Dubious runtime on new Fenix HM65?

K

Kitchen Panda

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Aug 28, 2011
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I'm looking for a new headlamp to replace my aged Fenix HP11. I was all excited to read the numbers on the new model HM65 - 400 lumens for 22 hours! Wow!

Too good to be true. I suspect it's a 400 lumen needle at 30 seconds and then drops down to 10% fairly rapidly. ANSI ratings allow this, but it makes it hard to compare to more "rectangular" runtime profiles.

I realized a 3500 mAH 4.2 volt LiIon has only 14.7 watthours in it. Let's say you can get 100 lumens per watt, so that's in striking distance of 1470 lumen-hours. 1470 divided by 400 lumens is 3 1/2 hours, about what other single 18650 powered headlamps claim.

Looks like this model is so new there have been no runtime tests published yet. I"m very disappointed in Fenix for publishing what is clearly a nonsense number, without any runtime graphs to warn us what the real output vs. time characteristic is.

Looking forward to the first reviews. I think I will postpone my purchase decision till I can read independednt 3rd party runtime graphs - clearly the headlamp makers have taken the "Sears compressor horsepower" approach to rating their products.

Sadly,

Bill
 
parametrek

parametrek

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Apr 3, 2013
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578
It is even worse than that. If you do the same calculations for the 130 lumen mode it must also have a dramatic stepdown. 50 lumens? Also needs to have a dramatic stepdown. That leaves the 8 lumen low mode which according to the math is probably flat. The HM65R has 7 modes and 6 of the modes must have substantial "turbo" stepdowns. Absurd! A complete 180 from Fenix's long standing reputation for lights that put engineering above marketing.
 
K

Kitchen Panda

Enlightened
Joined
Aug 28, 2011
Messages
216
Location
Winnipeg
It is even worse than that. If you do the same calculations for the 130 lumen mode it must also have a dramatic stepdown. 50 lumens? Also needs to have a dramatic stepdown. That leaves the 8 lumen low mode which according to the math is probably flat. The HM65R has 7 modes and 6 of the modes must have substantial "turbo" stepdowns. Absurd! A complete 180 from Fenix's long standing reputation for lights that put engineering above marketing.

It was down to the HM65 and the Olight H2R and I just took delivery of my H2R this afternoon. About 90% of the choice was due to the bad feeling about the misleading lumen rating.

Bill
 
Lou Minescence

Lou Minescence

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Mar 12, 2011
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1,157
Location
New England US
I’m wondering about runtimes of this headlamp too. 400 lumens for 22 hours would be about 4 times better than a Zebralight ! - too good to be true ?
Looking at the specs on the box it says ANSI / PLATO Fl1 - I found 3 infomercial type reviews on YouTube about the light. No real world testing of output or runtimes.
 
LowLumens

LowLumens

Newly Enlightened
Joined
Aug 31, 2019
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I’ll be watching to see the runtimes on the Fenix. I never had issues with my zebralights yet. But I mainly use lower levels and moonlight more than any level. For me 1-20 lumens when Camping is all I need.
 

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