When you record a timelapse video over a long period of time, you usually only take a single image, then pause for a delayspecific length of time, then take 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, 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, but this requires more storage space). 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), or to use a higher playback frame rate.
In terms of using other playback frame rates - if you record at 24 or 60 fps, you would need these interval times:
12 * 24fps = 288 frames needed
12 * 60fps = 720 frames needed
10080 / 288 = 35 minute interval
10080 / 720 = 14 minute interval
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.