After 31 days, my current charge level is 79%, which is quite reasonable.
I wanted to share some insights from my month of using the Eufy Solocam S340. Initially, it charged easily to 100% in late summer, but now it stabilizes around 90%, which is fine as long as it stays above 50%. I kept the clear plastic on the solar panel to slow down potential wear over time. Mounted about one and a half stories high at the back of my home, following user recommendations, it hasn't missed any motions so far. My only gripe is the slow opening of recordings and its incompatibility with Homebase 2. Despite that, as my fourth Eufy camera, I'm satisfied overall. I integrated my non-HomeKit cameras with HomeKit via Homebridge for convenient viewing on my Apple TV, and I'm considering adding one more for the side of my home.