Four things decide whether a solar lantern will keep you company for
years.
First, the ratio of charging time to burn time. For our SOMO light
module the rule of thumb is: one hour of summer sun stores about one
hour of light. And because not every week is summer, it also charges
via USB-C.
Second, brightness — measured in lumens. 100 lumens of warm white light
(3000 kelvin, flicker-free) is enough to read by; an evening rarely
needs more. More important than the peak value is dimming: on the low
setting one charge lasts up to 100 hours, 28 on medium, 5 at full
brightness.
Third, weatherproofing. IP65 means dust-tight and protected against
water jets. A lantern built like that may stay out all summer.
Fourth, repairability. Many solar lights are glued shut — when the
battery tires, the whole lamp goes to waste. The SOMO is modular
instead: the light module lifts out, can be replaced on its own, and
moves between jar, carafe and Adventure Mount.