Wow...I mean, I love the battery life in my 16" M1 Max Pro. Similar specs to yours...64GB of ram and 8TB ssd...but I've never seen two days of use. Not even really a full day...I can get around 6-8 hours on the couch without plugging in.
Huge, and I mean HUGE improvement over my previous 16" Intel, which seemed to make it around 3 hours before calling it a day...
It really depends on your load. I run Safari, a terminal, VS Code, and I turn off Docker and Slack unless I actively need them. Runaway node processes are the biggest battery offender, so those I kill off if I notice them in Activity Monitor. I find 2/5 brightness to be the most comfortable in my space -- I'm surprised to hear others run max brightness which is eye-scorching! It all depends on ambient light I guess.
Also, 6-8 hours is a full work day of laptop time for me. If you have more hours in the day you probably will get less days out of the laptop than me.
That’s crazy, I tend to make it 6-8ish hours with my current 16” Intel MBP, depending on how hard I’m driving it. I usually have about 200 tabs open (don’t ask) in Safari, a few terminal windows(some ssh’ed in to the server), vpn running, maybe an IDE, and a couple other odds and ends.
I have a similar machine (1tb SSD instead) and I'm also getting about 6hrs although I run my machine on max brightness. If I turn it down to half brightness I might be able to break 8hrs but I have no idea how people are getting ridiculous 10-12hrs on battery.
Huge, and I mean HUGE improvement over my previous 16" Intel, which seemed to make it around 3 hours before calling it a day...