Although growth does not always correspond with the set objectives, the number of electric cars on the roads is increasing. And a used-car market for these vehicles is starting to develop. The problem with this is: How can the vehicle be checked before buying? It is relatively simple with regard to suspension, brakes and tires. But what about the battery, which accounts for a significant part of an electric vehicle’s value? Is it still at its original performance level? How severely has it been affected by the wear of charging and draining? A time-intensive measurement would today be necessary to test it reliably, which is too complex for a quick used car check. A new rapid procedure, jointly developed by DEKRA and the Research Institute of Automotive Engineering and Vehicle Engines Stuttgart (FKFS), could soon provide a solution.
After years of research, the project can now go into the pilot phase next year. Both partners are currently presenting it at the EVS30 – Electric Vehicle Symposium – trade fair (October 9-11, 2017) in Stuttgart. The DEKRA and FKFS stands can both be found in hall 1.
“With our diagnostic procedure, we can determine the battery’s condition during a short test drive when it is under load,” states Andreas Richter of the DEKRA Electromobility Competence Center. This measures the current and voltage and evaluates them in relation to the reference values of a new vehicle of the same type. “The key statistic here is the battery’s internal resistance. The range and the energy, which is necessary to recharge an empty battery, are both dependent on this,” says Richter. “Therefore, the new procedure gives us an assessment of the battery’s condition.”
Although the result is not quite as precise as a detailed analysis, it is far less costly. For an extensive test, the battery is first completely drained and then recharged. The measured values identified will then be ranked and evaluated in comparison with a new battery. Overall, it requires a lot of time and energy, whereas the rapid process developed by DEKRA and FKFS provides a classification within minutes.
“When evaluating a used electric vehicle in particular, the assessment of the battery plays a very significant role, because it accounts for a large part of the vehicle’s overall price,” stated Michael Tziatzios, head of used car management at DEKRA Automobil GmbH. “However, for a used car analysis, a detailed analysis taking several hours is not practicable – ultimately, the cost for this type of expert report must still be in proportion. For this reason, we are very excited to put the new process into practice.”
The pilot phase of the project will begin at selected DEKRA branches in 2018. “We are currently busy preparing the process to be put into practice,” says Andreas Richter. The medium-term goal is to use the test procedure for used car evaluations for electric vehicles across all 75 DEKRA branches in Germany.