At the moment i'm using zzmoove governor, but still testing others. But 2 days sounds much, but it's still bad. I barely use the phone during the day, with a stock installation and default kernel i get 1 1/2 days. So basically every hotplugging governor that puts the unused cores to sleep when the phone is suspended, will do the trick for me. My old Jolla 1 lasted 5 days with one charge...

I 'm trying to build a new kernel with some backported features from newer CM kernels, but at the moment the Nexus reboots directly when put to sleep or during boot or in the first few seconds after start...hard to debug