A product I recently found on Indiegogo is called FROST SUMMITS. It’s a portable solar charger and power bank to keep you connected in extreme outdoor environments. There are three products: SUMMITS 7 solar charger that can charge a GoPro in 90 minutes; FROST 5000 power bank that can charge even at -58°F; and the BOX CONNECT app to pair each device with your smartphone. The campaign on Indiegogo has been fully funded, with estimated shipping dates of November 2020. There are different campaign levels for the products but the cheapest one is US$45 for the FROST 5000.
Check It Out: FROST SUMMITS Gives You a Self-Heating Battery And Solar Charging