An electric range-extended 7.5-tonner developed by Brentwood-based Tevva Motors, but using a Chinese-built JAC N Series chassis cab, is now undergoing trials. Power comes courtesy of a 120kW/1,800Nm electric motor married to a reduction gearbox that takes the drive to the back axle via a cut-down prop shaft.
The motor relies on lithium-ion phosphate batteries mounted under the cargo bed. Then, acting as a generator and with no link to the transmission, the range extender is a 100bhp 1.6-litre Ford diesel engine sitting beneath the truck’s tilt cab.
Twin 66kWh 350V battery packs can be charged at night from a three-phase 32A mains supply in under three hours, says Tevva. These give the N Series a battery-only range of up to 100 zero-emission miles, although more realistically 50—70 miles in laden working conditions. Use the diesel to boost the battery charge every so often, however, and the range rises to some 370 miles, depending on the fuel tank fitted.
Given the requirement to reduce NOx emissions in urban areas, the last thing anybody wants is for the engine to fire up while the truck runs down the high street. So Tevva has come up with a cloud-based system dubbed PREMS (predictive range extender management system). Operators will send PREMS the vehicle’s route for the day, and the energy requirement is calculated and the range extender programmed to cut in and out accordingly.
Tevva business project manager Richard Lidstone-Scott explains that, typically, the motor cuts in while the truck is travelling along rural dual carriageways at its speed-limited maximum of 50 mph, but it cuts out once the driver gets among the chimney pots. He contends that CO2 emissions from the range-extender are 80% down compared to a 7.5-tonne diesel, with NOx also reduced more than 50% even against a Euro 6 model.
A telematics package also enables the vehicle to be monitored remotely via a web portal – so transport managers can see battery charge and usage as well as key truck temperatures, speed and location. Meanwhile, analytical tools reveal how much CO2 and NOx have been saved.
The DfT (Department for Transport) and DECC (Department of Energy and Climate Change) helped fund the project and Tevva’s technology is currently being assessed by UPS in a Mercedes-Benz Vario in the London area. And Lidstone-Scott says the system is suitable for trucks grossing at up to 18 tonnes, although a larger battery pack would be necessary.
So how much will a 7.5-tonne chassis cab cost? “You’ll be talking £40,000 to £60,000,” says Lidstone-Scott. Against that are claimed total cost of ownership savings of up to 27%, compared with a diesel, he adds. And there are congestion charge savings and government grants. Batteries plus an electric motor spell minimal maintenance costs, but the 1.6-litre diesel requires periodic servicing. Meanwhile, the batteries should last seven to 10 years, says Lidstone-Scott – so will probably be leased.
“If we sell the vehicle as a Tevva using a JAC platform, we’ll probably be able to get it homologated and into production in three to four years,” predicts Lidstone-Scott. “A retrofit package suitable for other trucks will hopefully be available on a commercial basis within the next two to three years.”