Okay, it was the fuckup in phosh 29 which would cause it to wake up for something irrelevant, then get in a loop where the warning 'the phone will suspend now' would wake it up again and again. Last few days, if anything like that would happen overnight, it would have 0% or 2% power in the morning, and keeping it plugged into a PC wouldn't get it above 52% of charging (charger would get it above 90%, though).
Flashed the phosh 36 to eMMC and so far so good - just turning the screen off and keeping the suspend to 2 minutes after that manages to keep it charged. Got it off the cable yesterday morning, and now in the afternoon it still has 36%. This becomes usable now.
Flashed the phosh 36 to eMMC and so far so good - just turning the screen off and keeping the suspend to 2 minutes after that manages to keep it charged. Got it off the cable yesterday morning, and now in the afternoon it still has 36%. This becomes usable now.