2016 Mercedes-Benz S550e hybrid: what’s the point?

Rear-wheel-drive hybrid S-Class is a hybrid in more ways than one

Published: April 25, 2016, 9:00 AM
Updated: November 23, 2021, 4:06 PM

Mercedes-Benz S550e - Mercedes-Benz S550e hybrid

This test car might be the only Mercedes-Benz S550e on the road in Canada. It’s certainly the first, but it’s a long way from being the last word on electric cars.

The S550e qualifies for a green licence plate in Ontario, which lets it drive in most High Occupancy Vehicle lanes with only one person inside, because it’s a plug-in hybrid electric vehicle. It even says so in lettering at the bottom of the rear doors – a surprising lack of discretion for Mercedes. Not to worry. The sticker can be peeled off if you don’t like it.

It might help explain why the car can move silently, powered by pure electricity for as long as the lithium-ion battery can hold enough charge.  Which, it turns out, is not very long at all. The $133,250 Benz might cost Tesla-style money, but it’s more like a first-generation Chevrolet Volt when it comes to the range of its battery.

Inside, the big Benz is no Volt. It offers everything an S-Class flagship can provide, with no compromise. It’s only available as a long-wheelbase (LWB) model, so there’s plenty of leg room for everyone. There are also massaging seats, an impressive digital display that fills half the width of the instrument panel, and a suspension that floats over ruts and bumps. It has all you need to be completely isolated from the annoying distractions of outside.

The price

You can get all this in a regular S550, which starts at $110,700, or $119,500 for the LWB model, but the 550e is no regular car. It’s Mercedes’ first production plug-in hybrid, and its base price is $117,300 before adding all the options of my tester – cheaper than the 550 LWB, despite the additional technology.

However, it’s not that simple a comparison: the 550e is not a 550 with an extra electric motor. It gets its name from its similarity in performance with the V-8-powered, 4.7-litre 550, but its gasoline engine is the 3.0-litre turbocharged V-6 that’s found in the S400, which retails for $102,600.

It’s not an apples-to-apples comparison between either of the conventional Benzes and the S550e. For a start, those two regular models are “4MATIC”, which is Mercedes’ term for all-wheel drive. The S550e is rear-wheel drive, because there just isn’t the physical space to fit the hybrid technology alongside the AWD differential.

In Canada, the only other RWD S-Classes are the sportiest sedans, coupes and cabriolets, which don’t have equivalent AWD models. South of the border, however, the AWD option costs an extra $3,000 U.S. on equivalent models, which is about $4,000 Canadian.

So all this means you’re paying almost $19,000 for the additional technology over the S400, but for that price, you get a long-wheelbase model (worth almost $9,000 extra, don’t forget), better performance, better fuel consumption and a clear environmental conscience. Whew! You also qualify for a provincial subsidy if you live in Ontario, Quebec or B.C.

On the downside, there’s 68 litres less space in the trunk, but it’s still big enough for at least a couple of golf bags. So, is it all worth it?

The performance

First, the performance, because if you’re spending this much money on a car, it should be fun to drive. The S400, which is the base model in Canada, makes 329 horsepower and 354 lb-ft of torque, while the S550 makes 449 hp and 516 lb-ft.

The hybrid S550e can use its electric motor to boost the performance of the gasoline engine, and the two combined create 436 hp and 479 lb-ft of torque. That’s not quite up there with the 550, but the maximum torque of the hybrid kicks in at just 1,000 rpm and holds up to 4,750 rpm, compared to a much narrower torque band of 1,800-3,500 rpm for the S550.  More than fair tradeoff.

Zero-to-100 km/h takes a claimed 5.2 seconds. Compare that to 4.8 seconds for the S550, and 6.1 for the S400.

That’s enough numbers for now. Suffice to say, when you’re cruising along the highway, the S550e can overtake with confidence and ease. On a back road, set the drive mode to Sport and forget about saving fuel – it will use the electric motor only for extra power. Like any S-Class set to Sport, it also quickens the throttle response, firms the suspension, and adjusts the transmission shift points.

The hybrid weighs 206 kg more than the conventional S550, which is the equivalent of always carrying three adult passengers. It’s not supposed to be a track car though, and its performance is far from disappointing.

So let’s move on to the fuel consumption, and the magical all-electric driving.

Pure electric

I plugged in the car overnight to my garage’s 110V power outlet and the battery was 100% charged in the morning. If I’d plugged it into my washing machine’s 220V outlet, Mercedes says it would have fully charged in about four hours.

That charge was good for 34 km of pure electric driving, according to the on-board readout. So I started the car on a slightly frosty morning and took my kid to school. It was a 5.5 km round trip, and when I got back home, the range estimator told me I had only 14 km of electric driving left. Hmmm. I didn’t plug it back in because electricity is more expensive during the day.

Halfway through the morning, I retrieved my sunglasses from the car. When I opened the door, there were lots of whirring noises from under the hood that kept whirring after I locked it all up. When I got back in after lunch, the range estimator told me I had just six kilometres of electric driving left. I went into town – two kilometres – and the battery was drained to 20%, at which point it stops powering the motor.

That first day, a fully-charged battery gave me a total of 7.5 kilometres of electric driving, and then the car became the equivalent of an S400.

The next morning, after another night of charging, I got in the car for a similar frosty start and the range estimator said I had 30 km of electric driving available. It based this on the previous day’s experience. I turned off the heated seats and turned down the cabin temperature and switched off the LED headlights, but even so, I still had just 14 km of range left after the short school run. Hmmm again.

Of course, getting the car to operational temperatures causes a lot of that power drain. Like any electric car, it can be pre-warmed, or cooled, when it’s still plugged in, either by presetting it or just switching it on through a smartphone app. Clearly, if you don’t do this, you’ll pay the price in electric range.

Light on the gas

Over its 426 km of use from brand new, before I collected it, the S550e had returned an average consumption of 10.0 L/100 km according to its readout. That included 76 km of driving with the gas engine turned off, either powered by electricity or just sailing power-free on flat or downhill stretches of highway. Its official combined rating is 9.7 L/100 km.

In comparison, the shorter S400 has an official combined consumption rating of 10.8 L/100 km, and the LWB S550 has an official rating of 12.5. Again, these numbers can’t really be placed against each other because your consumption will change drastically if you travel short city distances instead of long highway stretches.

But the S550e is not about saving money. My head hurts trying to make these comparisons, and yours probably does to, when none of it is really necessary. After all, if you drive an S-Class Mercedes, the potential for a few hundred dollars in savings, or even a few thousand dollars, is irrelevant. It’s about using as little fuel as possible, and creating as few emissions as possible. This helps Mercedes hit its government-set fleet consumption targets, and helps you sleep at night.

In fact, Mercedes claims that “over the entire lifecycle, comprising manufacture, use over 300,000 kilometres and recycling, clear advantages result compared with the S550. External charging with the European electricity mix can cut CO2 emissions by some 43% (35 tonnes). Through the use of renewably generated “hydro electricity” – like that in Quebec and southern B.C. – “a 56% reduction (46 tonnes) is possible.”

Smart software

You can do your bit as a driver to save fuel by switching the S550e’s drive mode to Economy-Plus, which is just the turn of a dial on the centre console. Doing this activates the “haptic accelerator pedal,” which kicks back gently when it thinks you should ease off on the gas.

The pedal is smarter than you, too. Not only does it use radar to know you’re approaching a car from behind, but it knows you’re coming to an intersection, or that you’re about to start driving on a downhill slope. The computer even knows that your route is taking you into the city, so it will conserve the electric charge until you reach more congested streets, where the electric motor is better suited for driving than the gas engine.

Not only that, but when you brake normally, you don’t actually activate the brakes at first. The S550e will use the electric motor to slow things initially, which harvests the braking energy to help it recharge.

Like other plug-ins, you can set the car to drive completely in electric mode while the battery has sufficient charge, or in regular hybrid mode, or in E-Save mode. This avoids using electric power unless you mash the haptic throttle pedal to the floor – which I did a few times, just to show it who’s boss.

There’s even an E-Charge mode, like on the Porsche Panamera and Cayenne E-Hybrids, which will charge the battery while driving. I fully recharged a battery that was drained to 20% by driving on the expressway for 50 kilometres. My fuel consumption increased to 12.1 L/100 km in that distance, so it cost me an extra litre of fuel, but I then had a fully-charged battery in a warmed-up car for 30 km of pure electric city driving.

So, considering that extra litre, effectively I got 3.33 L/100 km for that 30 km. I think. Too much math! At any rate it was was much easier than plugging in for four hours.

The end result

In the end, all of this mind-numbing technology isn’t really going to save you a lot of fuel – you’d be far more environmentally responsible if you take the bus, or buy a Honda Civic and donate the extra $100,000 to Greenpeace – but it does cut down on your footprint if you want to drive a large and luxurious sedan. It also helps Mercedes to develop fuel-saving technology for less expensive models.

And most importantly, you get to drive one of the very first S550e models in Canada, sailing silently and alone in the HOV lane past the riff-raff on their way to work. For a while at least.


Model: 2016 Mercedes-Benz S550e

Price: $117,300 base; $133,250 as tested

Type of vehicle: RWD full-size luxury sedan

Engine: 3.0L turbocharged V-6 with hybrid electric motor

Power/Torque: Gasoline engine – 329 hp / 354 lb-ft of torque; Electric motor – 114 hp / 251 lb/ft; Combined – 436 hp / 479 lb-ft.

Transmission: 7-Speed automatic

Fuel consumption (L/100 km): 11.1 City, 8.1 Hwy., 9.7 combined

Competition: Porsche Panamera E-hybrid, Tesla Model S