This is a huge issue and very difficult to solve. I'm a professional polar bear and northern lights photography guide and this has been driving me crazy. I have a brand new R5 ii and even in temperatures slightly above freezing, the camera was showing me a battery dead symbol and indicating to change the battery - even though the battery was still fully charged. When I plugged in a USB-C charging cable to the camera, the 100% battery symbol would confirm the battery charge, but the camera would not operate.
I sent it back to Canon and they replaced the mother board so I hoped the issue was resolved.
Last night, with my aurora guests, using the battery grip with 2 fully charged NP-e6p batteries, I only got approximately 30 shots before the battery error occurred and the camera would not operate. The temperature was approximately -20 C. I put in two warm fully charged batteries and got the same error.
This is just unacceptable. While many photographers have had great success using the R5 ii and R5 classic, Canon needs to make good and replace these bodies until they can actually figure out what the problem is.
I've been using Canon cameras at temperatures as low as -50 C for the past 40 years. It breaks my heart that for the remainder of aurora season I'll have to use my 1-year old 5Ds. It's a nice camera but it sucks a low light.
Please Canon - help us out. I can't recommend Canon to my guests at the moment and I'm a 40+ year canon shooter.
