Mercedes-Benz has ramped-up the race towards heavy-duty electric trucks by putting a fleet of fully-electric eActros trucks to work with German customers.

Ten of the battery electric trucks, with a 200-kilometre range and a gross vehicle weight ranging between 18 and 25 tonnes, are expected to be in service by this month, in widely-varying work.

They'll run in the fleets for 12 months, then be shifted on to another 10 Mercedes-Benz customers for a further year's operational testing.

The eActros and its testing programme is part of a 2.6 billion Euro investment by Daimler in its trucks division in the next two years, with a heavy focus on electric vehicles, connectivity and autonomous driving.

The aim of the testing programme, says Mercedes-Benz, is to prove the eActros' "everyday feasibility and economic efficiency under real-life conditions" in urban environments, with a view to the etrucks going into series production in 2021.

The eActros uses the frame of the standard, diesel-engined Actros – with a ZF AVE 130 drive axle "that's already proved its worth" in Merc hybrid and fuel-cell buses.

The drive system comprises two three-phase asynchronous electric motors that operate with a nominal voltage of 400 volts. They generate an output of 125kW each, with maximum torque of 485Nm each. Gearing ratios convert this into 11,000Nm each, which Mercedes-Benz says delivers "driving performance on a par with that of a diesel truck."

The power is stored in two lithium-ion batteries with an output of 240kWh. Again, they've been proven in electric buses: "Synergies within the group, like these, allow us to pool our experiences, shorten development times and, of course, also save costs," says Mercedes-Benz Trucks head Stefan Buchner.

The batteries are located in the frame area and under the truck, all shrouded by steel housings to protect them from collision damage.

Discharged batteries can be fully recharged within three to 11 hours, assuming what Mercedes-Benz terms "a realistic charging capacity of 20 to 80kW."

The eActros began life as a heavy-duty electric urban distribution truck concept, unveiled in 2016. The subsequent feedback on the technical feasibility of building such a vehicle was "positive, across the board – from the general public, politicians and customers," says Merc.

A number of technical and economic issues "remain outstanding" before it goes into production, it adds – "key among them the range and cost of the batteries, but also the infrastructure required for their use as part of customers' commercial fleets."

The testing, says Daum, "will enable us to establish just what remains to be done, in terms of technical matters, infrastructure and service, to make our Mercedes-Benz eActros competitive."