RTC without WLAN-Connection

Hello!

I have a Photon, thats conected to my WLAN at home and the RTC-Clock is syncing. The display shows the right time - everything is perfect. A battery is connected to Vin for the RTC.

Now I want to disconect the clock from power, move it to a place without WLAN, repower it and want to see the time from the RTC. But my Photon does nothing, because it waits for a WLAN. Is there a way to check if WLAN is available and connect to it, or work offline when no WLAN is near?

Thanks for your help,
Robert

Similar questions were asked tons of times
https://community.particle.io/search?q=without%20wifi

These doc keywords will also help
https://docs.particle.io/reference/firmware/photon/#system-modes
https://docs.particle.io/reference/firmware/photon/#system-thread