The reason the battery life times are so low on the REI site has to do with how they measure battery life (burn time) and distance. The full and half life times reported on the REI site for all of the Petzl (as well as Princeton Tec and Black Diamond) lights are dramatically shorter than what we all report on our websites as well as on packaging. I have spoken with REI and they are in the process of changing the burn times to reflect the more common method of measuring both distance and burn time.

We test out lights according to the full moon standard, which is a lighting protocol that states the minimum amount of usable light is equivalent to the amount of light produced by the full moon, on a clear night, in an open field. You can read more about how we measure lights at: http://en.petzl.com/petzl/frontoffice/Lampes/static/referentiel/present_referentiel_en.jsp

Per the lighting protocol, we test our lights at 70 degrees F and tie battery life (burn time) performance to 0.25 lux (full moon standard). The devices we use to measure lux are an Integrated Sphere and CCD Camera. When the amount of light drops to 0.25 lux we consider the light “dead” and not usable – this is the cutoff point. Using this approach the burn time for the e+LITE on economic mode at 70 degrees F is 45 hours, whereas REI reports a burn time of only 5hrs. 8 min. This difference, which is quite large, is due to the different testing methods.

I asked the team here in France why we don’t provide burn time and distances for our lights at 0 degrees F. The answer is we cannot measure the lights performance at that temperature due to the operational requirements/parameters of the CCD and Integrated Sphere. However, we can and have measured the light’s performance at that temperature by measuring the current and voltage of the light and are confident of a burn time of well over 20 hours.

The e+LITE has the following burn time/distance:

(NB: these figures aren't formatting well. Max is when using the maximum setting, and Econ is when using the Economy setting)

e+LITE

Burn time: Max=35 h Econ=45 h

Distance:

t0 Max=19 m Econ=11 m
t0h30 Max=12 m Econ=10 m
t10h Max=5 m Econ=5 m
t30h Max=3 m Econ=3 m