TAXING QUESTIONS ABOUT THE MERCEDES C350e PLUG-IN HYBRID

I have always wanted to drive an electric vehicle. I had always imagined it would be an eerie experience driving along in almost near silence with a good smooth shove from the torquey electric motor. Well, I still haven’t driven a full electric-only car but last week I came close, in the form of a Mercedes C350e Sport plug-in hybrid saloon. I have driven a couple of Mercedes hybrids before but both were diesel hybrids and neither were plug-ins. They didn’t give much clue as to what it is like to go electric as they only allowed limited use of the battery. Accelerate gently (and quietly) to 20mph and that’s your lot – the diesel then cuts in.

Driving a new Toyota Auris hybrid estate to Merseyside in January, I had a slightly better impression. As well as the initial acceleration, I managed to cruise briefly along an urban road at 40mph. However, the slightest tickle of the accelerator and in came the petrol engine. I did manage a reasonable 58mpg on the long, steady motorway journey though. Close but not quite as good as a typical family-sized diesel.

There is a big difference between the Mercedes and Toyota hybrids though. The Mercedes all had plenty of performance whereas the Toyota was about as lively as a snail with a hangover. I have not driven many cars (or even vans) which feel so sluggish accelerating from, say, 50 mph to 70mph on the motorway. That said, it is of course unfair to compare the Toyota to the much more expensive Mercedes. But petrol-electric hybrids may be the medium-term future if the authorities decide to take punitive financial measures against diesels and not everyone will be able to afford the likes of a Mercedes. Until Marty McFly and Doc Brown develop the flux capacitor and small-scale nuclear reactor to the point where electric-only cars are truly practical (feeding on banana skins and other household waste), it may be Back to the Past for current diesel owners who are used to the economy and performance of a modern diesel engine. For a lot of private buyers, a compromise on performance may become the order of the day if the only realistic option becomes one of the humbler petrol hybrid offerings, such as the Toyota. Incredible to think that diesel cars were thought of as noisy and slow a couple of decades ago.

Back to the Mercedes C350e. A seven speed automatic gearbox, two litre turbo-charged petrol engine with 211hp and an electric motor with 82hp which all adds up to, er, 279hp according to Mercedes’s own figures! The interiors of current Mercedes are really classy and this C-class was no exception – lots of brushed aluminium and high gloss black on the dashboard and leather seats.

I had to take this C-class demonstrator from Leicester to Derby and pick it up again two days later. The car’s sat nav took me on A-roads: skirting Ashby-de-la-Zouch, then north up through the pretty village of Ticknall and across the amazing and ancient Swarkestone Bridge. Much more interesting than the M1 motorway and the Mercedes was a pleasure to drive over this varied route. The battery pack (larger than in the non-plug-in C-class diesel hybrid) adds a lot of weight but the C350e still goes round corners without drama and with plenty of grip. It is quiet even when the petrol engine cuts in, which it does with a very slight nudge. Not imperceptible but almost.

The electric motor frequently did all the work on its own. It was very strange watching the needle on the rev counter drop like a stone to zero as the petrol engine closed down when I was cruising along. Then I was left with that eerie experience mentioned at the beginning of this post – near silence except for a bit of road noise. I don’t know why but this was really satisfying and I was able to cruise at 50 – 60 mph on battery alone for some decent stretches. So with the electric motor seeming to do its fair share of the work, I couldn’t have used much fuel, could I? Actually, the car managed, erm, 36.6mpg. Compared to its official combined figure of 134.5mpg. And I was driving very steadily!

Two days later and I was determined to do better when I picked the car up to return it to Leicester. The gentleman who had been trying out the car said he liked it very much but commented on how the fuel gauge had dropped alarmingly. As a result, it was very low on fuel and had only a 12% battery charge. I was beginning to wish I had slipped a couple of AAs in my bag just in case. The trip computer gave a range of 46 miles and I had 30 to go. Now there’s a challenge. Could I get back comfortably and even increase that margin of 16 miles?

Shortly after leaving Derby, I tried going to full electric-only mode but the car wouldn’t let me, presumably because the battery charge was too low. However, all was going well until I was about 10 miles from my destination. Apparently I still had a range of 32 miles – great, I should now be able to get there with a range of 22 miles to spare. Then the range figure suddenly disappeared to be replaced by a red petrol pump! The fuel  gauge itself now had one small illuminated segment flashing on and off. Interesting. Had the car now decided that the computed range was not to be relied upon? I still had one ace up my sleeve though: electric-only mode. By now the battery charge was up to 17%. I was able to switch to full e power and cruise along for a couple of miles, even getting close to 70mph on a stretch of dual carriageway. This was a very novel and enjoyable sensation – a glimpse of the future perhaps. As I reached the outskirts of Leicester, the car announced that e-only mode was no longer available and the battery charge was down to 10%. I then spent the last few miles trying to eek out the most from the electric motor as I progressed through the suburbs and then the city itself. Negotiating roundabouts and traffic lights, I would accelerate gently (the car using the petrol engine if necessary), then ease off to allow the electric motor to take over on its own. I was able to keep the available battery charge reasonably constant because slowing down for roundabouts or traffic lights usually added 1% to the charge. Eventually – phew – I made it and recorded a passable 48mpg. I suppose that was not bad for a car capable of 0-60mph in 5.9 seconds and a limited top speed of 155mph. However, it took a certain amount of concentration to achieve that figure and all at a very modest pace (the 30 miles took me almost an hour and that was not because of any significant traffic).

So, what do we learn from all that? In short, cars like the Toyota are making a valiant attempt to match the economy of diesels but the Mercedes C350e is not really about saving fuel (or the planet) at all. OK, if you plugged it in every night and had a shortish commute, you may be able to get a decent return for each gallon of unleaded (the official electric-only range on a full charge is 19 miles). No, what this car is all about is going fast and saving tax. Lots of it. In the UK, the vast majority of C350e customers will be company car drivers. In the forthcoming tax year, choosing a C350e over a cheaper diesel C-class (say, a C250d Sport auto) will save a 40% taxpayer over £2000 in income tax due to the C350e’s very low, official CO2 emissions (48g/km). Not bad. Way more than enough to pay for the extra fuel – that’s if the company car driver actually has to pay for his or her own fuel. A lot of company car drivers entitled to a £40,000 company car are probably high enough up the corporate ladder to get fuel for private use paid for by their employer. Due to those officially low CO2 emissions (which are as realistic as the official 134.5mpg), the C350e scores massively here as well when it comes to income tax on free fuel. And here’s the irony – will a company car driver entitled to free fuel have any incentive to plug into his or her own domestic electricity supply?!

Colin

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6 thoughts on “TAXING QUESTIONS ABOUT THE MERCEDES C350e PLUG-IN HYBRID”

  1. Colin, I think we must be living in parallel universe! You just read about a Fleet Air Arm pilot, whilst I read about a Vickers Test Pilot. You just tried a Hybrid Merc, and for the last 6 days I’ve done my first 750 mile sina Hybrid BMW 225Xe (and loving it). Post to follow when I’ve had time to take a few photos….

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