Technical articles on lithium-ion battery technology sometimes give different recommendations for battery care. One reason for this is that there are different types of lithium batteries. E-bikes and pedelecs today almost exclusively use lithium-ion batteries with NMC chemistry.
Mechanical care
Although the battery is a component that essentially consists of electrics and electronics, there are also physical care instructions to be observed. These can be found in the Operating instructions of the respective Stromer or as Tip from Stromer here.
One problem in particular should be emphasized here. The electrical-mechanical connection of the charger, the charging socket, the battery and the connection to the Stromer electrics in the battery compartment is realized by means of a magnetic plug connection from Rosenberger. This is often the cause of problems with the Stromer. It must be free of dirt and corrosion in order to function properly.

Treatment in regular driving operation
- The battery can be fully recharged after every ride.
- Carry out as many partial charges as possible. The so-called flat (discharge) charging stroke increases the service life of the battery and you are always ready for the next ride. The battery does not have to be discharged every time. There is no memory effect.
- Do not run the battery completely empty and recharge it after a short period of use.
- Avoid charging below 0 °C and above 40 °C battery temperature and in hermetically sealed rooms. Stromer interrupts the charging process outside this temperature window.
- If the temperature suddenly changes from cold to warm, condensation can form in the battery compartment and cause problems in the Rosenberger connection in the battery compartment below.
- If the battery is very cold, allow it to warm up at room temperature before charging.
- Always place the charger on a safe and stable surface.
- Do not charge the battery if the housing of the battery or charger is cracked or broken in any way.
- If possible, do not drive a very cold battery, but warm it up first as the cell chemistry is unnecessarily stressed and the ageing process is accelerated. There is also a risk of condensation forming in the battery compartment. If you have to set off with a cold battery, ride with moderate assistance until the battery has warmed up a little through riding.
- Do not store the battery in the bike in very cold temperatures, but at room temperature. Only use the battery in the Stromer for riding.
Treatment / Storage
Treatment:
- Opening the battery is prohibited
- The battery must be kept away from frost and heat, fire, sunlight, water and other liquids.
- Do not leave the Stromer in the sun for long periods in summer.
- Use a damp cloth to clean the battery, never use water or a high-pressure cleaner.
- Do not store with metal objects that can cause short circuits
Storage during longer periods of non-use:
- Store the battery inside or outside the bike at 10 - 15 °C. The Stromer must be switched off when stored in the bike!
- For storage, use frost-free and dry places such as cellar rooms, the garage or a well-insulated shed.
- Store the battery with a battery level of 40% to 60%.
- Check the charge status at regular intervals. If an NMC battery is stored correctly, it loses approx. 1% of its charge capacity (SoC) per week.
- Use the CR246 charger, which allows floating charging.
> See also 'Theory & terminology compendium for Li-ion batteries'
ST7 - BQ1440
The battery goes into a gentle sleep mode depending on the charge status and rest time. It starts after:
- 7 days if charge level SoC <10% or
- 90 days if charge level SoC < 80%
The sleep mode can only be ended by connecting the charger.