Lithium-ion batteries have a limited lifespan, which is not a new realisation, at least not since the advent of the smartphone. But by the time a new mobile phone battery is due, the mobile phone contract usually already allows the upgrade to a new model. This saves the customer the investment. The service life of lithium-ion batteries in e-mountain bikes is also limited, but here you have to dig deep into your pockets for a replacement: 600 to 800 euros are due when the worn-out energy storage unit has to be replaced with a fresh one.
How long does an e-bike battery last?
When an e-bike battery needs to be replaced essentially depends on two factors: "Battery ageing is made up of the calendar service life and the cycle life. The battery gradually loses capacity through storage alone," explains Dr Jochen Mähliß, expert for energy storage systems at Batteryuniversity GmbH in Karlstein.
Thomas Huber from Radl-Huber in Munich knows from experience that the batteries last around five, sometimes up to seven years. Arne Sudhoff from Derby Cycle calculates in charging cycles: "With normal use, the service life is around 1100 charging cycles. Experience has shown that this corresponds to a service life of around six years." At this stage, however, you won't be able to make any great leaps with your e-MTB for a long time. After 500 full charging cycles or around two years, you can only expect a capacity of around 60 per cent, according to the manufacturers. If you are deliberately sceptical and calculate with 30 kilometres Range per battery chargeWith 500 charging cycles, a battery has a service life of 15,000 kilometres - your e-mountainbike has to be able to cope with this without wear, breakdowns or defects.
>> Read more about sustainability in biking in our special: How can cycling be even better for the environment? <<
Why does the battery performance of E-MTBs decrease?
Over time, chemical decomposition processes take place in the battery cells. The actual problem lies in the structure of the lithium-ion battery. To put it simply: in a rechargeable battery, lithium ions move back and forth between the anode and cathode, i.e. the positive and negative poles. Over time, the electrodes oxidise and lose their ability to store the lithium ions required for the flow of electricity. Cell oxidation is influenced by various factors - for example, the ambient temperature and the state of charge.
This is also good news: the half-life of a lithium-ion battery can be influenced! Depending on the care of the battery and usage behaviour, the loss of capacity varies. Keyword: outside temperature. Batteries need to be stored in a cool and dry place. At temperatures above 30 degrees, the expiry date of the energy source runs out in fast motion. Batteries don't like frosty conditions either: if it's below freezing in the cellar in winter, you should find a safe, well-tempered place for the battery in your home. However, e-MTB owners can ensure that the service life of the e-bike battery does not expire too quickly, not only during storage but also during use: the battery management system ensures that the safety-critical range is not reached. But "cyclists should still try not to discharge their battery completely. And if you don't need the maximum range, it also makes sense not to charge the battery completely," recommends Dr Jochen Mähliß. If you make sure that the battery is not discharged below 10 per cent residual capacity and not charged above 90 per cent, you can significantly increase its service life, Mähliß even speaks of "doubling" it.
Specialised retailers offer battery diagnostics
Caution is also advised if the battery has been damaged due to a fall or accident. Batteries with visible damage should be taken immediately to a specialised shop that can check their functionality.
If the capacity of the battery drops, this has a direct effect on the Reach height out. For example, if you can manage 1500 metres in altitude with your bike when it is new, at 60 percent you can only manage 900 metres in altitude. If you want to know exactly, you need to contact your dealer. A good specialist shop will have a diagnostic device that can be used to check the battery status. You have to decide for yourself at what residual capacity you want to replace the battery.
It goes without saying that lithium-ion batteries should not be thrown away. The retailer is obliged to take back the old battery free of charge and return it to the recycling chain. In Germany, recycling is usually organised by the Stiftung Gemeinsames Rücknahmesystem Batterien (GRS). More than 100 manufacturers and importers finance this system as part of an industry solution. More than 2500 bicycle dealers collect the old batteries, which are then collected by GRS. Although there is still no technology for the almost complete recycling of all components, especially lithium, valuable materials such as cobalt, nickel and copper can be recovered from the batteries using the recycling processes already in place.
Can I use no-name batteries for my E-MTB?
As the battery is the most expensive spare part on an e-mountainbike, it makes sense to look for cheap equivalents on the internet. In fact, some battery models are offered there at bargain prices. There are also companies offering to replace individual cells or cell blocks. A good idea? A clear "No!" comes from the bike and motor manufacturers. The reason: every lithium-ion battery requires an intelligent electronic battery management system that prevents the battery from leaving its safe operating range. It protects against overloading due to overheating and deep discharge. It also determines the battery capacity, the current state of charge, the remaining operating time and stores life cycle data. The use of cheap and unsuitable batteries can therefore end up being particularly expensive. It is therefore much more sensible - and cheaper - to extend the half-life of the battery through proper handling.
9 answers about the e-bike battery life
Correct handling of the battery pays off: Greater safety, greater range, longer service life. You can find all the answers to FAQs about e-bike batteries here:
1 - Can I clean with the steam jet?
Steam cleaners are also taboo on classic MTBs - only Special cleaning equipment have a less potent jet and can be used with caution. On a pedelec, penetrating moisture can lead to the death of the electronics, motor or battery. It is therefore better to clean with a sponge and brush. Remove the battery and console beforehand, carefully clean them separately and cover the contacts on the e-bike for cleaning.
2 - Can I partially charge my battery?
Yes, partial charges are easily possible with lithium-ion batteries and are considered more gentle on the battery than frequent complete discharges.
3 - Can I ride my e-bike in winter?
At temperatures below 10 °C, batteries lose performance. They should therefore be stored in a warm place, fitted with an insulator when travelling and taken into a warm place for longer stops. However, high-quality batteries are characterised by a lower temperature sensitivity; the temperature range of the system is listed in the operating instructions.
4 - Where to put the battery during car transport?
If possible, the battery should be removed from the bike when it is transported on a roof or rear rack. Use neoprene covers to protect the contacts on the bike from the weather. Inside the car, the battery should not be exposed to direct sunlight. The best way to do this is to stow it in a battery transport bag or a corresponding bike rucksack.
5 - Is charging possible at any temperature?
No, batteries feel most comfortable between 10 °C and 40 °C. This applies to both charging and driving. Charging below 10 °C outside temperature is stressful for the cells and dramatically shortens the life expectancy of the battery. If it is too hot, there is a risk of overheating during charging. Intelligent battery control units have a protective circuit that prevents charging if it is too cold or too hot.
6 - Can I use someone else's charger?
To save weight, it is tempting to share the charger, especially on multi-day tours in a group. In principle, the combination of charger and battery must be approved by the manufacturer. For well-known manufacturers such as Bosch, Yamaha or Panasonic, this can easily be found in the operating instructions.
7 - Can I unscrew the battery?
Never open the battery housing; have broken housings - for example after a fall - replaced immediately by the manufacturer.
8 - Should I buy a used e-bike battery?
Buying a battery follows the rules for bike helmets and carbon components, for example. As previous damage cannot be ruled out beyond doubt by visual inspection, it is generally not advisable to buy second-hand.
9 - Can I dispose of old batteries in household waste?
NO - they are full of valuable raw materials. E-bike batteries are taken back by the manufacturer free of charge and recycled professionally.
"You can double the service life of a battery."
Interview with Dr Jochen Mähliß, head of the Batteryuniversity GmbH testing institute in Karlstein
E-MTB: Dr Mähliß, what can e-bikers do to maximise the service life of their e-bike battery?
Dr Jochen Mähliß: Cyclists should discharge their battery completely as rarely as possible. And if you don't need the maximum range, it makes sense not to fully charge the battery. When charging, the battery management system ensures that no safety-critical range is reached - i.e. the battery is neither overcharged nor overdischarged. However, if you regularly avoid the highest and lowest voltage ranges, the battery will manage significantly more cycles.
What does that mean in concrete terms?
If you want to protect your battery, you should not discharge it below 10 per cent or charge it above 90 per cent. This can double the service life of a battery. Incidentally, this applies to all lithium-ion batteries. Fast chargers are also problematic. The higher the charging current, the more the battery heats up and the more damaging this is for the cells.
Can you influence battery life by the way you drive?
Yes, a battery will last longer if you don't use it under full load too often. On the other hand, a leisurely riding style with a medium level of assistance protects the battery in the long term.
What should I bear in mind when storing the battery?
A battery likes it cool and dry. Temperatures above 30 degrees should be avoided. The battery should therefore not be left in the car in the sun or behind the window pane in the garage. Even if the bike is parked under a corrugated iron roof or in a wooden hut, it can get too warm for the battery. In this case, it is better to take it indoors.
And what about in winter?
The battery pack also does not tolerate storage at sub-zero temperatures well. Although this does not damage the cells, it does damage the plastic housing. It becomes brittle over time.
>> At the end of a strenuous season, after winter rides in salt and snow or simply in between: Your e-bike needs regular maintenance. We show you what you can do yourself for the 5 main areas of your e-mountainbike - without high workshop costs. DIY e-bike maintenance: wellness programme for the E-MTB
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