ECN publication
Energiegebruik elektrische 'VW Caravelle': verwerking en analyse van meetgegevens uit de praktijkproef
Published by: Publication date:
ECN Policy Studies 1-10-1999
ECN report number: Document type:
ECN-C--99-070 ECN publication
Number of pages: Full text:
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The demonstration project with electric Volkswagen Caravelles started atthe end of 1995 with 3 vehicles. During the project the number of vehicles increased up to 12. The Volkswagen Caravelle is a small passenger bus with 7 seats. The objective of the project is to gain experience with electric vehicles in daily use. The aim of the various measurements which were carried out is to get an insight into the behaviour of the electric vehicles used. The prime area of the investigation is related to the energy use. The first measurements on the road showed a much higher energy consumption compared to what was expected on the basis of rolling road measurements. During the demonstration project it quickly became obvious that the initially high energy consumption showed a gradual reduction in time. To drive efficiently with the electric VW Caravelle is clearly a process of familiarisation. To explain the differences in energy consumption of the different participants an extensive search for possible causes was carried out. lt is remarkable that there seems to be no direct relationship between the average speed of a trip and the energy used. The duration of a trip can have a significant impact on the energy use of a vehicle. Most vehicles followed the trend that the longer the trip the lower the energy use per kilometre driven. The possibility to recuperate braking energy is an important characteristic of electric vehicles. For an electric vehicle it presents a possibility to extend its range on one battery charge. Recuperation percentages of 5.9 to 15.9% were measured during the demonstration project. During the period over which measurements of the energy consumption from the grid were ta- ken, the actual primary energy use of the electric VW Caravelle was higher than for a conventional diesel version. The most important reason for this finding is the fact that the total losses in the charging process of the traction batteries are so high (55%). Even if a period is taken in which the electric VW Caravelle was at its most frugal, the primary energy use was still slightly above that of the diesel version. The charging process of the traction battery as specified by the battery manufacturer is mainly responsible for the substantial losses. Further investigation will be necessary to reduce the losses in the charging process of the battery. Fast charging is already a possibility to reduce the charging losses. 7 refs.

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