First-generation e-bikers have already made the bitter realisation: Over the years, the performance of the battery diminishes - and you have to look for a replacement. "Our experience is that the batteries last five, sometimes up to seven years," says bike dealer Thomas Huber from Radl-Huber in Munich. "We've been selling e-bikes for over ten years. Replacing batteries works without any problems. In our case, this applies to motors from Panasonic, Bosch or Brose. But of course there are also systems on the market where nobody is responsible for replacement batteries. You should stay away from those."
Arne Sudhoff from Derby Cycle promises: "We have our batteries in the programme for at least seven to ten years. With normal use, the service life is around 1,100 charging cycles, which is around six years." Jörg Lange from premium manufacturer Riese & Müller says: "We guarantee that the battery will still have a capacity of 60 per cent after two years or 500 full charging cycles - whichever comes first.
60 per cent capacity."
The battery is a wearing part
Why do lithium-ion batteries lose their performance over time and have to be regarded as wearing parts? The high-tech storage system is made up of around 50 cylindrical battery cells that are connected in parallel and in series. The battery cells are moulded into a carrier structure and enclosed in a plastic outer shell. Over time, chemical decomposition processes take place in the cells. Depending on the care and usage behaviour of the battery, these processes vary in severity. "Battery ageing is made up of the calendar service life and the cycle life," explains Dr Jochen Mähliß from the Batteryuniversity in Karlstein.
Storage alone causes the battery to gradually lose some of its capacity." Temperature also plays a role. The battery manufacturer BMZ Group assumes that an average temperature increase of ten degrees per year doubles the decomposition and dissolution rate of the cell chemistry, which leads to a halving of the service life. The cycle life depends on how the battery is used. Charging states, charging and discharging currents and the operating temperature have important influences.
Safety first
- Only use batteries (and chargers) that have been officially
officially approved by the vehicle manufacturer. Branded batteries must pass tests at accredited test laboratories for approval. - If a battery falls on the floor or receives a mechanical shock, the housing should be checked immediately. Batteries with visible damage (cracks, penetrated bodies, traces of smoke) should no longer be used or charged. Keep an eye on it and take it to the dealer immediately.
- Do not drill into a battery and do not attempt to open or dismantle it - even if you no longer need it.
If the capacity of the battery decreases, this has a direct effect on the range. For example, if your bike has a range of 80 kilometres when new, you will only reach 48 kilometres with a remaining capacity of 60 percent, 40 kilometres with 50 percent and so on. You have to decide for yourself at what remaining range you want to replace the battery.
Caution is advised if the battery has been damaged in a fall or accident. Batteries with visible damage should no longer be charged or used, but should be taken to the dealer immediately.
Free recycling
Your dealer should also be your first point of contact for a battery replacement. A good specialist shop will have a suitable diagnostic device and can check the battery condition. If you decide in favour of a new battery, the dealer is obliged to take back and dispose of the old battery free of charge. In Germany, recycling is usually organised by the Stiftung Gemeinsames Rücknahmesystem Batterien (GRS). More than 50 manufacturers finance the system as part of an industry solution. More than 2,300 bicycle dealers collect used batteries in large yellow containers. They are collected by the foundation and many recyclable materials are recycled in an environmentally friendly way.
Unfortunately, the battery is the most expensive spare part on an e-bike. Depending on the motor type, a new battery can cost up to over 800 euros. So it makes sense to search the internet for cheaper alternatives. Some common battery models are actually offered there at bargain prices. There are also companies offering tuning or replacement of individual cells or cell blocks.
What do we make of this? Every lithium-ion battery requires an intelligent, electronic battery management system that prevents the battery from leaving its safe operating range. It protects against high temperatures, overloading and deep discharge. It also determines the battery capacity, the current state of charge, the remaining operating time and stores life cycle data, among other things. The use of cheap and unsuitable batteries or the replacement of individual parts can be dangerous.
A lithium-ion battery for pedelecs is a class 9 dangerous good and special rules apply to its transport; special safety tests and a certificate are required for each battery type. So: Beware of no-name products. You should only use batteries and chargers that have been officially approved by the vehicle manufacturer.
The full article was published in MYBIKE issue 3/2018. You can download the issue in the MYBIKE app (iTunes and Google Play) or in the DK-Shop order.
