First Drive: Tevva Motors 7.5-tonne electric range extender truck
SECTOR Light truck PRICE £40,000–£60,000 + battery lease GVW 7.5 tonne Payload 2,700kg plus body
The problem with a conventional electric truck is that the weight of batteries required to offer a credible range, would use up almost all the available payload. The answer, according to Essex-based Tevva Motors, is a range extender.
Rather than opting for some form of hybrid drive using the truck’s standard 3.8-litre engine, Tevva has equipped the vehicle with a compact 1.6-litre van diesel from Ford.
The engine is not used to drive the wheels at all. Instead it runs a 74kW generator, that produces electricity stored in two banks of lithium-ion phosphate batteries. These batteries can be charged in three hours on a standard three-phase electrical supply and provide up to 100 miles of electric drive range.
The diesel engine can be used to replenish the energy stored in the batteries while on the move, extending the available range as long as the driver has access to a diesel pump.
Tevva has developed a Predictive Range Extender Management System (PREMS) that can be used to plan the following day’s deliveries and make the most efficient use of the varying energy systems.
“Around 90% of 7.5-tonne trucks are back to base use, so you can upload the route and PREMS will calculate how much energy is used in that day,” said programme manager Richard Lidstone-Scott.
PREMS works out when the diesel engine should be running to charge the batteries while the truck is driving outside an urban environment, to ensure that it can complete its mileage within a low emission zone without having to start the engine.
The engine has three operating modes. There is a low noise setting, where it runs at a steady 1,300rpm to charge the batteries quietly. A high efficiency setting lifts that to 2,000rpm for rapid recharging, while a high power setting will run the engine at 3,200rpm, to provide enough energy to drive the truck in the event of completely depleted batteries.
The Tevva is built using a chassis from China’s second largest truck manufacturer JAC. Around 90% of the vehicle will be constructed in China with the installation of the electrical components in the UK. The truck would then be sold as a Tevva in the UK, and as a JAC in China.
However Tevva is also investigating retro-fitting its driveline into existing working trucks. The company currently has a range-extender prototype under test by delivery giant UPS, based on one of its Mercedes-Benz Vario vans.
So does it work? The answer is an unequivocal yes. Though only the firm’s second prototype the Tevva truck is nicely put together and feels almost production-ready. There are various odd wires and controls in the cab at present, to allow the engineering team to start the engine on demand and to monitor systems, but it’s easy to see a finished product underneath.
Tevva is using an electrically-powered power steering pump and compressor for the air brakes, both of which function on demand to minimise the drain on the batteries. At present a diesel-powered Webasto cab heater is incorporated, though the firm is working on an electric system.
The truck even features a smart DPF for the Ford diesel engine, as its fixed speed operation and lack of transient running allow very accurate exhaust additive dosing. That said, the firm will move to Ford’s Euro 6 1.5-litre diesel by the time a production model is built.
Top speed has been set at 50mph but as with all electric vehicles maximum torque of 1,800Nm is available from standstill, making for rapid acceleration. Regenerative braking means that the driver need hardly use the foot brake in urban driving, extending component life.
Electric only range has been predicted at 100 miles, while customers should see up to 250 miles with a 40-litre diesel tank or up to 370 miles if they opt for a 75-litre tank.
That said of course, long distance work is not the intended use. Being able to run outside the city centre with the generator operating and then slip silently into urban traffic on full electric drive is the truck’s forte.
Tevva is predicting a production price of £40,000-£60,000, plus a battery lease. The company says that an operator covering 150-200 miles per day should see payback within five years on a new truck, though the retro-fit option promises a far faster return on investment.
Though still 24 months from full sales, Tevva is currently looking for a production site.
“We are gearing up for production, that’s how close we are,” said Mr Lidstone-Scott. “We will sell it as a chassis cab, so the operator can put whatever body they like on it. We will make sure there are feeds and mounting points for body builders.
“Even if you only use the range-extender for one mile a day, you will have used maximum mains electricity. Plus you’ll never run out or break down,” he added.
What we think
The Tevva truck combines impressive payload and performance with a comfortable driving environment. If the figures stack up when it hits production, the range extender definitely has a place in urban delivery fleets.