Like Pete, I also use Krill lights, with lithium batteries : very long shelf life, 50 hours run time (for the Extreme models), on/off possibility ... I got some in my rucksack, in the car and my suitcase : it's enough to light a hotel room, in order to cross it without banging in the furniture, in case of power shortage.
I still keep some Cyalum (or another brand ...???... not sure...) in the car, just in case I need to toss a few of them behind my broken down car, on the side of the road and leave them there .....
Alain
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Alain