I wanted to set up my Thinkware F800Pro to a 12V battery to continuously record over night from like 8 or 9pm until the morning 7am. I purchased a 128GB microSD card that should be plenty of room for this. However I find my footage ends around 3:30 AM. I found that in the cont_rec folder...
So it looks like you cannot use all space but that's not true, those .temp files are necessary and overwritten continiously.
If you connect card to PC you can also setup spare for different partitions(Actually Folders) where the recordings are saved.