Battery: It’s the Care that Counts

Author: Matthias Gaul

Nov 15, 2023 Safety on the road / Mobility

If you love your e-bike, you should not only take care of the bike itself, but also of the battery. A DEKRA bicycle expert explains what is particularly important.

The Pedelec trend continues unabated. According to a bicycle study published in June 2023 by management consultant Ernst & Young, e-bikes accounted for 62 percent of the total sales volume of bicycles sold across Europe in 2022. This share is set to rise to over 80 percent by 2028. Germany and the Netherlands are already at this level today. Of course, proper care of the battery plays a vital role in ensuring that the enjoyment of the respective vehicle lasts as long as possible. “Poor handling not only limits durability and range, but also poses a safety risk that should not be underestimated,” says Tilo Eilers, expert for bicycles, Pedelecs, S-Pedelecs, and e-bikes at DEKRA Automobil GmbH.
To avoid these dangers, the first thing you should do after purchase is to carefully read the operating manual, which contains many useful instructions for use. “If a battery has been damaged by improper charging or by a fall, for example, or if it has become too hot, this can result in a short circuit with a chain reaction,” the DEKRA expert warns. In other words, the battery may catch on fire or even explode and start to burn. And because a battery has a large number of cells, explosions can last for several minutes. In addition, fumes from burning lithium-ion batteries are highly toxic.
If possible, avoid dropping the battery, and load and transport it correctly
Let’s talk about falls: According to the standard, Pedelec batteries are designed to withstand three falls from a height of one meter onto a hard surface without being damaged. The battery is very likely to be damaged if it falls from a greater height or more than three times. It is advisable to have the battery checked by a specialist after the first fall, even if no external damage is visible. This is because the impact can cause contacts inside the cells to come loose and the battery to ignite during charging. If that happens, quick action is required. “Immediately take the bike away from flammable objects, step away, and call the fire department,” Tilo Eilers advises.
As far as charging is concerned, you should only use the original charger. Only charge the battery in a dry place, ideally at room temperature, and away from flammable objects. Partial charges to 50 to 85 percent extend the battery’s service life. Of course, you can also fully charge the battery immediately before a longer tour. The risk of overcharging is virtually eliminated with a certified branded product. Avoid deep discharging.
If you take your bike on vacation and transport it on the outside of the car, it is advisable to remove the battery and place it inside the vehicle to protect it from moisture and strong vibrations. “Water getting into the battery packs can lead to a short circuit or even corrosion in the long term, and the vibrations in turn can damage the cells and contacts,” says the DEKRA bicycle expert. For the summer, it is also important to ensure that the batteries are not exposed to the blazing sun, as temperatures above 60 degrees can damage the cells also. Many manufacturers now also recommend this in their bicycle manuals.
Only insert the tempered Pedelec battery right before heading out
Incidentally, Pedelec riders must also rethink how they handle their battery in winter. This is because, same as with electric cars, the performance of the bicycle battery is optimally utilized if it is charged at room temperature and only inserted shortly before you head out. If the Pedelec is parked in the cold for hours, it is better to store the battery in a warmer cellar during that time. Do not start charging the battery when it is cold, but only when it has warmed up to room temperature. In icy cold conditions, a thermal protection cover is also useful as it keeps the battery warm for longer and can therefore increase its range. For longer journeys on cold days, it can be useful to have a charger with you.
If the Pedelec is hibernating over the cold days, make sure that the charger is not left permanently connected. The best way to extend the battery’s service life is to store it at a temperature of 10 to 20 degrees Celsius with a charge level of 30 to 70 percent. Clean the battery according to the manufacturer’s instructions. In this case too, it is worth taking another look at the manual.