Putzmeister eMixer - On silent soles across town, country, motorway

The white-painted Putzmeister truck mixer moves almost silently into Darmstadt's city centre. To the left and right of the main road are tall apartment buildings, hotels and commercial buildings. Tens of thousands of cars per day, plus construction site noise and public transport: a highly stressful acoustic experience for residents. And when a 32-tonne diesel truck mixer navigates through the city centre, it is an additional burden. But this time everything is different: the Putzmeister iONTRON drives in a refined and restrained manner. Truck driver Valentin Kiefel has been transporting concrete for 15 years, but this experience is new for him too: "The car is so quiet, just incredible. I can hear the tyres on the country road. Even the neighbouring cars at the traffic lights are louder than me. Look, I have the radio turned down really low, yet I can hear the music."

The driving performance is also a positive surprise, explains Valentin Kiefel: "The power is incredible. I don't feel any difference whether I drive off with or without concrete. The electric drive is insanely strong." In fact, the acceleration, for example at traffic lights or after a roundabout, is comparable to a passenger car - no usual "jerking" due to the gear shift when starting. The driving comfort surprises every truck driver.

The Putzmeister iONTRON approaches the construction site. You can hear children's voices from the playground - elderly ladies are chatting right next to the site fence - no noise, no hubbub. Only a soft whirring noise reveals that a new technology is on the way here. And of course the stickers on the side and rear: 100% electric - the Putzmeister P9G truck mixer is on the road in Germany.

Since May 2023, Putzmeister has been on a Europe-wide tour with the eMixer. It starts in southern Germany: from Aichtal via Mannheim, past Frankfurt to the A7 motorway, on to Erfurt, followed by Sauerland, East Westphalia and the Rhineland ... The aim is to inspire confidence: The machine drives - super - quietly! Not a prototype - but a fully developed construction site vehicle. The wheel formula is quite classic: 8x4 with two steering axles at the front and two driven rear axles. The P9G truck mixer body is completely Made in Germany - assembly takes place at the Putzmeister factory in Aichtal. With a nominal volume of 9 m3 and a water capacity of 10.2 m3, the drum capacity corresponds exactly to a standard diesel mixer. Due to legal requirements, the iONTRON is allowed to load around 17 tonnes. Therefore, the real transport capacity is about 7 m3 of concrete.

The chassis comes from the Putzmeister parent company SANY, the third largest construction machinery manufacturer in the world. The energy is stored in ten battery packs of 35 kWh each, which are well ventilated and housed in a separate enclosure behind the driver's cab. The on-board voltage is 600 volts, the battery capacity 350 kWh. That is roughly equivalent to the calorific value of 36 litres of diesel. And the range? 

Driver Valentin Kiefel draws a first balance after four concrete tours in the city centre of Darmstadt: "Normally, a truck mixer consumes 45 to 50 litres of diesel per 100 kilometres. In the new vehicle, the consumption is displayed on the driver's screen: "We consumed 171 kilowatt hours today, with 110 kilometres driven and 25 cubic metres of concrete delivered. That's incredible, no diesel mixer can do that." For comparison: 171 kWh correspond to the calorific value of just under 18 litres of diesel. 

Due to recuperation, braking is rarely necessary. Valentin prefers to drive in stage 1 or 2, up to 5 stages are possible. Before roundabouts or red lights, it is sufficient to step off the power pedal - the vehicle "brakes" harmoniously and the battery is recharged at the same time. A cycle. The driving style is refined, quiet, pleasant.

The outside temperature that day is around 18 to 20 degrees Celsius. There is no rain. Charging between trips is not necessary: the eMixer returns to the mixing plant with exactly 51% charging capacity, with 110 kilometres driven. Valentin Kiefel: "The mixer could easily have done one or two more tours today, but that's enough for today." 

For comparison: The day before, the motorway overpass from Aichtal (south of Stuttgart) to Gernsheim took place, and the mixer had a battery capacity of 46% after about 180 kilometres driven. With restrained driving and a free stretch of road, an empty run of more than 300 km is possible. 

Kevin Eichele is responsible for the market launch of the all-electric mixer at Putzmeister. He points out: "The maximum kilometres depend on the outside temperature, the gradient, the driving style and the construction site situation. When driving empty, we reckon with a maximum range of over 300 kilometres, and that's without charging in between. At work, the real range is closer to 150 kilometres per day. We will prove these values in real-life use in the coming weeks." 

The charging process is also clean: after cleaning and spraying off the residual concrete deposits, the eMixer moves almost silently to the mobile charging station. The charging station is located directly under the driver's cab, protected behind a black flap. Valentin Kiefel gets out of the cab, sets the start button from 0 to 1, waits briefly for the signal and then plugs the CCS2 connector into one of the two charging sockets below the battery. The mobile charging station draws its power from a 63 amp plug connected to the transformer station at the site. If the grid allows a higher output, charging with two plugs is also possible. 

At 35 kW charging power, the battery charges at approx. 10% per hour. Depending on the remaining battery, the charging time is a maximum of 10 hours - a whole night. At the start of the shift at 6 a.m., the mixer is fully charged. No diesel smell on your hands - no loud driving noises - so relaxed can the end of the working day begin.