Hi, I just registered to this site. I have a GX80 since this summer, and did a few shoots with it. Battery life was around 35 minutes (4K, Ibis on, manual focus). According to the manual, actual shooting time is 40min in 4K.
The G85 manual states the actual shooting time as 45 min, so you should at the very least also get 35 real minutes out of it.
I got 2 spare (non-Panasonic) batteries. It is important to get them charged right before the video shoot, they will lose capacity when just sitting there for a week.
