They use a lot less power then the Elecrow A6 module board with the 32u4 Arduino.
Want to see how much. Battery charged from 87% to 97% in sensor reading cycles that are 15min each.
Its a cloudy day today and i did not use that 2.5W solar panel. I used a tiny tiny 0.6W panel that runs at 6V. The 2.5W panel runs at 5V.