2023 Mercedes-Benz C 350e review

Modern EVs generate less range anxiety than they used to but they still need recharging on a road trip. PHEVs help get around this, but are they the right solution?

As things move inexorably towards an electric automotive future, not everyone is ready to make the EV jump just yet. For some a hybrid makes more sense; merely hook up at home and run on electric power alone the next day. That’s presuming most of your travel is in an urban setting and that recharging is practical/convenient.

However, PHEVs are complex, and roughly as expensive as their BEV counterparts so why bother given they’re not emissions free, despite low claimed fuel use figures.

Figures plucked from a hat?

And on that PHEVs seldom seem to achieve their factory claims in everyday running if you neglect to charge them regularly. In a recent trial, a European environmental group tested a trio of PHEVs, each of which was fully charged at the outset and, during a typical commuter route of 55km, the three emitted 20-300 per cent more CO2 than their official ratings.

Two failed to reach their claimed electric city range, achieving 53 to 74 per cent of predicted. The same group in 2020 found plug-in hybrid pollution was sometimes worse than a comparable ICE powered car when using the battery-charge mode (the engine powers the car while also recharging the battery).

European regulators are reconsidering the role PHEVs play in lowering atmospheric CO2 levels, which may force an accelerated shift to all-electric vehicles.

Is regen worthwhile?

On a related subject, there are different ideas on the use of regeneration. The featured car, the Mercedes-Benz C 350e, has three levels, coasting, mild and modest regen, selected by paddles. Porsche and BMW are now having second thoughts about such systems, suggesting overall efficiency is improved with just a coasting mode.

They believe any regen function should be built into the brake pedal. Many new EVs have regen systems with an auto setting which is presumably the most efficient.

Brakes up to snuff?

While on retardation, that’s perhaps the least admirable aspect of the C 350e drive. We often find that vehicles with brake regen have an odd feel at the pedal and that’s the case here. Bear down and nothing much happens initially and then it’s suddenly all on, the effect worse when regen is in its top setting.

On coast mode, the brakes are fine for washing off speed but when pressed, as it were, they feel somewhat underdone. Our best emergency stop of 38m reflects that, not aided by a two tonne kerb weight.

So what about overall efficiency then?

The C 350e’s electric range is impressive. Manufacturers are giving their PHEVs increased electric mileage by installing larger batteries. In the C 350e, its 25.4kWh battery gives it a zero emissions range in excess of 100km. The previous iteration managed half that. I saw 104km of claimed range following an overnight charge.

Mercedes rates overall combined fuel efficiency at 1.6L/100km, though I couldn’t get within a bull’s roar of that. We ran this vehicle as we would for any test car, in a mix of town and country running. About two-thirds out, one-third in, because lots of city running for us involves motorways.

My average fuel use was around 5L/100km, although at times (in town, in EL mode) it was much lower. And the long term data suggested an overall figure of 3.7L/100km, pretty much confirming the European experience (twice the manufacturer’s claim).

Quick enough though?

This shares an engine with the conventional C 300, detuned to 150kW and 320Nm, so along with the 95kW/440Nm motor, system total output is 230kW and 550Nm. Despite the added weight, it is roughly as quick on the acceleration front as the C 300 (just under 6sec to the legal limit) while an overtake was dusted in 3.5sec (100m of clear road required).

It’s really obvious when both power systems are chiming in; on the engine alone the C 350e gets along fine, but with the motor adding input it feels decidedly quick. Given the fuel use rate is around one-half to two-thirds of that registered for the C 300, you can see how the bigger electric motor really does save on fuel use, even in out of town work.

The downside? The engine sounds coarse at times, perhaps because the motor is so dang quiet. There’s a hint of road noise from the Turanzas over the worst of our coarse chip surfaces too but we failed to record a dB reading in the seventies. It looks sleek this car, reflected in a Cd of 0.27, adding to the hush.

Handling and ride pass muster?

This particular tester didn’t have rear-wheel steer which is an option, nor adaptive damping but the ride overall is pretty good, the odd surface with high frequency bumps ruffling its feathers. Bigger hits are handled with grace. There’s some roll and a hint of understeer at the grip limits but these are so much higher than comparably priced SUVs.

However, it’s not as crisp on road as the C 300 which is a delight. And there’s nothing like as much room in the rear seats as you’d get with an SUV, meant more for two than three adults, and nor are the pews that easy to access. Headroom is limited for taller adults too.

The small and pointlessly powered bootlid makes accessing the hold somewhat harder than in an SUV. Split folding is simple though with handles in the boot and spring loaded seatbacks.
Where the previous battery pack used to impinge on boot capacity it no longer does, though at 315L it’s probably about two-thirds the size of a comparable SUV’s hold.

Operationally speaking this is easy enough to drive, though does take a bit of acclimating. Where most other Mercs have the widescreen set-up with dual digital devices under one hood, this is more old school but it still looks fine, with a digital cluster and big central screen.

The drive mode changer is a bit of a pain to access, a stretch toward the passenger side. We very much liked the head-up display, crisp as you like, and situated a little left of your direct line of sight so it impinges even less.

To PHEV or not?

Bit of a toughie this one. Some people just won’t want to go directly to an EV, citing charge inconvenience as an issue for longer road trips. On the flip side, it would seem PHEVs aren’t quite the half-way house they’re made out to be because owners often don’t optimise their electric potential. Road trips in PHEVs will be mainly on petrol alone, making it essentially an ICE powered car.

These days EV makers claim battery range in excess of 500km (likely 350km on a road trip). But increasingly modern lithium-ion battery packs fast charge from 10-80 per cent in a bit over half an hour. The relevant question is: how often will you need to be doing that during your ownership?

Mainly owners will charge in their garage with a home box. And they will feel good about minimising their CO2 ouput, because, as National’s Maureen Pugh now understands, climate change is upon us.

Yes, the C 350e is well specified, with leather trim, self parking, all the driver assistance and safety tech you could hope for, MBUX help when you’re stuck, sat nav, smartphone integration, and adaptive LED headlights. The price ($111,200) is drive-away and there’s five years of factory warranty.

But we’d probably still opt for an all-electric offering given bans on ICE power seem to be getting closer and you may as well go all in if you’re heading down an electric pathway. Certainly that’s what Mercedes seems to be advocating, having flicked the switch recently to a fully electric future.

The EQE will be here soon, along with two other new SUVs. It has a compact EV saloon coming in 2024 as well. That, among other things, would make the PHEV option harder to justify.