Has anyone run their lights for extended periods?

Has anyone run their lights, LED or incandescent, for extended periods? What were the results?

I ask since my typical light usage, other than a headlamp while camping, is sporadic. On an earlier camping trip, I had a Fenix P1D CE as my pocket light, and it got quite hot after about 10 minutes on high.

And since I received my new Fenix L0D Q4, I wanted to test the run time, since it is to be my EDC light. I have used it sporadically since receiving it. Maybe about 30 minutes of burn time in various lighting modes, but mostly on low. I thought I'd see if it would give the 60 minutes of run time on high as advertised, or how close to it I would get. After five minutes, the light was pretty warm. At ten minutes it was hot. At twelve minutes, I turned it off as I didn't want to damage the light. It was cool again in a minute after being turned off. I had a lithium battery in there, if it makes a difference.

I also take a Surefire G2 camping and after about ten minutes, the head is a little warm.

While I don't normally run the lights continuously, I am wondering if it is safe to keep it running when it gets very hot to the touch. Has anyone run their lights until the batteries fail?

Mahalo!

Yes, and unless the manual states specifically not too, it's fine to run them until their dead.

Mahalo iced_theater!

The manual doesn't mention not running it, so it looks like I will try again until the battery fails.

my thinking is if its too hot to hold, its no good

I'd probably keep a fan on the light if your just doing a runtime test in ambient air or maybe a bag of ice on it. You didn't mention if it's a rechargeable battery your using but if so, make sure it's a protected battery otherwise you might ruin the battery.

Thanks for the feedback.

Well, it's been running on high for 50 minutes now and I don't notice any appreciable decline in brightness yet.

It also doesn't seem to get hotter than it is at about the 10-15 minute mark. It is hot, but not too hot to handle.

So far on one lithium AAA, it has gone off an on for about 30 minutes at various brightness levels, about 12 minutes on high, and now an additional 57 minutes and counting.

I grab it to do an unscientific heat check every 10-15 minutes. So far so good. Pretty decent at 75 lumens on 1 AAA.

The little L0D Q4 outperforms the mini-maglite with the 100 lumen terralux drop-in, in terms of brightness and throw. The mini-mag should win on run time though.

As an off-topic aside (not really what you meant with your question) you might be interested to know that powernoodle has been running his HDS for ~16 months non-stop.

depends on what You mean with "extended periods"?

I have used nearly all my small, powerful handhelds for biking because I dont do NRs often enough to buy a real bike light.
These application usually lasts a few hours and its full power all the time

over the years, the lights, strong and rugged enough to be used for that, were:
6R,
8X,
9N (several years)
6P modded with XR-e P4 and Flupic and 18650, since somewhen last year
(and the Cree surpasses the other lights by far)

all are still working and see some use when I lend them around, but I dont like incan in this power class any more.

PS: checking batts with the Cree 6P (running it on full power), means that the light gets quite hot to the touch, when left alone sitting on the desk before. If used (hold in hand, mounted on bars), the heat is moved away quickly. No problem when "in use".
Just dont turn Your Fenix on highest output, put clothing around and then store it in a desk - then You might get into serious trouble...

When a light gets warm very quick, thats an indication that the thermal path is good - but the heat has to move away anywhere. Moving air or the blood of Your hand are very good here, so use this
(remember, as long as something is still grippable, is has a temp of around 50-60 deg C. Below what might be a challenge to the emitter)

hanzo said:

Thanks for the feedback.

Well, it's been running on high for 50 minutes now and I don't notice any appreciable decline in brightness yet.

It also doesn't seem to get hotter than it is at about the 10-15 minute mark. It is hot, but not too hot to handle.

So far on one lithium AAA, it has gone off an on for about 30 minutes at various brightness levels, about 12 minutes on high, and now an additional 57 minutes and counting.

I grab it to do an unscientific heat check every 10-15 minutes. So far so good. Pretty decent at 75 lumens on 1 AAA.

The little L0D Q4 outperforms the mini-maglite with the 100 lumen terralux drop-in, in terms of brightness and throw. The mini-mag should win on run time though.

Click to expand...

By Lithium AAA do you mean an Energizer 1.5v or a 10440 3.7v? Big difference.

I didn't think the L0D would get that hot with a 1.5V battery. I haven't "burned" mine any yet, I hate wasting batteries. But I might try it with my new Eneloops for kicks.

I've run my River Rock K2 Headlight available at Target for something like 7 hours straight on various levels and about 2 hours straight on high, using Energizer e2 Lithium L91.

I have done the same for my Nite Ized converted 1 watt LED Mini-Maglite 2AA.

I run my light (mag included) until the new/ fully charged batts run out. Its gets hot sometimes but if it go poof, I'll claim the warranty. Its a hassle, I know. I want to use my light and not keep thinking about if its gonna go poof.

I test all my lights for an extended period of time when I get them. It avoids the possibility of an early failure when you really need to use it and gives you an idea of the runtime.

So push them hard when you don't need to use them to make sure they work when you do need to use them.

Howdy.

When I bought a SF L1 cree, it had the famous flicker problem, after about 10 minutes. When I returned it, the replacement had the same problem, after around 20 minutes.

Since then, I always run a new light on maximum for 20 minutes or so. If there's any trouble in that amount of time, I don't want the light because I wouldn't consider it reliable.

Just one man's opinion (although, I'm right).

Cheers.

I loaned out my work carry light the other day.. it is a Coast 5 white / 1 red LED model... I went to lunch, and when I got back, the guy I loaned it to was at lunch... I went looking for my light... The machine he was working on was still down, we were waiting on parts... I found my light still inside the machine and turned ON!!! This was an hour+ later... The head was not even warm... but the bumb a$$ first off, leaving my light at the machine... we work in a busy place with a lot of people... Leaving my light turned on as if the say "hello, come and steal me".... Aye aye aye... the whole thing ticked me off... I will not loan him a light again.

I used my surefire G2L for roughly 7 hours straight on night. It was not shut off once during that period. It had roughly 45 minutes on the cells before that. It had dimmed to about 40% or so output by then. The head got hot when the cells were fresh so I done the best I could to hold it by the head to soak up some of the heat to not loose output from the protection setup surefire uses. All in all it made my decision to put the G2L head on my C2 which is my EDC permanately. While color rendition for me is not the best with LED, the runtime in emergency cases more than makes up for it. Prior to this I had ordered a C3, E2E, and E2D for the wife with the intentions of using the C3 and E2E as my edc's. I did order the MN02 lamp for the E2E for 2.5 hours of runtime but I am still debating on whether I will carry them or not after my experience with the G2L. The 7 hour run I done on the G2L is the longest single run I have ever done on any light while the light was in actual use. On a runtime test I ran a mag led drop in with a 2D on alkalines to try to find out how long it would take until total output was lost. I gave up on it with fresh cells and tried a set that would no longer light up an incan and quit the test after about a week if I recall correctly. One cell registered only 50mv while the other cell was around 800mv. That light is carried in the emergency kit in our truck. The light is carried empty with 6 energizer alkalines in a bag. The performance I saw from it made my decision on what light to carry for long term emergency use.

Used my Nautilus on high as a candle to light a room for about 4 hours during a power outage. Light go warm but never hot...

hanzo said:

And since I received my new Fenix L0D Q4, I wanted to test the run time, since it is to be my EDC light. I have used it sporadically since receiving it. Maybe about 30 minutes of burn time in various lighting modes, but mostly on low. I thought I'd see if it would give the 60 minutes of run time on high as advertised, or how close to it I would get. After five minutes, the light was pretty warm. At ten minutes it was hot. At twelve minutes, I turned it off as I didn't want to damage the light.

Click to expand...

I already know that from the computer front (where they usually touch headsinks, get a burn and thing: "it its that hot, it cannot be good and has to fail". But its fine): People vastly overestimate temperatures, and understate the resilence of semiconductors.

If your light is "too hot to touch", this might not be higher than 50C. Even with a bad 10K/W thermal path from the LED, this would be at most 90C in the L0D, which is perfectly fine for any lenghts.

This is not some kind of runnaway process, as the hotter the light gets, the more efficient it exchanges heat with your enviroment.

I run all my lights at least once or twice until the batteries go flat. Then I have one or two lights I burn every night and use them as a night light(s), and also as a way of discharging rechargeable batteries and so that I can put a fresh charge on them. I do that to get a feel of how much run time I can really expect. I generally will rotate the light or the batteries set every night. Its my little quirky way of testing flashlights and lanterns with primaries and different brands of rechargeable. For example if I buy a new batch of NiMh like eneloops, I might discharge them out of the package just to get a feel of how much charge they have out of the box. Then I might charge them up, let them sit for a month, then pop them in a Fenix L2D on high until it shuts off and then note down the runtime. Then I might do the same thing with a set of Duracell NiMh, then I'll repeat the process with the next brightness level on the fenix. I just want to get a feel of the kind of run time I can expect in an emergency.

Generally (and its a quirky habit I have) I have a flashlight on all the time in a walk-in closet in my master bedroom running all the time and it acts as a nightlight at night so I don't stumble if I get out of bed at night. The light spills out into the adjoining bathroom and is just strong enough that I don't have to use the room light if I need to get up and around at night. It also serves to exercise my rechargeables so I can rotate the stock and have cells that are charged up recently. I figure if a set of NiMh have 500 cycles and I rotate my batteries so that each set gets charged once a week, it will take 10 years before those batteries lose their capacity...so what the heck!

I found my L0D Q4 on in my pocket today, first day on my keychain.. I didn't have it unscrewed very far, so I've backed it off a little more now.

Not sure what level it was on, as when it's barely on it flips modes pretty easy, but it was just warm.

Am I misinformed? I was/am under the impression that LED's were supposed to generate LESS heat than an incan.??? Am I right? What are the signs of a LED getting too hot? (in my case, I have a SF G3 with a BOG Q5) I plan to do a test as soon as I get some rechargeables.