The 15pm has a 100ma bigger battery than the 14pm - yet has the same battery run time estimate.
This year’s 3nm SOC seems to not be any more efficient than last year’s.
We’ll see once someone can do a battery test, of course, if they are testing a year old 14pm to a brand new 15pm the new one is gonna do better.
Hopefully Apple comes out with a usbc MagSafe battery pack soon.