Mercedes C-Class 300 e test: the rechargeable hybrid that drives far

While the Mercedes EQS limousine announces the best range of 100% electric cars (up to 784 km on a single charge!), the new Mercedes C-Class also signs its small record among plug-in hybrid family cars: 111 km of maximum electric range in the WLTP mixed cycle, when the BMW 330e and Volkswagen Passat GTE travel only 60 km before restarting their petrol engine. The secret of the C 300 e Class? Its twice the battery capacity, announced at 25.4 kWh, more than a 100% electric model five years old (the Renault Zoe and BMW i3 capped at 22 kWh until 2016).

Its second strong argument concerns its recharging speed. Able to drink water, like some rivals, from public 11 kW terminals (a full charge then takes 2 hours, instead of 14 hours from a domestic socket), the Class C 300 e also collects recharges on a fast terminal while running continuous up to a power of 55 kW. Enough to reinvigorate the battery to 100% in 30 minutes, or time for a sandwich break on a long journey. Naturally, these qualities weigh heavily in the balance, very real first, then price: at 2,080 kg and 59,400 € minimum, the C 300 e weighs 430 kg more and starts 8,850 € higher than a C 200 gasoline engine with 204 hp.

Class C plug-in hybrid price

Like the other engines, the C 300 e offers the choice between three levels of finish. The Avantgarde Line at €59,400 already includes two 12-inch screens, 64-colour ambient lighting, heated front seats, reversing camera and induction charging; the Business Line at €60,300 adds metallic paint, while the AMG Line at €62,350 boosts the shields, rims, seats and steering wheel, but leaves out the steering and sports chassis of the thermal versions, not compatible with the plug-in hybridization. Despite the pretty price, the use of options unfortunately remains essential to benefit from a simple hands-free key, an adaptive cruise control or a cable for public terminal of 8 m instead of 5 m (then a little short because the charging hatch is located on the left side, opposite the sidewalk). Detailed on the following page, the attractive option packs range between €3,750 and… €8,150.

No bonus comes to soften the price of the C 300 e, the €1,000 bonus allocated until June 30, 2022 remaining reserved for plug-in hybrid models billed for less than €50,000. Even by integrating the exemption of all or part of the cost of the gray card (also offered on the other Class C with simple light hybridization), the additional cost of the technology will be almost impossible to make profitable for an individual. Professionals are better off here thanks to a total exemption from tax on company vehicles (TVS), which would reach new heights on a model of equivalent power (313 hp combined here).

Electric autonomy: nearly 100 km!

Housed in the nine-speed gearbox, the electric motor alone develops 129 hp and 440 Nm of peak torque. Sufficient to start quickly at the green light but not to energize the reminders, more any beyond 100 km / h. On our test route for plug-in hybrid models (combining secondary roads at 80 km/h, expressways at 110 km/h and crossings of fluid villages), the C 300 drove 97 km without waking up its heat engine, which is a lot, a lot further than a Peugeot 508 SW Hybrid 225 (37 km) and than the former leader of our ranking, the Toyota RAV4 plug-in hybrid (66 km). The Mercedes would have even exceeded the 100 km mark with milder weather, the thermometer peaking at just 5°C during our test.

This nice radius of action not only makes it possible to avoid daily connections to the mains, but also to significantly reduce fuel consumption over long stages. If the electric range drops to 60 km at 130 km/h, it makes it possible to equal the average fuel consumption of a diesel after several hundred kilometers (see details in the following chapters). Our pre-production model being devoid of a DC charger, we were unable to test refueling on fast terminals. But their interest will depend above all on the tariff applied by the energy suppliers. Without an Ionity subscription, for example (which charges €0.79 per minute of charge), staying connected for 30 minutes will cost €24 but will barely offer 60 km of autonomy on the motorway. Driving on unleaded will be two and a half times cheaper in this specific case, the Class C not being so greedy empty battery. Demonstration.

Class C 300 e test on the highway

On the highway swallowed at 130 real km / h, the C-Class was satisfied with 7.5 l / 100 km with a “flat” battery. This value will drop if the battery has been charged before departure, as shown in our averages chart below. Reasonable values ​​are allowed by the care taken with aerodynamics, which also serves the good soundproofing of air noise at this speed. Hybridization finally contributes to this sobriety, because the battery regenerates slightly on the descents before restoring the energy supporting the 2.0 petrol 204 hp in the ribs.

Too bad you have to use options to have the relevant semi-autonomous driving system, combining adaptive cruise control with active centering in the lane in an extended pack billed at €2,350. The latter was absent from our C-Class test, which was content to beep or vibrate its steering wheel when the car straddled a continuous line.

Fuel consumption on the highway with 100% battery at the start*

Class C 300 e road test

Same exercise here with a Class C whose battery gauge hardly exceeded 0% at the start. On a secondary road interspersed with deserted villages, the paddles at the wheel become invaluable allies: a flick on the left one reinforces the recovery of energy on deceleration, two flicks on the right one let the car coast to keep as much as possible of momentum. Lazy people can let Auto mode do its thing, which adapts the level of regeneration according to the environment and/or speed limits. A well-managed system, comparable to that of the latest 100% electric Volkswagens.

Class C 300 e test in town

A consumption table would not make sense here. The kilometers traveled in the city are low, and the appetite of the Mercedes C-Class is quite volatile there when the battery is not recharged. If it is a question of crossing a village en route, engine and passenger compartment at temperature and battery slightly regenerated by previous braking, the C 300 e knows how to crawl in electric at 50 km/h stabilized and display a consumption of only 5 .5 l/100 km. If the caps drag on or if the traffic lights multiply, the value will approach rather 8 l. The take-offs of this heavy sedan from a standstill call more on the combustion engine, which wakes up from 30 km/h with a light foot, or even immediately if you don’t dose the accelerator.

But it is the short cold journeys that penalize consumption the most, since the 2.0 runs at high speed after a long sleep, especially in winter to regenerate the battery and then supply the heating. The computer can then exceed 10 l/100 km and will quickly disappoint users who do not play the game of recharging (connecting to the mains also allows you to program the heating before departure by avoiding “pulling” on the battery) . At the same time, the C-Class is less pleasant to drive around town with noticeable jolts on the asymmetrical deformations of the roadway, a front bumper that often rubs on speed bumps and braking difficult to dose, as often on electrified models. The inconstant pedal travel and the impossibility of performing degressive braking before stopping degrade the fluidity of walking in town, like the small jolts sometimes felt when upshifting or downshifting in electric mode. To be refined.

On board the C 300 e AMG Line

Find the results of the test, the technical sheet, and all the prices, equipment and options of the Class C 300 e on the following page.