Measured intensity drop after 30 minutes ?- Mtbr.com
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  1. #1
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    New question here. Measured intensity drop after 30 minutes ?

    Hi all!

    I have been looking for a cheap reliable option for night riding and found out Fenix and Nitecore flashlights (EC20, P12, P20, etc.) for cheap, but they all say "950 lumens" and when you read the user manual, a little line mentions that it's 950 lumens for 5 minutes before switching to the next lowest mode (like 250 lumens) for 30 minutes. And then a bit lower for the rest of the ride.

    That's borderline false advertising IMO, and 950-250 lumens drop is quite a difference that coud be surprising while out riding in the woods. But I've never had any worty riding light so I don't know if that would still be ridable.

    I was wondering if bike lights from reputable brands do the same thing ? I was a bit annoyed to have done all this searching and finding this out after quite a few hours of reviews reading and comparaison. I've tried searching but the MTBR shootout tests the lumen output for 3 minutes and not 30 or 1 hour.

    Thanks for your info!

  2. #2
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    Normal bicycle lights do not step down unless there is a heat problem in a poorly constructed light or there isn't enough cooling. Flashlights, on the other hand, since stationary do not not receiving cooling air, get very hot and step down to save the emitter from damage. Each manufacturer sets the time of the step. Best practice in flashlights is to ignore the highest, especially if it's labelled Turbo. These are meant for short bursts only. Better to look at all the modes to see if it meets your needs. A good example: I was deciding between the Nitecore EA41 and the E20, both with a 960 lumen high. The E20 was High 960 then Medium 210, while the EA41 was High 960 and Medium 500. Understanding Medium doesn't step, the EA41 would be brighter.

    Best to look at dedicate bike lights. If you want self contained look at the Fenix BC30 which is around 1000 lumens.

  3. #3
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    Thanks CJHS. That's what I was hoping (bike lights stay at their claimed high output). It's just surprising to see that flashlight companies advertise a light at 960 lumens in "high" mode (no mention of "turbo" or "burst" for Nitecore). Not being in this "field" of flashlights, I was not aware of this disminishing of power. I'm glad I have done more research before clicking on "pay now"!

    I liked the idea of a small, light, self-contained light that has field-changeable batteries, that I could strap to a helmet, a head strap, or my handlebar if I wanted. I'll stay with bike-speciic lights until they refine the cooling of flashlights, or get multiple flashlights : )

    edit : For the Nitecore EA41, they mention a "Turbo" (1020) and a "High" mode (560). I wonder if it drops from High to Medium after a short while. The P20 says 400 on medium with CR123 batteries, which is pretty good considering it's 50$ at BH photo.

  4. #4
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    @Guim, I'll second what GJHS said. Certain torch brands include an auto-power-down timer for their highest or turbo mode. That's one of the reason I've never bought one of those. Then again I've rarely ran a torch on high for more than a couple minutes while riding a bike.

    Anyway, like GJ said, torches are basically designed for quick on/off operation. If you need steady light lasting more than a couple minutes you use the lower power modes so the LED doesn't overheat ( although some LED's handle heat better than others ).

  5. #5
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    Quote Originally Posted by guim View Post
    edit : For the Nitecore EA41, they mention a "Turbo" (1020) and a "High" mode (560). I wonder if it drops from High to Medium after a short while. The P20 says 400 on medium with CR123 batteries, which is pretty good considering it's 50$ at BH photo.
    No it shouldn't drop from High to Medium. SelfBuilt, a very respected reviewer of lights, said after 20 minutes it leveled off to about High level. Google his reviews for good info on any light.

    I took my EA41 with me last night and took some pictures. Its a definitely a spot beam with great throw. I'm not happy with my beam, there seems to be a strong yellow ring around the hot spot. Any Flashlight guys: Does this look normal?
    Here's my Beam Shot Site
    Measured intensity drop after 30 minutes ?-ea41-trail.jpg
    Measured intensity drop after 30 minutes ?-ea41-field.jpgMeasured intensity drop after 30 minutes ?-beam-pattern.jpg

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