“Backpackinglight.com did an independent test on the EOS and found that it lasted 216”

All I could find was http://www.backpackinglight.com/cgi-bin/backpackinglight/princeton_tec_eos_headlamp_review.html It just shows 2 hours on high. So don’t expect 216 hours on high (unless one says moonlight is pretty bright).

“Princeton Tec hates to publish exaggerated battery output times, but I think they need to revamp their website based on their new findings”

Maybe so. Taking it out to 5 lumens though or even 1 lumen is not useful at all (though long run time!) when we need it on high. I hope they stay with the 50% runtimes; that’s more useful.

“It's also a matter of physics that when you have more batteries (3 vs 1) powering a similar LED (Rebel vs. Cree) using voltage regulation, you will get longer burn times.”

It depends how good the single-cell boost converter can squeeze every last drop out of a battery. Let’s use the EOS (105g) and Fenix L0D (14.5g) as an example. At high, the EOS will give 50 lumen until it drops 50%--- in one hour; but let’s give it 3 hours for the benefit of a doubt. Integrating for total light we’ll call that 50x3 = 150 lumen-hours on 3 AAA batteries. Or rewriting for battery efficiency = 50 lumen-hour/battery

Now the LOD gives 75 lumens for 1 hour (until 50%) for 1AAA battery. This gives 75 lumen-hour/battery. Thus we see the L0D is 1.5x more efficient than the EOS II.

Thus for the ‘high’ setting, you need to carry at least 1.5x as many batteries for the EOS II. The same analysis can be had for the ‘med’ and ‘low’ settings.

I’ll stick another neat tidbit in here. If we move to the AA Fenix L1D, that is still half the weight of the EOS II. And the L1D gives 160 lumen-hour/battery. AAA and AA batteries usually cost the same so the L1D is a much more cost effective approach (at least 3x cheaper on high).


“The other thing I would caution against is published lumen outputs. There is no current standard.”

People use to use Lux and candlepower (illuminance). I’m glad they got away from that. Lumens (total light output-- radiance) is the way to go. Surefire started that with their lights and it made sense. Lux meters just don’t take into account beam angle and distance. So my lux reading will be different than someone else’s.

I like specs in Lumens, and a beam angle (or beam shot). Integrating spheres measure lumens and these instruments are not had by many people (expensive). I believe PT and Fenix have ways to measure the total light output of their lights. These meters are accurate.

I remember when Streamlight use to spec in candlepower. Now they switched over to lumens. That’s the way to go.

“I guarantee anyone who compares the new Rebel EOS side by side with any other light at it's price point will come away impressed.”

I sure would love to see it side by side with the Fenix L0D.

-Barry