Hi there~
The main concern is that the power consumption of the pi zero and camera. The pi zero idle power consumption is around 80ma. You had better to add the cirucit to detect the battery voltage and power on/off the raspberry pi zero. You also have to calculate the solar panel size and battery capacity base on the sun light duration and board power consumption. Hope it helps.
<LINK_TEXT text=“https://www.jeffgeerling.com/blogs/jeff … zero-power”>https://www.jeffgeerling.com/blogs/jeff-geerling/raspberry-pi-zero-power</LINK_TEXT>