2015 MERCEDES-BENZ S500 Plug-In Hybrid Review

For what it’s worth, the Mercedes-Benz S-Class isn’t the type of vehicle to be valuated in black or white, but in a widespread spectrum of shades of grey.

If you associated the latter wordplay with E. L. James’ 50 Shades of Grey, I’m sorry to break it up to you like this, but the human eye is said to be able to distinguish only around 30 shades of grey.

Moving on beyond this random fact, here at autoevolution we’re no strangers to the W222. We reviewed the sixth-generation of the German automaker’s crown jewel in three guises: the S500 long wheelbase, the S63 AMG 4Matic and the S500 4Matic Coupe (C217), but time has come for us to get acquainted with the S500 Plug-In Hybrid and its eco-boastfulness.

First thing you need to know about the PHEV is that although labeled S500, you’re not dealing with a 455 horsepower twin-turbo 4.7-liter V8 as you get on the non-hybrid S500. Curiously, the three-pointed star shoehorned the 3-liter twin-turbo V6 from the S400 under that long hood.

This force-fed six-cylinder is part of the M276 family of V6 motors and offers 333 HP (328 ponies in American money) and 480 Nm (354 lb-ft) of torque. The engine choice is even more curious if you take into consideration that the Lexus LS 600h L is equipped with a 5-liter V8.

Additionally, the hybridized LS boasts all-wheel drive, while the 2015 Mercedes-Benz S500 Plug-In Hybrid is rear-wheel drive only. So how does the PHEV rank against the other three S-Class variants we’ve tested in the past?

It’s hard to pinpoint its place in the food chain, but if you’re a music connoisseur, I’ll be much obliged to make some musical analogies for you.

The S500 LWB is as smooth as the Getz/Gilberto jazz-bossa nova album and the S63 AMG 4Matic is as big a ruckus as The Sex Pistols’ Never Mind the Bollocks masterstroke. On the other hand, every time I see (and hear) the S-Coupe, Richard Wagner’s glorious Ride of the Valkyries starts ringing in my head.

For starters, this whisper-quiet luxobarge is as tight as a drum or, on this occasion, as tight as the infamous Miles Davis sextet ensemble. While Bill Evans gives subtle piano nuances, the hard bop style of Cannonball Adderley and Davis’ cool approach to playing the trumpet add up to a perfect blend of jazz music idiosyncrasy.

As analogies, these elements are equal to the perfect S-Class variant currently produced, but there’s a catch with my choice of musicians - more than half of the sextet were addicted to hard drugs, a habit that rendered them a bit on the counterproductive side of things on many occasions. In the S500 PHEV’s case, the same effect can be noticed if you concentrate hard enough and look beyond the straightforward luxury and hi-tech.

At first glance, the exterior aesthetics of the PHEV are a carbon copy of the S500 long wheelbase, except for only two details. Other than the Plug-In Hybrid lettering on the boot lid and the charge port door under the right-hand side tail lamp, every other visual detail is shared between the two W222 models.

On the inside, we’re invited by a familiar-looking cabin. No, your eyes aren’t deceiving you. In a similar manner to the exterior, the interior of the Plug-In Hybrid features a single difference over the Mercedes-Benz S500 LWB - a mere button.

The raise/lower ride height button of the S500 LWB’s center console has been moved to the right-hand side of the Mercedes-Benz Comand infotainment system’s rotary dial, making way for a button that lets you choose between the plug-in hybrid system’s four driving modes.

We are offered with Hybrid, E-Mode (electric power only... sort of), E-Save (the fully charged battery is reserved to be able to drive on electric power alone later) and Charge (battery is charged while driving). Though E-Mode will see the V6 power up to life if you put your foot hard down on the loud pedal, the most electric-oriented driving mode of the PHEV artificially makes the throttle pedal stiffer to press.

It’s only when the grey E-Drive bar on the lower left side of the digital rev counter turns wholly grey that the twin-turbo V6 tower-of-power starts singing its internal combustion song.

While on the subject of E-Mode, it is now time to talk about what makes this Merc an S500 Plug-In Hybrid. No points will be awarded to those that have thought of a jumbo battery pack and an electric motor.

Whereas the S400 Hybrid and S300 BlueTEC Hybrid are autonomous hybrids charged when you coast or brake, the S500 Plug-In Hybrid is given ten times the energy capacity and the possibility to charge it from an external source.

With 85 kW (115 HP or 114 American ponies) and 340 Nm (251 lb-ft) of torque, the electric motor is no slouch. Depending on how careful you are at feathering the throttle, available zap of the 8.7 kWh battery and the road you’re driving on, it’s possible to run in full-electric mode at speeds of up to 140 km/h (87 mph).

In theory, the three-pointed star brand promises an all-electric range of 33 kilometers, but we’ve been shown 34 km (21 miles) with the battery charged at 100 percent. However, real-world driving scenarios will see those 34 km cut down to around 20 km (12 miles) at best if you drive exclusively in the city... like an octogenarian.

About that 396-volt lithium-ion battery pack, the W222’s 510-liter (18 cuFT) available cargo capacity is watered down to 395 liters (13.9 cuFT) because the battery sits right on top of the rear axle. At this point, I feel obliged to answer a question: 480 Nm + 340 Nm equals 820 Nm (604 lb-ft), so why is the combined torque of the ICE + electric motor rated 650 Nm (479 lb-ft)?

It’s simple to explain - the combined torque of the powertrain has been electronically limited because too much twist for the rear axle isn’t for the fainthearted. In addition to this, play the video below and hear how hard the rear axle is keeping those 650 Nm (479 lb-ft) in check. If it were for 820 Nm (604 lb-ft), I have this gut feeling that the rear axle would call it a day...

Due to the extra weight on the sub ensemble, the 2015 Mercedes-Benz S500 Plug-In Hybrid is tail happy too, especially at high speed, even with the electronic driving aids turned fully on.

It’s not something you should worry about if the car is driven normally, but when you pick up the pace, there’s this feeling a tank slapper will be on the menu if you muscle the steering wheel with too much bravado. All in all, all-wheel drive would’ve been better suited for the S500 PHEV.

You know how most auto manufacturers claim enthusiastic fuel economy figures based on the testing procedures of the New European Driving Cycle (NEDC), right? Well, the S500 PHEV is rated 2.8 l/100 km (84 US mpg / 101 UK mpg).

Outside the NEDC’s laboratories, Mercedes’ newest hybrid luxobarge managed 11.6 l/100 km (20.2 US mpg / 23.3 UK mpg) at an average of 130 km/h (80 mph). You’ll be hard pressed to do better than 6.9 l/100 km (34 US mpg / 40.9 UK mpg) in the urban jungle in Hybrid mode.

After many calculations, our combined average stood at 8 l/100 km (29.4 US mpg / 35.3 UK mpg), which is highly impressive for such a heavy and luxurious machine. And don’t go laughing at its eco-friendly credentials either.

The most impressive aspect of the powertrain is how quiet the 2015 Mercedes-Benz S500 Plug-In Hybrid is in E-Mode. It’s a genuinely pleasant (and eerie) experience to find yourself behind the steering wheel of an S as quiet as this one.

That’s about enough jibber-jabber on the go-faster and fuel economy, so let’s move on to other stuff worth talking about. Before that, I want to tell you that from the inside, the twin-turbo V6 engine sounds throatier than the twin-turbo V8 of the S500 LWB. Both the induction and exhaust noises have a fuller, richer tone.

Our smooth operator is laden with the best the optional extras list has to offer. In Germany, the base price (including VAT) for the Mercedes-Benz S500 PHEV is €109,777. For that money you get a lot of toys and five seats, but our car has four sofas and so much kit that the price now stands at €161,441. Unfortunately for the potential customer from the US, Mercedes has yet to put a price tag on its poshest hybrid ever.

Eventually, the Mercedes-Benz S500 Plug-In Hybrid will arrive stateside with an estimated price north of $120,000. If you can manage without the perks of internal combustion, your other choice could be the all-electric and super fast-accelerating Tesla Model S P85D, which goes for $98,170 including all the incentives.

Though it’s hard to tell from our B&W photo gallery, the cabin is awash with designo Deep Sea Blue and Silk Beige Nappa leather.

Another option that ups the visual ante is the AMG Sport Package that brings goodies such as the wood and leather-wrapped sports steering wheel and poplar wood trim on the dashboard and interior door panels.

I know this is a subjective point of view, but the poplar is, typically Mercedes-Benz, too glossy for my liking. Alas, you’re not able to appreciate the grain as you can with more porous wood you get on Bentleys and Rolls-Royces.

Similarly annoying is the German automakers’ obsession with not adopting touchscreen tech. The Mercedes-Benz Comand unit isn’t hard to get accustomed to, but that 12.3-inch display would be better suited for tactile technologies.

Due to the ambient lighting, sheer size and the well-being offered by the optional Seat Comfort Package seats and the Energizing Massage function, chances are you’ll mistake the S500 PHEV’s accommodating interior for a crossover between a five-star spa resort and a vodka bar.

Ritzy isn’t a suitable word to describe the feeling onboard this thing. But there are three niggles that need to be mentioned about the ergonomics, regardless of all the imperialness.

The S500 PHEV is enhanced by Mercedes-Benz’s Airmatic suspension with continuously variable damping, but the system could use some fine-tuning for the rear passengers’ sake. The S500 long wheelbase is also a four-seater with Airmatic, but doing the technicolor yawn wasn’t on the S500 LWB’s list of drawbacks.

Then there’s the HVAC unit up front. Every time you close the ashtray, you’ll also hit the AUTO button or the MAX windscreen demister button. Don’t ask... An array of touch-sensitive buttons could’ve prevented this fault from happening. Last but certainly not least, I have to address people with lower back pain.

Despite being the most sumptuous and expensive seats available, the Mercedes-Benz S500 Plug-In Hybrid’ seats aren’t a lap of luxury as immersive as other seats in the full-size luxury sedan segment. The cushioning is regal and the “fit for a king” label applies for all four occupants, but I never got the feeling that “yes, this is the best car seat my bum has ever met.”

The massaging function is lovely as a plaything, but I feel that the most stimulating massaging programs available aren’t up to the job of soothing someone’s tense back muscles.

Oh, did I forget to mention that there’s a 230V socket hidden deep inside the rear center armrest? This feature is hugely useful for the proverbial Russian oil tycoons that need to check the stock market evolution of crude oil around the clock from their fancy ultrabooks and iPads.

Being an oil magnate is a 24/7 job, so these “poor souls” will eventually get thirsty from all the stress that comes with such a vocation. In this regard, the rear passengers have two cup holders that can either cool or heat their water bottles, espressos, orange juice, you name it.

To sum the 2015 Mercedes-Benz S500 Plug-In Hybrid up nicely, I’m having lots of trouble trying to think of a better full-size sedan recipe that interweaves top-class luxury, performance and eco-consciousness as well as this Teutonic knight. As noted beforehand, you can’t enjoy an S-Class by labelling things in black and white.

Similarly to Miles Davis’ Kind of Blue-era sextet, there are plenty of good points enhancing the S-Class experience, as well as a number of bad points that leave you longing for more pizzazz.

Thing is, Kind of Blue is the best-selling and most important jazz album ever recorded. The Sonderklasse in S500 Plug-In Hybrid guise also has all the right makings to tower above its hybridized peers, including the slightly bland and terribly unemotional Lexus LS 600h L.

If I had the money and the need for such a car, would I buy one? It’s a hard question to answer, but then again, Miles Davis and jazz as a musical genre may not be to everyone’s taste...