Without powerful lithium-ion batteries, there would be no e-bikes - at least not in the way we appreciate them today. They are what make the riding performance and ranges that are possible with current pedelecs possible. However, they are also a wearing part, because batteries age. And regular charging and discharging wears down the chemical substance.
Depending on the manufacturer's definition, an e-bike battery is considered worn out if it still has 60 to 80 per cent of its capacity. Unlike other bicycle parts, such as brake pads, "worn" in this case does not mean "defective", "dangerous" or "must be replaced". If you can manage with the available, lower range, you may still be able to use the weakening e-bike battery for some time. In an ADAC battery test, batteries with approx. 1,500 charging cycles were brought to a residual capacity of 30 per cent and only then sent into retirement as "barely usable".
E-bike battery: ageing by doing nothing
But it's not just the charging cycles, but also the years that take their toll on e-bike batteries. Even if they are not used at all during this time. According to industry sources, common cell types produced before 2014 lose around 2 to 3 per cent of their capacity per year through storage alone, while the figure for newer cell types is only 0.5 to 1 per cent. The extent of the loss through use is of course very individual. Battery packs are usually designed for 500 to 700 charging cycles. Depending on usage behaviour, this figure can vary considerably both upwards and downwards. Sooner or later, however, even the most powerful battery loses a large part of its capacity and has to be replaced.
Fresh cell treatment for the e-bike battery? No such thing!
Once the decision has been made to look for a new energy storage system, there are a few points to consider before buying spare parts. The path is clearest for buyers of branded products from specialist retailers.
The first port of call is the dealer, who can check the battery condition in his workshop using the appropriate diagnostic tools. They can make a binding assessment of whether a replacement is unavoidable and suggest a suitable model. At this point at the latest, the customer wants to know what options are available. After all, the e-bike battery is by far the most expensive spare part on an e-bike. It ranges from around 200 euros for a small battery from a non-name manufacturer to the original Bosch Powerpack with 500 watt hours at a list price of around 800 euros. It's understandable that people want to save money. However, customers don't usually have too many options.
The idea of "refreshing" an ageing battery is practically always doomed to failure. Lithium-ion batteries - for all their advantages - are one of those battery types that cannot be given a new lease of life in any way. Once they are used up, that's it. Recalibration, which is often recommended, merely ensures that the current charge level is shown correctly on the display again. This does not change the basic available capacity.
Caution: No experiments with e-bike batteries
You should refrain from experimenting with e-bike batteries on your own. Bosch press spokeswoman Tamara Winograd also emphasises this: "Lithium-ion batteries are complex, finely tuned systems with a high energy content. End customers, dealers and bicycle manufacturers should never open the battery. There is a risk of a short circuit. Opening or modifying the batteries also voids any warranty claims."
Serious batteries, healthy solutions
Instead, she recommends the service process between customer, retailer and manufacturer. "To obtain information about the condition of the Bosch Power Packs, the consumer should visit a bicycle dealer. Using the Bosch diagnostic tool, they can read out the number of charging cycles and determine whether the battery is technically in order. Bosch power packs are also best obtained from the dealer. They can easily organise the supply of spare parts and retrofitting via the online shop of service partner Magura."
When it comes to the supply of spare parts, e-bike battery suppliers generally endeavour to find solutions that are as customer-friendly as possible. They have obviously recognised that this is good for the entire product category. BMZ in Karlstein, the European market leader for e-bike batteries, is also able to replace individual parts such as the housing, electronics or the core pack, i.e. the cell core, in its own batteries. According to BMZ, this is an effort that no other manufacturer in Europe takes on. If this is possible with their own e-bike battery, the customer will save more money than buying a new battery.
E-bike manufacturers are also endeavouring to guarantee the supply of spare parts for as long as possible. It is usually assumed in the bicycle industry that the life cycle of a bike ends after six to seven years. "Even if the period of six to seven years is exceeded, we still try to ensure the supply of batteries," says Arne Sudhoff, press spokesman at Derby Cycle, explaining the company's own requirements. With the introduction of its own Impulse drive system in 2012, the use of Panasonic motors was discontinued. Nevertheless, replacement batteries are still available for these bikes.
In the case of replacement batteries from third-party manufacturers, however, you should check carefully whether they are suitable for your own pedelec in view of the complexity of the systems - especially if they were not explicitly manufactured for the drive system. Due to the finely tuned interaction of the components, they cannot be interchanged at will. If you find a universal battery on the Internet that seems to fit your own system at first glance, you should be careful and find out exactly about the operating licence, warranty and compatibility. If you install such batteries on your bike without thinking, you risk damage to the motor, overcharging or even a battery fire.
Time to say goodbye...
Lithium-ion batteries have been state of the art on bikes since around 2009/2010. Anyone riding an older e-bike may still be using nickel-cadmium, nickel-metal hydride batteries or other older systems. It is now difficult to find replacement batteries for these bikes. What's more, they pollute the environment due to the substances they contain and provide less power. It is not for nothing that lithium-ion batteries have now replaced all other types of e-bike battery. At best, small specialised manufacturers, possibly even from the Far East, can still help in this situation. However, everyone must decide for themselves whether this investment is still worthwhile in view of the significantly better performance of modern e-bikes. Lithium-ion batteries definitely have a long-term perspective. They are likely to remain the gold standard in battery technology until at least 2030, despite the announcement of further innovations.
The moral of the story'...
So if you ride a pedelec with a lithium-ion battery from a specialist retailer and therefore a product from a major supplier in the industry, you will almost certainly still have the prospect of getting an equivalent replacement battery in the long term. The situation is different for customers who are travelling on an electric bike from a little-known manufacturer from the Far East. It can easily happen that no original replacement battery is available after a few years - and universal batteries from often dubious sources are then often the only way to keep the bike running. With all the risks mentioned...
6 tips for a long e-bike battery life
1. no extremes
It's like with humans: Moderation is the watchword. The states "completely full" and "completely empty" place a heavy load on the battery. If it is operated in the range of 20 to 80 % of its capacity, this extends its service life disproportionately. Studies by cell manufacturers show that the service life can be doubled in this way.
2. half things
This means that you should charge the battery occasionally and only partially. Partial charging cycles are added together. Whether you charge once from 0 to 100 % or twice from 30 to 80 % charge level: both result in one charging cycle. There is no memory effect with lithium-ion batteries.
3. calibration
You should still run the lithium-ion battery completely empty and recharge it about once a year. This allows the electronics to recalibrate. Imagine the battery as a barrel full of water with sand at the bottom. If the barrel is completely emptied and refilled, you will know how much water it can currently hold.
4. handling
Keep the battery contacts free of metal shavings and other dirt, as there are often various magnetic connections on pedelecs. You should also avoid grease on the contacts. There is a risk of malfunctions and short circuits.
5. hibernation
If you do not use the bike for a longer period of time, remove the battery from the bike and store it in a dry place at around 10 degrees with a charge level of 30 to 60 %. Check the charge level from time to time and recharge if necessary.
6. recycling
Discarded rechargeable batteries and batteries should not be disposed of with household waste. When the battery is finally discarded, take it to a specialist dealer who will dispose of it properly or pass it on for recycling.
The full article was published in E-BIKE issue 2/2017. You can download the issue in the MYBIKE app (iTunes and Google Play) or in the DK-Shop order.
