As an innovation-driven brand, Mercedes-Benz has always focused on developing new drive concepts, and that applies to both passenger cars and commercial vehicles. A glance back into the past: forty years ago, Mercedes-Benz AG, as it was called then, presented the 307 E to an international audience. Initially, the experimental van was on display at the Envitec environmental trade fair in Düsseldorf (11 to 15 February 1980) and then in London at the Drive Electric ’80 exhibition (13 to 20 October 1980). One thing was certain: its suitability for everyday use was far removed from today’s production vehicles such as the eVito and eSprinter, but it provided important technical insights and practical knowledge.
“Daimler-Benz AG has developed the Mercedes-Benz 307 E electric van, based on the model series T 1 van. Attention was paid to the smallest possible deviations from current series production in order to keep manufacturing and operating costs within narrow limits.” This was how the Mercedes-Benz concept vehicle was presented in the press information on 31 October 1980. However, the 307 E was not the first electric van under this brand name. As early as 1972, Mercedes-Benz had presented the LE 306, which was also an experimental vehicle. A total of 60 of these were built and, by 1979, that small fleet had covered 900,000 kilometres. One result of these experiments was that the battery-change technology tested in the LE 306, among other things, could be dispensed with for the intended application of using the electric van in urban traffic.
The 307 E was developed on the basis of the TN van model series, also known as the T 1, which debuted in 1977. The Federal Ministry of Research and Technology (BMFT) funded the project. In order to reduce manufacturing and operating costs, the 307 E had simplified control technology for the electric drive, which at the same time required only minor deviations from the standard 307 D van with a wheelbase of 3,350 millimetres. The battery was located underneath the vehicle floor between the front and rear axles and had a rated voltage of 180 volts. Two battery rows providing 90 volts each were installed. The batteries were easy to remove downwards and install by means of an integrated lifting device and with standard workshop lifting gear. The load compartment was no less voluminous compared to vehicles with combustion engines. With a payload of 1.45 tonnes and a range of 65 kilometres at a steady speed of 50 km/h, the 307 E was predestined for urban distribution jobs. Four different types of electronic drive control and power transmission were tested, for example the battery switchover version with electronic field control, combined with a hydrodynamic torque converter. The direct current shunt motor had an output of 30 kW. The maximum speed achievable was 70 km/h and the maximum gradeability was 20 per cent. In the 307 E, Daimler-Benz researchers and developers tested not only drive concepts but also other technology, such as the “route planner”. This forerunner of the navigation system provided information for potential route changes, such as traffic jam reports.
Large-scale testing in two large towns
From 1981 until the end of 1983, two large-scale tests were carried out using 32 electric vans. The Federal Ministry of Research and Technology (BMFT) tested ten 307 E vans in Berlin as part of the “Alternative Energy for Road Traffic” research project initiated by the Ministry. The German Post Office (Deutsche Bundespost) carried out the second large-scale trial over five years in the parcel delivery service with 22 electric vans in Bonn. These two practical trials made it clear that transport jobs can, indeed, be taken on by electric vehicles in conurbations. Due to their performance and operational safety, the electric vans compared favourably with contemporary production vehicles with combustion engines.
However, the key issue with electric vehicles at that time was the battery technology available. “Although their range is sufficient for the task at hand in inner-city areas, the high maintenance requirements and unsatisfactory service life of lead-acid batteries lead to disproportionately high operating costs,” stated the press release of October 1980. It continued: “Even though promising further developments can be expected in the near future, it should be noted that the expensive electrical components will lead to higher operating costs compared to today’s vehicles with combustion engines.”
Today’s production standard eVito and eSprinter vans from Mercedes-Benz with electric drives have long since become powerful, practical vehicles with ranges of up to 184 kilometres in the case of the eVito. Their battery technology, as well as the components for the drive system, power control and charge management, benefit from the major advances in electric vehicle development in recent years. They have also fully established themselves in the market – as recently as the end of August 2020, for example, Amazon ordered more than 1,800 eSprinter and eVito battery-powered delivery vans for use in European markets.
Source: Mercedes-Benz Classic