Mercedes has entered its smallest passenger model into the plug-in hybrid club.

PLUG-in hybrids are a small - 496 units this year to the end of August - and technically fascinating market segment that sometimes looks poised for expansion.

And at other times it seems destined to remain a specialised niche, somewhere in the no-man’s land between hybrid-assisted models and battery EVs.

So far Mitsubishi has been the only brand to find traction in the PHEV sector.

Outlander PHEV sales account for well over half of all plug-in hybrid sales in New Zealand this year. And that’s a market with 20 different models on sale – and quite a few more on the horizon.

The Mini Countryman PHEV is the number two seller, but at about one-sixth the volume achieved by the Outlander.

Luxury brands also dabble in plug-ins and Mercedes-Benz has so far offered C-Class sedan and GLC SUV plug-ins. The third offering in its so-called EQ Power family is the A 250e hatchback just announced for the New Zealand market.

A further addition to the A-Class family - that now stretches from A 180 to ballistic AMG 45 S 4Matic - the A 250e hits a $72,300 price point. That makes the plug-in version $1900 more than the A 250 4Matic but still considerably more affordable than the hot Mercedes-AMG A 35 4Matic.

With a 15.6kWh battery the A 250e will travel further than most PHEVs on a single charge - an ADR-rated EV range of up to 73km.

A 1.3-litre four-cylinder turbocharged engine develops 118kW output and 250Nm of torque working in tandem with a 75kW/300Nm electric motor which can also recoup additional energy during braking.

The combined output of the hybrid powertrain is rated at 160kW and 450Nm. Acceleration from 0-100km/h is brisk at 6.6 seconds and combined cycle fuel consumption (ADR test) is 1.6L/100km with tailpipe emissions measured at 34 grams/km CO2.

The architecture beneath the fourth-generation A-Class was engineered from the outset to accommodate PHEV components.

The water-cooled lithium-ion, high voltage battery is mounted in the rear of the A-Class hatch and weighs 150kg. Thanks to a smaller 35-litre fuel tank and a repackaged exhaust system - with a rear muffler housed in the transmission tunnel and a centrally positioned exhaust outlet under the floor – there is only a small compromise of load space to 310 litres.

The A 250e delivers power to the front wheels via an 8G-DCT Hybrid eight-speed auto designed to maximise the all-electric range. There are ‘Electric’, ‘Battery Level’, `Comfort’, `ECO’ and `Sport’ drive modes.

In the Electric programme the braking recuperation strength can be selected via paddles behind the steering wheel.

For the first time on a Mercedes-Benz vehicle, the combustion engine is started by the electric motor – the A 250e does not have a separate 12-volt starter. And the A 250e is also the first Mercedes-Benz plug-in passenger model to offer DC charging capability.

The A 250e is equipped with a Type 2 plug capable of delivering charge via AC power at a rate of up to 3.7kW.

To maximise the speed of charging at home or work, customers can install a Mercedes-Benz Wallbox Home charger.

This can be installed on regular single-phase power (by a qualified electrician) to deliver up to 7.4kW, or up to 22kW on three-phase power.

As a $1990 option, customers can purchase a DC Charging Package which enables DC fast-charging at 24kW via a Type 2 CCS plug.

Using DC charging, it may be possible to charge from 10 per cent capacity to 80 per cent in as little as 25 minutes. The Charging Package also doubles the AC charging capability to 7.4kW.

Aside from its powertrain and charging technologies the A 250e offers a familiar package to premium hatch customers.

Standard equipment includes 18-inch Aero alloy wheels, the intuitive MBUX infotainment system with voice control and a fully digital widescreen cockpit, NTG6 navigation, Artico upholstery, smartphone integration including wireless charging and LED headlights.

Pre-entry climate control can cool or heat the vehicle before it’s started thanks to the fitment of an electric refrigerant compressor. This can be controlled via the Mercedes me Connect suite of services from a connected smart phone, which also includes remote vehicle status monitoring.

Standard safety equipment includes Blind Spot Assist, Active Lane Keep Assist, Traffic Sign Assist, nine airbags, Pre-Safe accident anticipation system and Adaptive High Beam Assist head lights.