Has anyone ever tried this? How did it work?

Total failure. You can replace a small portion of the charge during the day, but no way to keep up with the demand overnight. You would need at least 3 battery packs, and rotate them while others charge.
Bill

It should work well enough, but is not something I would rely on- weather can interfere.

The way a friend of mine did it was actually the right way- figured out what the currrnt need was to recharge the battery and brought enough of the deployable solar panels to get the requisite charge in his batteries. He did make some assumptions like at least 8 hours of usable daylight and assumed some efficiency loss… but he is an electrical engineer.

I wouldn’t get the stuff they sell for charging a cell phone to do it.

I have not seen anything with a built in solar cell for this.