[24gttghh]

4.9oz or .139 kg: https://www.amazon.com/LightSaver-Roll-up-Solar-Charger-Batt...

Works well on sunny days if you adjust it to point directly at the sun, and it charges in 6-8 hours.

[parametrek]

While that is extremely light, it still weighs as much as 3x18650. Breakeven point would be after four days of perfect 100% utilization of solar power.

Is it practical even then? I'd gladly carry a few extra batteries so that I don't have to sit around camp and keep adjusting the panel every hour.

$100 isn't practical for most people either.