Are you using an esp32 or Nordic device? The esp32 is way too power hungry for a solar install.
Discussion
This one is using the RAK4631 so is Nordic. I’ve noticed they are seem a lot more power efficient than the esp32 devices I have.
Much much more energy efficient. I learned the hard way with the esp32, but the rak stuff seems good. That said, I still have my repeater parts in a box on my shelf.
