When you record a timelapse video over a long period of time, you usually only take a single image, then a delay, then the next image.

Frames per second are usually only considered when you choose to play back these images afterwards.

In the GoPro Hero 7 Black [manual][1], on page 108 it explains how to set the delay time on a time-lapse.

If you want to record over 7 days and nights, to create a 12 second video at 30 frames per second, you would calculate it like this:

> A 12 second video at a playback speed of 30 frames per second = 12 x
> 30 = 360 frames in total.
> 
> So recording over 7 days = 7 days * 24 hours * 60 minutes = 10,080
> minutes in total.
> 
> 10080 / 360 = 28 minutes between each image taken
> 
> 28 * 360 = 10,080 minutes total

You can always choose to take images more frequently (I would).
You can always dispose of them if you don't want to use them, but it gives you the option to either make your time-lapse longer if you decide to later (but requires more storage space).

Other tips:

* Use a tripod.
* Test the lighting conditions and think about exposure levels on the camera.  
* Fixed exposure is better than variable so long as it is correctly set.




  [1]: https://gopro.com/content/dam/help/hero7-black/manuals/HERO7Black_UM_ENG_REVC.pdf