Plug-in editions of the new BMW 7 Series executive saloon went on sale in the UK last week. Two versions are available: a long-wheelbase four-wheel drive 740Le xDrive and a slightly shorter 740e with drive to the rear axle alone.
These two new options expand the line-up of plug-in hybrids available from the German manufacturer, which also offers mains-charged editions of its X5 SUV, 2-Series people carrier and 3-Series saloon, as well as the dramatic i8 coupe offered by the BMW i division.
The 740e and 740Le xDrive both feature the same petrol-electric powertrain. A four-cylinder, 2.0-litre engine lives under the bonnet, turbocharged to produce up to 255bhp. It joins forces with an 83kW (111bhp) electric motor integrated into the car’s 8-speed automatic gearbox, providing an overall potential of 322bhp, with 500Nm reserves of torque.
The electric motor alone can provide up to 250Nm of torque from a standstill, helping to enable very brisk acceleration from rest. The 740e can reach 62mph in 5.4 seconds, while the extra driven axle of the 740Le xDrive allows it to reach the same benchmark 1/10th of a second more quickly.
The electric motor can also sustain speeds of up to 87mph without the aid of the engine. Pure electric running can be selected via an eDrive switch on the car’s central console, and BMW quotes an EV range of 29 miles for the 740e and 27 miles for the longer of the two cars.
Both variants feature a 9.2kWh lithium-ion battery mounted under the rear seats, alongside the petrol tank. Only 80% of the rated capacity – 7.4kWh – is available for use before the car will automatically switch into hybrid mode. The driver can also choose to preserve battery power for later use at anywhere between 30% and 100% capacity, which can be useful for zero-emissions urban running at the end of a longer journey.
The battery can be recharged in a little less than four hours using a standard 3-pin socket, while a BMW wallbox will charge at a higher current and take about an hour less.
Mode switches allow the driver to choose between Sport, Comfort and fuel-saving Eco Pro modes as well as a new Adaptive setting, which effectively switches between the various options according to how aggressively the car is being driven.
Like all current BMW 7 Series models, the bodies of the two plug-in variants are built using a mixture of high-strength steel, aluminium and carbon fibre sections. Bonnet, boot and door skins are made of aluminium alloy, while 50% of the aluminium used in structural cast-alloy components is from recycled sources. BMW said waste has also been trimmed by fashioning some of the carbon parts from offcuts of other sections.
According to BMW, weight-saving measures mean that current 7 Series models are about 130kg lighter than their equivalents from the previous generation. This has not prevented the two new hybrid editions from landing in the region of two tonnes apiece, however.
Prices for the 740e start at £68,330 while the longer 740Le xDrive costs from £74,880. Neither qualifies for the Plug-in Car Grant, which applies to plug-in hybrids only when they cost below £60,000 including options.
The two plug-in BMW 7 Series do, however, meet the criteria for low-emissions exemption from the London Congestion Charge. The threshold for this saving is set at 75g/km and both the 740e and 740Le comply with official CO2 ratings of 49g/km and 52g/km respectively.
The two CO2 figures also bring Benefit in Kind rates of 7% and 11% in the 2016/17 tax year, making the plug-in cars particularly attractive for company buyers when compared to diesel 740d and 740Ld alternatives. The diesel cars cost about the same to buy but face BIK percentages in the mid-20s, depending on specification.
The new BMWs also dramatically undercut the Mercedes S-Class 500e plug-in hybrid, which also offers an 11% BIK rate this tax year but costs from £90,165.
The petrol-electric Mercedes is more powerful than the plug-in BMWs, with a 3.0-litre V6 contributing to an overall output of 442bhp and 650Nm of torque. However, it has a shorter 20-mile electric range, slightly worse CO2 rating of 65g/km and weighs roughly 10% more at 2.2 tonnes.
By Lem Bingley