That tutorial is nice, I've also been interested in making a solar panel/battery setup to power remote cell boards.
By the way, if it helps any with your board research, here's Waveshare's info on the big 7600 board, setup, demos, manuals, etc...:
https://www.waveshare.com/wiki/SIM7600E-H_4G_HATAnd the little Waveshare board:
https://www.waveshare.com/wiki/SIM7000E_NB-IoT_HATAnd here's the BK-7000 related stuff I got with my Ali Express order (yes the user manual is small but it was enough to get the board up and running):
https://drive.google.com/drive/folders/ ... sp=sharingAlso here's the Simcom.ee documentation site for all their chips, comes in very handy for AT command manuals, design manuals, etc.... I always get the "your connection is not private" warning here, but I haven't found a more complete site yet:
https://simcom.ee/documents/Ok, hope it helps!