E-bikes have often been optimized more with regard to costs and less with regard to best possible power delivery. Compared to other electrically powered vehicles, pedelecs therefore often perform poorly in terms of efficiency and range. Researchers at Karlsruhe Institute of Technology (KIT) now want to improve e-bikes and have set up a special test bench for it.

Martin Doppelbauer from the Institute of Electrical Engineering (ETI) at KIT notes that most motors that are now installed in e-bikes were originally developed as drives for other small electrical devices, for example for power steering in cars. While the motors are bad per se, they have not really been optimized for providing the best performance.

While an average electric car currently has an efficiency of 90%, in conventional pedelecs, it’s only 70 percent, said Doppelbauer. Future motors need to be particularly more compact, and therefore smaller and lighter with a greater range.

To achieve this, researchers at ETI are using development methods and findings from larger drives for battery electric vehicles that are already highly developed and applying them to small pedelec motors.

There is also room for improvement in components such as gears, cooling, power electronics and not least the battery.

So far most manufacturers don’t offer a quick charge system. City bikes need to be chargeable in half an hour while shopping, then batteries can be made smaller, lighter and therefore more practical.

—Martin Doppelbauer

ETI is now developing one together with a Heidelberg e-bike manufacturer.

To put the new developments through their paces, the ETI researchers have set up a new test bench which is commonly used in the automotive industry. The bikes will go through different cycles at all speeds, and ascents and descents can also be simulated, the way it is also done with large motors.