The prices change every 5 minutes for sales and such, but there's generally always a ton of 50 cents a watt solar panels on Amazon.
Permanent installs that work unattended are slightly scary and have to be done right so something doesn't leak or start a fire, but the portable folding panels are usually similarly cheap.
You could get one of those plus a charge controller and LiFePo4 for not too much.
Everything still needs to be done carefully though, and unfortunately almost all cheap charge controllers have a ton of idle power draw, they're kinda crappy compared to the tech built into a random cheap solar generator, I don't think you can make anything as nice as a commercial generator for cheap.
Most the DIY education kits for kids type stuff seem pretty crappy too.
An ESP32 module with onboard lithium charging plus a USB-C folding panel has a lot of possibilities though, if you have any projects ideas that could be done with such things.
Permanent installs that work unattended are slightly scary and have to be done right so something doesn't leak or start a fire, but the portable folding panels are usually similarly cheap.
You could get one of those plus a charge controller and LiFePo4 for not too much.
Everything still needs to be done carefully though, and unfortunately almost all cheap charge controllers have a ton of idle power draw, they're kinda crappy compared to the tech built into a random cheap solar generator, I don't think you can make anything as nice as a commercial generator for cheap.
Most the DIY education kits for kids type stuff seem pretty crappy too.
An ESP32 module with onboard lithium charging plus a USB-C folding panel has a lot of possibilities though, if you have any projects ideas that could be done with such things.