After a 300km mountain-hop from Munich to Austria and back, I can report the Active Hybrid 7 is a deft application of a compelling ICE enhancement. I can also confirm this hybrid achieves 250km/h on the autobahns, can climb the Austrian Alps quicker than Maria and is able to glide silently through alpine towns at up to 50km/h.
This, in essence, is the beauty of BMW’s current hybrid-drive system. Employing an electric motor and lithium-ion battery pack to meet two distinct needs: electric-only low-speed motoring, and F1 KERS-like boosting when performance is demanded.
The Active Hybrid 7 shares its entire petrol/electric drivetrain – including the hybrid-spec eight-speed automatic – with the Active Hybrid 5 and Active Hybrid 3. In the 7 Series, the 3.0-litre, six-cylinder turbocharged petrol engine has been tuned for 235kW and 450Nm. When combined with the 40kW/210Nm electric motor, it gives the driver 260kW and 500Nm to play with.
BMW claims a 5.7-second 0-100km/h for the AH7, commendably fast for a two-tonne limousine and equal to the 145kg lighter (and 14 percent thirstier) 740i. In-gear acceleration is equally muscular, even four-up and with luggage on board, not to mention the 145kg of battery, motor and ancillaries the hybrid drivetrain requires over the standard 740i.
The battery pack is situated behind the back seat as it is in the AH5, and it robs the boot of a not insignificant 140 litres (now 360 litres) and useful depth. The underfloor solution of the AH3 is far more practical.
What’s not particularly practical is the 1.35kW/h battery pack’s life. In the bigger, heavier 7 it can sustain a 50km/h cruise for just four minutes before draining. Full-throttle motoring will empty its reserves in just 30 seconds.
But these are minor quibbles. The Active Hybrid 7 is convincing whether evaluated as a boosted ICE sedan or as a fuel-saving hybrid. Of more concern to prospective buyers will be the lost boot capacity. Louis Vuitton luggage doesn't carry itself, you know.