Using LTO Batteries (Yinlong 66160)
Using Solar charge and power output controller https://www.youtube.com/watch?v=uvybwIaeJjE
Using Solar pannel, 400x330 mm poly 20W nominal ? https://www.aliexpress.com/item/1005006820730730.htm
Using RAK Block meshtastic starting kit
Using a waterproof box TBD
Using an antenna TBD
Using a glue to stick to the rock TBD
Need of GPS ?