the Petzl e+LITE, being Li coin cell powered, suffers fr/the same poor brightness-burntime problem that afflicts other Li coin cell powered lights.
i've seen curves of the light o.p. over time for the e+LITE and it resembles other Li coin cell powered lights.
the fact is that after just 30min of continuous burntime on HI, it is producing just 25% of its starting light output. after 1hr of continuous burntime it is only slightly brighter than if it had been running on its LO o.p. setting for 1hr. by 2hr burntime it is the same as the LO o.p. level and remains so for the at least the next 14hrs. at the 2hr mark it is only ~17% of its starting light o.p. level. it continues to drop off linearly until it is ~8% of its starting o.p. level at just 4hr of continuous burntime.
the only mitigating factor is that one often does NOT continuously use a Li coin cell powered light for 30min or longer. however, if one ever needed it as a long burning backup, then, IMO, it is definitely NOT the right tool for the job.
this is the main reason i no longer use, even as a backup, a Li coin cell powered light. IMO, a 9V "transistor" battery powered Pak-Lite is far superior to a Li coin cell powered light.