In general, the battery of an electric bicycle has a service life of several years if used according to the manufacturer's instructions. However, in the event that the battery presents any problems, experts advise against trying to repair it on their own. Not only can warranty rights be lost, but it also poses a safety risk and even risks causing a fire. On some models, wear and tear and condition can be checked on the battery itself. In addition there are bicycle repair shops that have a special battery diagnostic device. The result of the so-called state of health (in English, State of Health, SOH) provides information about the remaining capacity and battery performance. In most cases, the reason why the battery of the electric bicycle suffers a defect is due to its incorrect storage during long breaks, for example in the winter months. The website “efahrer.com” advises maintaining a charge level of between 30 and 70 percent if it is not used for a long period of time. It is also ideal to store the bike or battery in a dry place at temperatures between 0 and 20 degrees. If the battery offers less and less autonomy with each charge, it may be due to several reasons: the load, the weight of the cyclist, the driving mode, the tire pressure or deficiencies in the overall maintenance of the bicycle. The cause may also be a failure in the bearing of the electric motor. However, according to experts, this is rare. Before buying a new battery, it is important to check if the defective battery is still under warranty. Since original batteries are usually relatively expensive, you can consider buying a device from another manufacturer. However, “efahrer.com” advises to “play it safe” and equip the bike with an original battery. There is often no way to verify whether other brands' products meet safety and quality requirements. dpa