Get a 10-15w solar charger and you can go quite small. Leave the charger out at camp with the solar plugged in, when you get back to camp, You have a fresh supply of Juice.
in a bright sun in north Texas I was able
To fully charge a 20k bank from my solar panel in about 3-4 hours. I was impressed with the efficiency.
Make sure you get a solar charger that can “reconnect” every time the sun ducks behind a cloud though, I think they have terminology for that something like a smart charge or something, that way you really can leave it out and forget about it (unless it’s gonna rain).
Can always hang the charger off the backpack and grab some sun while hiking or glassing too. Lots of ways to skin that cat