I do not know if this will be helpful or not, but I think people are curious about this topic, but the question is feasibility. Usually when people think of Solar Powering a Raspberry Pi it is just to see if it will work and how cheaply you can do it. Anyways this is what I am playing around with in my spare time.. (I usually get about half an hour to fool around with it on weekends).
I cannot speak for the person that started this thread, but that video did pique my interest. I have been curious about using Solar to power Raspberry PIs as well. Not so much for mining BUT to just test if it could keep one running. I am not electrically inclined so I have to hunt for what looks to be easy. To start (about 2 weeks ago) I purchased this cheap Solar Panel -
https://www.amazon.com/gp/product/B07F83M356/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 I hung it in my garage window. It has two USB ports. I connected one to a Bluetooth Speaker (micro USB) to charge and one to a little Sega handheld game (mini USB) console. This panel only worked during the daylight of course. The game console had been powered off for at least 2 years, but may have had a tiny charge. The Bluetooth speaker had been powered off for at least 1 year but had a minimal charge. With both plugged in and left, it took right at 2 days for the game console to fully charge and approx 3 days for the speaker to charge. This was a direct charge with no battery.
I then ordered this battery kit from amazon -
https://www.amazon.com/gp/product/B07XFBN7HX/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1 this is a 2 pack Miady 10000mAh Dual USB Portable Charger, Fast Charging Power Bank with USB C Input, Backup Charger for iPhone X, Galaxy S9, Pixel 3 and etc. Both had approx 40 - 50% charge already based on the lights that lit up. The solar panel struggled to charge both based on the blinking light. For 1 day it seemed to trickle charge between the two ports. So I moved one to a separate plugged in charger drawing from the home current. The one plugged in charged fully in 1.5 days. The one plugged into the solar panel was fully charged after 2.5 days. Given the solar charged unit was only able to charge for 50% of the time. I didn't think this was too bad. That was where I left off last weekend. This is where my lack of knowledge of Solar kits me. I do not know if this will work or not, but I am thinking my next test is to is to plug one of these batteries to the solar panel, and then connect a something to the battery and leave that item on to see what happens. If that seems to work, then I am thinking i should connect something cheap that I can interact with such as an ESP32 similar with a camera to see what happens. Maybe point the camera at the battery so I can view it remotely.
If that test pans out then the next step would be to connect a RaspBerry Pi Zero W to the battery and power it on and and see how it works, Then once I have it up and running, just keep an eye on it and check it to see if it loses power, maybe try to surf the web. As for mining, I don't think mining BTC would be a starting point, maybe trying to mine DuinoCoin, then if I can get to a point where I can sustain a Pi mining Duinocoin then look at USB mining BTC at stock speed or something.
I am wondering if it makes more sense to look at something like this instead of the cell phone battery banks.
https://www.amazon.com/dp/B09MTFFQG6/?coliid=IA0V6NODFLVOF&colid=1BQ3BM9DD6FR6&psc=1&ref_=lv_ov_lig_dp_it or this one as the first one seems too cheap,
https://www.amazon.com/dp/B09MTFFQG6/?coliid=IA0V6NODFLVOF&colid=1BQ3BM9DD6FR6&psc=1&ref_=lv_ov_lig_dp_it Please note that all the amazon links I list in this are not trying to get anyone to buy anything. these are just intended to be visual references.
I don't want to hijack this thread, but let me know if you want to know how the above pans out.
