Building a portable powerplant that can be charged with either the sun, AC voltage or 12 volt DC is pretty simple. There are just a few simple considerations and then you have MANY options. Here’s how I hooked up a box for camping to run my ham radio and other electronics.
Make a prepper stove with just scrap
If you’re not into actually making a stove and don’t have the mad skills of Yankee Prepper (but you should really learn how), I’d suggest getting something like the Solo Stove. These things are super-efficient and great to have for not only camping but for around the house during extended power outages.