Just dropping this excellent graph here with some measured data. Apologies if it's been shared before. Subjectively, with my eyes, I find the lume to be incredible when fully charged at 1000. And only really takes about 30 secs to charge with a bright full spectrum light such as your phone's flashlight. But, as the graph shows, within an hour its lost 90% of its brightness and is now only helpful in very dark situations. That jives with my experience.
Mike