Re:BMW delivers its 100,000th electrified vehicle this year
by BoorishBears on Tuesday December 19, 2017 @01:54PM
(#15962899)
You can put it in Mountain or Hold, Mountain waits till the battery hits ~25% and then tries to hold it.
Hold will (try to) hold the battery where it currently is.
Both essentially do what you describe, use ICE primarily and the battery as a secondary. The battery mostly ends up only being used under heavy acceleration at highway speeds (ie, to get your last 10-20 mph of your speed).
I.e. only use the battery to get the last 10-20 kph of your speed.