What is it?
Ford's electrification efforts may not kick into high gear until the 2021 launch of the Mustang Mach-e, but it continues to add mild-hybrid power to its model line-up in the meantime.
The Fiesta is the latest to receive battery assistance, joining the Puma and Focus with a 48V architecture that promises to bring modest fuel and emissions savings to the (already rather efficient) 1.0-litre three-pot Ecoboost petrol engine.
It's a familiar set-up, with a belt-driven starter motor feeding in extra torque courtesy of a small lithium ion battery that relies entirely on regenerative braking to charge itself. This combination cuts down on turbo lag, lets the stop/start system activate while coasting below 15mph and makes acceleration that little bit peppier. It has also allowed Ford to add a larger turbocharger and lower the engine's compression ratio, for what it claims are 5% efficiency gains over a non-hybrid engine.
The battery introduces only a minor weight penalty, so performance remains largely unchanged, with 0-62mph in 9.4sec and a top speed of 126mph. There's a slightly nippier 153bhp version that dips under nine seconds, but neither can be had with an automatic transmission.
Mild-hybrid power arrives as part of a wider update for 2020, which sees all Fiestas with Cross Traffic Alert gain active braking, and ST-Line models like our test car get a perpendicular park function for the active park assist. The optional B&O Play sound system also has its subwoofer relocated, so you no longer have to choose between banging tunes and a bit more boot space.
What's it like?
Subtle exterior badges aside, there’s little to differentiate this Fiesta from any other version. The presence of a battery makes no impact on rear leg room or luggage capacity, and only a back-to-back drive with the outgoing model would reveal any impact on ride quality caused by the minor weight gain.
The function-over-fashion interior isn't as minimal as some rivals, with plenty of physical buttons and switches instead of everything being relegated to the infotainment touchscreen - but that's hardly a criticism in our book. A new set of icons on the instrument cluster, which highlight when the motor is recuperating energy under braking, or dishing it out under acceleration, are the only clue to what's going on under the bonnet.
The former is handy, because the Fiesta disguises its regenerative efforts very well indeed. The brakes are a lot less grabby than the ones on Suzuki’s mild-hybrid Swift, gradually stripping off speed and encouraging you to coast from further back as you approach traffic queues - something you’ll need to do frequently if you want to match Ford’s WLTP-tested fuel economy figures. The stop/start system is also very smooth and it's quick to react when it’s time to get moving again.