights to keep dying on you, keep them cool when using in max mode! Perhaps you could have some large chunks of aluminum machined to fit the lights for added heat dissipation, or you could just run the lights in high rather than max.



Aside from the cheap lights he is using, I think you're onto something there as well. In my experience diodes don't like heat (or too much voltage either). If he's using these lights as headlamps, they are not getting any heatsinking by being held in the hand since they are headlamps. A lot of the powerful LED lights should always be held in a closed fist when run on highest setting for maximum heatsinking. Same is true with powerful lithium incans, to protect the battery temperature.


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## TyJo (Oct 18, 2011)

I wouldn't call Fenix cheap lights, I consider Fenix a quality brand. Jeffkruse, Did you have the PD31 head screwed down real tight? Were you using the PD31 in Turbo mode (Turbo, Strobe) or High Mode (Low, Med, High, SOS)? When your PD31 is dimming has it been running for an hour or 2 (the batteries could be at a low voltage)?


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## jeffkruse (Oct 18, 2011)

The head was on tight and it *was not hot*. It was on it's brightest mode. The batteries continued to last for at least 30 more minutes, thats when I left the cave.


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## jeffkruse (Oct 18, 2011)

*Re: Why do my LED lights keep dying? Update*

On a side note my "repaired" warranty replacement package for my TK31 was stolen from inside my gate. :scowl: I signed up for a PO box this morning. I don’t need any more of my lights being stolen. 

Time to get a Zebra light SC600. I hope it will last on full power.


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## fisk-king (Oct 18, 2011)

matrixshaman said:


> I'd suggest you buy a 120 HDS for $99 or a 140 HDS for $124 and once you see how bullet proof these are you'll want a Rotary or one of the higher output ones. Just take a look at what this light on Henry's main page has been through and it's still working fine: www.ralights.com Despite being a caver I bet none of your lights are that beat up looking. Henry BTW is a serious caver and he designs and builds the HDS lights to be reliable in that environment.



+10


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## Scubie67 (Oct 18, 2011)

What do your friends you go caving with use and do they have similar and as many problems with lights failing is a good question if anyone hasn't asked before? If they are caving in the same conditions and not having as many failures with their lights it may not be the lights,maybe they don't run their lights on high all the time.Just asking


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## Th232 (Oct 18, 2011)

jeffkruse said:


> The head was on tight and it *was not hot*. It was on it's brightest mode. The batteries continued to last for at least 30 more minutes, thats when I left the cave.



This still doesn't add up. I'm sorry if I haven't noticed this, but I haven't seen an answer to the question TyJo and I asked: Was it running constantly for those two hours? If the answer is yes...

On its brightest mode, let's assume that the LED is drawing 1.1 A (I think it might be drawing more). I vs Vf chart for an XP-G says Vf = ~3.35 V. So call it 3.7 W. On its brightest mode it must be drawing 3.3 W, this is non-negotiable.

It must be dissipating some of that 3.7 W, let's say it's 3 W. The number may be negotiable, but it is definitely dissipating a fair amount of heat.

That heat has to go somewhere. You're an elec eng, have you ever seen an IC or something small dissipate 3 W and not get hot? Maybe even a linear regulator in a TO-220 package with one of those little finned heatsinks.

Personally, I'd recommend you get a multimeter and test the tailcap current in your home. Sit there with it to see if the light gets hot or the tailcap current changes. Running on max (and thus dissipating 3 W) and not getting hot (with this form factor and no active cooling) are almost entirely mutually exclusive. I see three scenarios:
* One, it's getting hot and you can't feel heat. This is pretty much absurd.
* Two, the light's been slowly dimming (does the PD31 have thermal protection?) and you haven't been noticing it because it's a gradual process. I've been guilty of this a couple of times. How did you know that it was on maximum? Did you just trust your eyesight or did you compare it to a working torch with fresh batteries?
* Three, there's some strange condition you haven't noticed. Doing this in your home should remove that condition.

If it's the heat, I'd say the circuits are getting damaged before the LED, based on its apparent recovery.


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## jeffkruse (Oct 18, 2011)

“What do others carry?” HA, they don’t have a lot of light. I have seen some real dim lights. Sometimes I hand them one of my hand helds and they are amazed. They want one but won’t spend the money to get the light and deal with 18650’s. Cavers are cheap and this is Puerto Rico. No one carries a hand held. Hell, they still use disposable AA’s till they are completely dead. Never mind trying to get them to use Enloops.

A lot of people use the Apex headlamp and that is what I use as well. There are a few Sten users. Some still use Carbide. 

I don’t understand why people tell me 100, 200, 300 or whatever lumens are enough. For that matter you could use just 50 lumens. THAT’S NOT THE POINT. If a small flashlight was 2000 lumens with a decent runtime that is what I would want. As long as I don’t blind the other members of my party then it’s ok.

The RAlights I see only go to 200 lumens? I want at least 300 or more.


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## Th232 (Oct 18, 2011)

jeffkruse said:


> I don’t understand why people tell me 100, 200, 300 or whatever lumens are enough. For that matter you could use just 50 lumens. THAT’S NOT THE POINT. If a small flashlight was 2000 lumens with a decent runtime that is what I would want. As long as I don’t blind the other members of my party then it’s ok.
> 
> The RAlights I see only go to 200 lumens? I want at least 300 or more.



I have a hypothetical: If I told you that all the 1x18650/2xCR123 flashlights that emitted 300 lumens or more could do so for the entire runtime of the battery but at the expense of having a terribly short lifespan, say, 100 hours, would you then lower your expectations? Because with the track history of the lights you've had going through these conditions, that may seem like the sensible thing to do until further advances in LED technology come along.


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## jeffkruse (Oct 18, 2011)

Th232 said:


> I have a hypothetical: If I told you that all the 1x18650/2xCR123 flashlights that emitted 300 lumens or more could do so for the entire runtime of the battery but at the expense of having a terribly short lifespan, say, 100 hours, would you then lower your expectations? Because with the track history of the lights you've had going through these conditions, that may seem like the sensible thing to do until further advances in LED technology come along.



1000 hours OK, 100 hours not ok. The only light that got hot was the TK30 and that was just stolen from me. The other lights don't get very warm on the outside. 

It might be my history but I still expect more. I'll factor in a 10X reduction in avertised life for my expectations. I would expect to loose, flood, or have something much better come out before they should die on me.


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## RedForest UK (Oct 18, 2011)

Firstly, Fenix lights aren't cheap. Anyone who says so is either deluded as to the financial state of the majority of the world's population or just a plain arrogant snob. Fenix lights are not top of the line, but are very high quality performance lights. Please bear in mind however that when manufacturers state 'LED burn life 50,000 hours' they really do mean just the led, the electronics should last a while but I wouldn't expect more than 10,000 hours at full power..

That said, I don't think either is the issue here. If you run the light on Max for 2 hours before it dims then it seems likely that all you are getting is low-voltage protection kicking in from the cell. What batteries are you using? Do you have a multimeter to test voltage?

Cell voltage will drop-under load to below the voltage protection threshold, and while you shouldn't really use further after that point for the good of the batteries long term life it will be possible to switch back to high mode again once the cell voltage 'recovers' having been in a lower mode for a while.


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## Th232 (Oct 18, 2011)

Out of curiosity, what temperature do you mean by "very warm"? 50 deg C, 70, 90?

Also, RedForest brings up a good point. When you've had the PD31 drop to low, have you just been trying it again with the same battery, or a fresh one? I'd assumed that you'd been doing it with a freshly charged one.


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## Bimmerboy (Oct 19, 2011)

Jeff - this thread is getting weird. What exactly do you want?


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## jeffkruse (Oct 19, 2011)

Bimmerboy said:


> Jeff - this thread is getting weird. What exactly do you want?



The only weird part of this thread is when people think they (or I) have some kind of energy field that kills electronic devices J.

What I want is a light that will work as advertised. Actually I am ok with a 10X less lifespan!

When I say warm I mean about 45C/115F. I can squeeze the light head with my bare hand indefinitely.


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## Got Lumens? (Oct 19, 2011)

jeffkruse said:


> The only weird part of this thread is when people think they (or I) have some kind of energy field that kills electronic devices J.
> 
> What I want is a light that will work as advertised. Actually I am ok with a 10X less lifespan!
> 
> When I say warm I mean about 45C/115F. I can squeeze the light head with my bare hand indefinitely.


You can disprove that field theory by swapping lights with another member of the team. If they use it the same as you do, Max, under the same conditions, then it should fail while they are using it also.


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## Th232 (Oct 19, 2011)

I really think you should do some power tests on that PD31 (and others if you still have them) if it's on max for more than a couple of minutes and isn't warm. Still doesn't sound right to me.


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## alpg88 (Oct 19, 2011)

Got Lumens? said:


> You can disprove that field theory by swapping lights with another member of the team. If they use it the same as you do, Max, under the same conditions, then it should fail while they are using it also.



idk, if it turns out right, he'll kill someone elses light.


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## Sparky's Magic (Oct 20, 2011)

Sparky's Magic said:


> Perhaps it's time to go down the HDS path with an MD3 - XM-L Hi-Low as a back up. Neither of these lights will let you down nor will they over heat: The back-up XM-L will light up any spectacular large formations, caverns, lakes etc. brilliantly.



I say again...


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## leon2245 (Oct 20, 2011)

jeffkruse said:


> The only weird part of this thread is when people think they (or I) have some kind of energy field that kills electronic devices J.
> 
> What I want is a light that will work as advertised. Actually I am ok with a 10X less lifespan!
> 
> When I say warm I mean about 45C/115F. I can squeeze the light head with my bare hand indefinitely.





Can you tell us the specific output level you're seeking? Because you'll have to go with a light whose max output is a bit above your target target level (& big enough to continuously dissipate heat) so that its next level down can be used nonstop for the duration of its runtime.

If there is no specific output level you have in mind, & it's more out of principle that you don't like the idea of having to run your light at anything other than max for longevity, try something like the m6lt? Really bright, & with only one level it's obviously designed to run maxed out as long as you need it (maybe pick up a couple of extra battery carriers preloaded with lithium primaries for extended runtime). And don't worry if your personal magnetic aura somehow manages to kill this one- surefire will have your back. I think it should be good for whatever you throw at it though.


tldr:
1. Buy a bigger, brighter light than you need, then run it at a lower setting, or
2. Increase your budget, or
3. Lower your expectations for longevity even further.


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## jeffkruse (Oct 20, 2011)

I am looking at the Zebra light SC600W. The size is a little big but OK (the size of the PD31 is perfect).

750 lumens for 5 minutes and 500 lumens for 2 hours. If this light can run at 500 lumens for a few thousand hours I will be very happy. If it dies in 100 hours I will be upset. 

I have expectations of using this light once a week for a few years (52 x 3 years x 4hours = 624 hours)

I think 20% of you will say I can’t do this and the light will die just like my others. But, I think the other 80% will think this is reasonable?


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## easilyled (Oct 20, 2011)

jeffkruse said:


> I am looking at the Zebra light SC600W. The size is a little big but OK (the size of the PD31 is perfect).
> 
> 750 lumens for 5 minutes and 500 lumens for 2 hours. If this light can run at 500 lumens for a few thousand hours I will be very happy. If it dies in 100 hours I will be upset.
> 
> ...



What about buying 2 of them and rotating? That might help to prolong the life of each one.


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## 3Diver (Oct 20, 2011)

From all the experiences of making cheap diving torchs for snorkeling, after frying a few LEDs in different torches i finally figured out what i did wrong(same symptoms works great then pretty much permanently dim and flickering).

*Cause of the Problem was silicone used, do no ever use silicone that has the smell of vinegar or smell at all, it will fry the led.
*Cheaper lights also has lousy contacts when i greased the threads heavily, have also found light flickering dimming not turning to full mode.


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## dosei-45 (Oct 20, 2011)

jeffkruse said:


> I am looking at the Zebra light SC600W. The size is a little big but OK (the size of the PD31 is perfect).
> 
> 750 lumens for 5 minutes and 500 lumens for 2 hours. If this light can run at 500 lumens for a few thousand hours I will be very happy. If it dies in 100 hours I will be upset.
> 
> ...



I'm going to be the .001% that says "call the manufacturer and ask if the light is designed to run at full output from the time it is turned on until the battery is dead, used in that fashion weekly, what kind of lifespan can be expected from the light with such usage".

IMHO...tiny lights with rather high lumen outputs...run at max output non-stop until the battery is dead...on a regular basis...will kill a light in short order. Kinda like running a Honda Civic at top speed until the tank is dry...weekly...the car cannot be expected to last as long as one used in a more "normal" fashion. Seems like your trying to expect NASCAR endurance out of standard production automobiles. (But I'm not an EE designing LED lights...so what the heck do I know...which is why I would go straight to the manufacture and pin them down for an answer.)


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## Got Lumens? (Oct 20, 2011)

leon2245 said:


> Can you tell us the specific output level you're seeking? Because you'll have to go with a light whose max output is a bit above your target target level (& big enough to continuously dissipate heat) so that its next level down can be used nonstop for the duration of its runtime.



+1 This reasoning applies to other tools as well. My ex. that comes to mind is Welders. A 200A welder may have a 20% duty cycle at full power(too much transformer heat), and can be used continuosly at 125A 100%duty cycle.



dosei-45 said:


> I'm going to be the .001% that says "call the manufacturer and ask if the light is designed to run at full output from the time it is turned on until the battery is dead, used in that fashion weekly, what kind of lifespan can be expected from the light with such usage".



I'm in @ 0.1% group. Call them. I am sure they would rather explain what expectations to expect from the light, than to be replacing multiple lights under warranty.
GL


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## Sparky's Magic (Oct 20, 2011)

@ jeffkruse,

It might be helpful, at this stage, to have a look at the HDS site where Henry has answered some of your queries in his FAQ's page.
Go to Site Map > FAQ > Line 6 - What is the practical difference...? Line 7 - What is Burst? Line 8 - How far can I see...?

Henry is a fellow CPFer and a manufacturer of high quality Flashlights who is, like yourself, a keen caver: In fact, his product arose out of his interest in caving. His knowledge is extensive and his commentaries well worth reading.

Good Luck! :thumbsup:


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## JohnnyStones (Oct 21, 2011)

Every equipment or component gets worn out along with the use or even without use as time goes. Its the fact of nature. If its not than all components we manufacture will be age long, infinite.


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## DaveAnderson (Oct 25, 2011)

Two thoughts for you:

1.) Make sure that you use batteries that are rated for the light. Many vendors will release lights rated for primaries, but not for the higher powered rechargables. I'm thinking about my Nitecore EX10 - it was released for use with the standard primary cells (123's) but would not support the rechargable 16340's I had.
2.) Maybe you could try your own modding of lights. I just saw on the CPF Marketplace forum that a guy is selling MCE LED's for quite cheap (maybe $7 each). If you had a light that you could easily swap the LED's yourself, then just max them out on your expiditions and then solder a new one on when it dims.

Interesting thread - none the less.


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## jeffkruse (Nov 3, 2011)

Just my luck. I just received a new Spark SD6 460NW on Friday. 
I tried the light on Super mode and it only ran for 5 to 7 minutes before reducing the output down to only what I assume was the next lower mode 200 lm. 
I tried to switch it back to the turbo mode but it did not change. The light was warm but not hot.
The light is not supposed to do that. It was 78 degrees in the house and I tried the brand new Solarforce battery it came with and also tried it with my Redilast 2900 at 4.15V’s.

I didn’t even get to try this light out in a cave  I am sending it back.


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## Got Lumens? (Nov 3, 2011)

jeffkruse said:


> Just my luck. I just received a new Spark SD6 460NW on Friday.
> I tried the light on Super mode and it only ran for 5 to 7 minutes before reducing the output down to only what I assume was the next lower mode 200 lm.
> I tried to switch it back to the turbo mode but it did not change. The light was warm but not hot.
> The light is not supposed to do that. It was 78 degrees in the house and I tried the brand new Solarforce battery it came with and also tried it with my Redilast 2900 at 4.15V’s.
> ...



Jeff, 
My SL-5 and SL-6 do the same thing, and this is a normal design function and not a defect.
As you said the Super mode feature will not work for your intended use.
GL


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## jeffkruse (Nov 3, 2011)

The *SD* is not suposed to do that.


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## nbp (Nov 3, 2011)

See? I told you you have a strange electromagnetic field that kills lights.


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## Got Lumens? (Nov 3, 2011)

jeffkruse said:


> The *SD* is not suposed to do that.


Did you verify that with Xyber? I do not see anything that says that it is supposed to run continuos on Super mode. Any comments from SBF/Spark about your findings?
GL


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## psychbeat (Nov 3, 2011)

Xyber and Jake have both said no stepdown on SD series.


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## alpg88 (Nov 3, 2011)

nbp said:


> See? I told you you have a strange electromagnetic field that kills lights.


idk about fields but something strange deffinatly is going on.


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## yifu (Nov 3, 2011)

I thought the SD was not supposed to step down... If you do have an electromagnetic field around you, maybe time to get a single mode, resistor driven flashlight with a faraday's cage around it? Hmm, Electrolumen's EDC lights come to mind, no driver, no multi modes, just a 0.01 ohm resistor in direct drive one mode only. Nothing to blow up. Oh, and use unprotected li-ons, might distort the PCB circuit.


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## DaveAnderson (Jan 23, 2012)

Any update to the mystery?


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## jeffkruse (May 10, 2012)

I havent had any lights die on me in the last 5 months. I use a Zebralight SC600W in my hand and a Spark SD6 on my head along with an Apex. My wife uses a Fenix TK12. I love the Zebralight.


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