Pedelecs with a forceful and well-adjusted rear wheel or a centrally mounted motor are pure fun. They provide fast acceleration and easy climbing. If the battery falls short during a long climb, the cycle trip with the pedelec turns, however, from fun into hard work. Instead of lightheartedly climbing the hill, you now have to force an about 20 kilograms heavy bicycle up the hill. It therefore often happens that the first extended ride with the pedelec dampens the euphoria of many customers and renders them from content customers into grumblers in the bike shop.
What is absolutely thrilling about the electric motor is that the rider can rely upon the torque from the first rotation to the maximum speed. This is a major advantage over the speed-dependent torque curve of the combustion motor.
It is, however, also fact that the volumic energy, i.e. the available energy from the kilogram storage, of all currently available batteries represents only a fractional amount of motor fuels. To reach comparable ranges it would therefore be necessary to fit the pedelecs with huge and thus heavy batteries. This is the reason why the automotive engineering currently experiences a lightweight construction wave, including carbon as well. Cars must simply “make weight“ to be able to take an acceptable energy storage aboard. Nevertheless, cars are still miles away from a reasonable application. The very favourable initial ratio between vehicle weight and payload means, however, very good preconditions for the bicycle. In the case of the bicycle, electric mobility has already become reality.
Too short range
Of the praised 70 km (44 miles) of range not even half is reached by many riders in practice. Deceptions and the first accidents are due to the fact that the customers are not able to adequately handle the technology and that the bicycles still have a huge improvement potential.
Quickly discharging batteries are often due to the fact that the riders are too lazy to shift. Instead of pedalling in a flow and to reasonably apply the own forces, riders shift less than without drive, thus forcing the motor to work hard.
Instead of shifting down before stopping or in the case of gear hubs in stationary, setting off in front of traffic lights is made with a large gear ratio. The car engine would stall, setting off by bicycle would be very hard, whereas the motor of the pedelec accelerates, but empties the battery quite fast.
What is more in the case of bicycles, the laziness in terms of care and maintenance, shortens the range in addition. One bar less the accurate inflation pressure and a squeaking chain already reduce the range by a few important kilometres/miles. A foot-operated pump with pressure gauge and a bottle of chain oil are therefore reasonable accessories to be sold with the pedelec.
The chemical processes of a battery cannot be repeated at will. As a result the batteries wear down and gradually loose capacity. Depending on the manufacturer, batteries are designed for 500 to 1000 (complete) charge cycles, but even at this point the battery is not yet completely worn down, but still has residual capacity. Nevertheless, the moment comes where the battery is up for replacement, which actually hurts in consideration of the current prices of approx. 500 Euro and more.
Many pedelec riders fear the fast reduction of the charge cycles and therefore always deep discharge the battery, which is absolutely wrong in the case of lithium ion batteries. It is much better and recommendable for an always available maximum range to recharge after every ride. Counterproductive for the customer behaviour is the long discussed memory effect of former battery versions which is no longer a problem for current generations. For this reason, customers need to obtain competent information from their bicycle dealer and detailed instructions in form of a comprehensive user manual provided by the manufacturer to back away from the old doctrine.
Getting used to the riding behaviour
Cyclists who have been riding for years willl probably ride a pedelec like a bicycle. This is, however, not always like it should be. By far not every pedelec is driven and controlled in a way that it neatly follows the (pedalling) commands of the rider. Deceleration and a sudden reacceleration can be also dangerous. The drive continues to push although the rider has already stopped pedalling.
Every customer will have to get used to this kind of cycling, but a lot of drives have an intolerable and dangerous riding behaviour. It is also a false conclusion to assume that different bicycle manufacturers and models have the same drive system with identic riding characteristics. Huge differences arise from the choice of the sensor technology and the application, i.e. the manufacturer specific adjustment.
Analogous to the chip tuning in the case of automobiles to reach different performance levels, the software in the case of the pedelecs renders a gentle tail wind into a stormy acceleration.
The dealers would do well to do test rides with the pedelecs they intend to order.
In particular, in terms of electronics there is still plenty of room to grow. This applies to battery management, the science of controlling and operating every single cell of a battery during charging as well as during the ride. In future, the tuning of the motor must become more individual and easier at the same time. This is best done by programming them for every type of rider. Further electronic elements, such as navigation, power measurement etc. will find their way to the pedelec via integrated smartphone. And last but not least, the recuperation, i.e. the conversion of kinetic energy during braking into electricity instead of in heat should be intensified.
New ways, like the automatic gear shifting systems from NuVinci and TranzX presented on the show, will support the ider in future and make sure that he will take care of himself and the battery. May the arms race of the manufacturers begin.
Author: Dirk Zedler