From £70,4709
Hushed, flexible and remarkable value for money. Arguably more fit-for-purpose than any other ‘S’.

What is it?

The Mercedes-Benz S500 Plug-in Hybrid offers something for nothing – in theory. 

As well as being the latest addition to the S-class range, it looks like a bit of a no-brainer for the chauffeurs and fleet drivers that make up the majority of the car’s customer base.

The list price of the car may be £90k, but with this car saving your typical 40 per cent BIK-rated company car driver just over £300 per month compared with the S300 Bluetec Hybrid, the S500 Plug-in Hybrid works out level on price with the cheapest-to-run diesel on a monthly basis – and quite a lot cheaper if you happen to live in London and regularly pay the congestion charge.

It’s powered by a 328bhp twin-turbo 3.0-litre V6 petrol engine working in tandem with a 114bhp electric motor. The former may come as a disappointment to Merc’s traditional customer if they’re expecting the S500 badge to grace a V8-powered limousine as it always has before.

But they won’t have much to moan about when they learn of the S500’s vitals. The 443bhp combined output is as much power as any non-AMG-branded V8 might provide, while the hybrid system’s 479lb ft of torque – available from just 1600rpm – is considerably greater.

The new S500 has an 8.7kWh lithium ion battery that can be charged via a seven-pin Mennekes-style cable or from a three-pin domestic outlet, the latter taking five hours from flat. It weighs 180kg more than the Bluetec Hybrid, but it’s still 2.6sec faster to accelerate from rest to 62mph, and it has an electric-only range of 18 miles.

What's it like?

The market is filling up with plug-in hybrids that make a lot of sense on paper but whose appeal slowly erodes as you become familiar with their real-world capabilities. The S500 is not one of those cars. It’s as driveable and easy to use as any S-class in the range, but more refined and impressively frugal within its comfort zone.

Once the battery’s flat, in normal mixed-road commuter use, it’ll return around 30-to-the-gallon. Most owners are expected to tackle shorter trips and a greater proportion of city roads than that usage pattern contains, and our test route suggests that doing so could add 50 percent to that real-world return.

The car’s four drive modes allow it to juggle electric and petrol power in ‘hybrid’ mode, to run exclusively on battery power, to maintain the current battery charge level in ‘Save’ mode, or to return the battery to full charge via the combustion engine in ‘Charge’.

The controls are light and undemanding, just as they are in any S-class – designed to be easy to modulate for unerringly smooth progress. The inconsistent pedal response of Mercedes’ lesser hybrids would never do for an S-class, but this one doesn’t suffer with it. There’s pleasing progressiveness to the initial brake pedal travel, and while you can just about hear the petrol engine starting and stopping as you vary your accelerator inputs, the engine response is always predictable.

Having almost 500lb ft available so far below 2000rpm makes a telling contribution to flexibility. You can make supremely laid-back progress in this car without dawdling or holding anyone up, simply because all that torque allows you to slip away from standing so effortlessly.     

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Refinement in the car is genuinely outstanding. If anything, the absence of combustion noise just gives you a greater sense of awe about the cabin’s suppression of road and wind noise, barely a whisper of air or rumble of tyres being allowed to disturb the onboard calm. The car’s ride is pillow-soft and quiet, taking the edge off both gentle and sharp intrusions brilliantly.

The S500’s luxurious bubble can be burst if you hurry it – not that you ever feel remotely inclined to. This car’s dynamic brief is about as single-minded as they come: be comfy. It’s wonderful if you drive it with the dignified restraint you’d need to keep a knight of the realm in the back seat from looking up from his iPad. Body control becomes imprecise, and the steering a bit vague, if you try to hustle it too quickly.

Should I buy one?

On the evidence of a fairly short test drive, and assuming you’re a company car tax payer and a city dweller, definitely yes. 

Expect further coverage and a more detailed verdict before too long. But on face of it, this could be the definitive version of what, for many, is the world’s definitive luxury car.

Apparently uncompromised to drive and to use, it will deliver peerless luxury, fine urban economy and remarkable relative value to a good proportion of heartland S-class buyers who’ve been ill-served by noisy diesels and thirsty petrols for decades.

The S500 Plug-in Hybrid doesn’t render other versions of the car any less important, and there are limousines with a more balanced blend of dynamic talents for owner-drivers. But it’s an outstanding example of electric powertrain technology intelligently applied and thoroughly executed.

Mercedes S500 Plug-in Hybrid AMG Line L

Price £87,965; 0-62mph 5.2sec;
 Top speed 155mph (limited);
 Economy 100.9mpg (combined);
 CO2 65g/km; 
Kerb weight 2215kg;
 Engine V6, 2996cc, twin-turbo, petrol, plus electric motor;
 Power 443bhp at 5250-6000rpm;
 Torque 479lb ft at 1600-4000rpm;
 Gearbox 7-spd automatic

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Matt Saunders

Matt Saunders Autocar
Title: Road test editor

As Autocar’s chief car tester and reviewer, it’s Matt’s job to ensure the quality, objectivity, relevance and rigour of the entirety of Autocar’s reviews output, as well contributing a great many detailed road tests, group tests and drive reviews himself.

Matt has been an Autocar staffer since the autumn of 2003, and has been lucky enough to work alongside some of the magazine’s best-known writers and contributors over that time. He served as staff writer, features editor, assistant editor and digital editor, before joining the road test desk in 2011.

Since then he’s driven, measured, lap-timed, figured, and reported on cars as varied as the Bugatti Veyron, Rolls-Royce PhantomTesla RoadsterAriel Hipercar, Tata Nano, McLaren SennaRenault Twizy and Toyota Mirai. Among his wider personal highlights of the job have been covering Sebastien Loeb’s record-breaking run at Pikes Peak in 2013; doing 190mph on derestricted German autobahn in a Brabus Rocket; and driving McLaren’s legendary ‘XP5’ F1 prototype. His own car is a trusty Mazda CX-5.

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JOHN T SHEA 18 December 2014


The Outlander PHEV is an utterly unaffordable luxury for many people.
JOHN T SHEA 18 December 2014


"But they won’t have much to moan about when they learn of the S500’s vitals. The 443bhp combined output is as much power as any non-AMG-branded V8 might provide, while the hybrid system’s 479lb ft of torque – available from just 1600rpm – is considerably greater."
Not so. The S500 V8 puts out 450 hp and 516 lb ft.
fadyady 17 December 2014

Good to see

Good to see Mercedes getting in the right gear.