Mercedes-Benz has extended its range of plug-in hybrid vehicles thanks to its third-generation EQ technology now being available on both the A- and B-Class. For Mercedes, EQ PHEV cars are a half-way house on its road towards zero-emissions driving which, until now, has only been available on larger models. By 2020, Mercedes is aiming to have no fewer than 20 EQ models ranging from hybrids through to pure electric cars.

In the case of the A-Class, Mercedes is offering it as both the A 250 e and A 250 e Saloon form. The B-Class will be available as the B 250 e only. In all forms the cars share a common drivetrain which has been developed not only for a decent electric-only range and overall efficiency, but also to have the minimum impact on vehicle dimensions and dynamics.

Powertrain in detail

Mercedes has created a powertrain that is perfectly suited to its two compact models and is effectively a scaled-down version of that seen in the C 350 e. It combines a 1.33-litre, four-cylinder petrol engine, lifted from the A 200, with a 100bhp electric motor. Total system output is 215bhp and 332lb-ft which is transferred into drive through an eight-speed dual clutch automatic gearbox.

A 15.6kWh lithium-ion battery holds the juice for the electric motor, and it can be charged with either alternating or direct current via a charger on the right hand side of both the A 250 e and B 250 e. Using a 7.4kW wall box will see 10 per cent to 100 per cent charge achieved in 1 hour 45 minutes from AC, and from 10 per cent to 80 per cent charge in just 25 minutes using DC. Battery weight comes in at a respectable 160kg, with it being located under the rear seats thereby only slightly reducing overall boot space.

Performance and efficiency

Neither the A- or B-class lacks performance in EQ guise. In terms of the 0-62mph dash, the A 250 e cracks it in 6.6 seconds, the A 250 e Saloon is a tenth behind, and the B 250 e adds another tenth to come in at 6.8 seconds. Top outright top speed for the A 250 e and B 250 e is 146mph and the A-Series saloon is 4mph faster.

On electric-only power, all of the variants are capped at 87mph – perfectly suitable in everyday driving. Range on electric power is also ideal for most commutes at up to 42 miles. Once the petrol engine joins the party, combined fuel economy is up to 235.4mpg on the WLTP cycle and CO2 emissions are rated at just 27g/km (on the UK-spec B Class).

PHEV smart tech

As with all good PHEVs and EVs these days, Mercedes has endowed the A- and B-Class EQ models with technology that helps maximise efficiency. An intelligent, route-based operating strategy takes into account traffic, speed and other factors on the way to a planned destination to maximise the use of battery power along the way.

Five different levels of energy recuperation can be selected by the driver, whilst Comfort, Eco and Sport driving modes alter the car's dynamic experience and how it utilises power from the battery and petrol. Mercedes will happily set you up with a domestic wall box, or the navigation system can take you to the nearest public charging station on demand. Furthermore, Mercedes me Charge provides access to over 300 charge point operators across Europe.

In mainland Europe, prices are set to start at around £33,700 for the A 250 e, £34,000 for the A 250 e Saloon and £34,375 for the B 250 e. UK prices will be confirmed soon.

June 2020 update: Mercedes has confirmed prices for the B 250e in the UK market as starting at £35,280 for the B 250e AMG Line Edition. The AMG Line Premium costs from £36,780 and the AMG Line Premium Plus from £38,280.

The A 250e can be had from £32,990 for the hatch and £33,585 for the saloon.