August 30, 2026, 2:32 pm | Read time: 5 minutes
In nearly every household, you’ll find battery-powered lawn mowers, leaf blowers, or vacuum cleaners. However, many users of such devices charge, store, and maintain their batteries incorrectly. As a result, performance declines faster than necessary, making the purchase of expensive replacement batteries necessary. myHOMEBOOK asked TÜV SÜD about the most common mistakes and how to extend battery life.
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Chemical Processes Cause Batteries to Age
Lithium-ion batteries are now found in almost all garden and household devices. They age due to chemical processes within the cells, as explained by TÜV SÜD. Over time, the usable capacity decreases. At the same time, the internal resistance, or the electrical resistance inside the battery, increases. This results in shorter device operation times. Additionally, performance may partially decrease under high load.
TÜV SÜD distinguishes between two types of aging in battery tests: cyclic and calendar aging. Cyclic aging occurs through charging and discharging. Calendar aging, on the other hand, occurs independently of use, meaning a battery ages even on the shelf.
Four factors particularly strongly influence lifespan:
- the number and type of charge cycles,
- the charging and discharging conditions,
- the temperature, and
- the quality of the cells, electronics, and battery management.
The storage location and the frequency and type of use also play a role.
Temperature has a particularly strong effect. High temperatures accelerate aging, while extreme cold temporarily reduces available performance. Frequent temperature changes and moisture additionally stress the battery’s electronics.
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These Mistakes Happen with Battery-Powered Garden Tools
Lawn mowers, hedge trimmers, and leaf blowers demand more from their batteries than small household helpers. They require significantly higher power for short periods, explains TÜV SÜD. This is where mistakes occur:
- completely discharging the battery
- using incorrect or unsuitable chargers instead of original accessories
- storing in extreme heat or cold
- continuing to use damaged batteries
- dirty or wet contacts
Especially with battery-powered garden tools, the battery can overheat. Therefore, it’s better to let the battery cool down before charging, advises TÜV SÜD. Modern batteries do have protection mechanisms against overheating, but the manufacturer’s specified charging conditions remain important.
The time of day and weather conditions also affect battery life. On hot summer days, operational heat is compounded by ambient heat. This increases thermal stress and accelerates aging. If the battery becomes unusually hot, a cooling break is recommended.
Moisture, dirt, and dust are also risk factors. Moisture promotes corrosion and electrical problems, while dirt and dust impair contacts and cooling. Therefore, the battery itself, all contacts, and the charger should be regularly cleaned, kept clean, and dry. A visual inspection for cracks, deformations, or swelling is also advisable. To further protect the battery, garden tools should always be stored without the battery.
Also interesting: Always store garden tools without the battery
Mistakes with Battery Devices in the Household
With vacuum cleaners, window cleaners, and handheld vacuums, other typical mistakes are evident. TÜV SÜD primarily cites
- permanently high charge levels,
- repeated deep discharges,
- high temperatures, and
- unsuitable chargers.
A classic issue is the permanent charging station: While modern devices have a battery management system that prevents classic overcharging, a permanent full charge can still accelerate the aging of a lithium-ion battery, emphasizes TÜV SÜD. Unless otherwise specified in the operating instructions, batteries should not be left in the charging station unnecessarily.
Device maintenance also indirectly affects the battery. Clogged filters or brushes force the motor to work harder, increasing the battery’s load. A clean device thus also preserves the energy storage.
According to TÜV SÜD, the noticeable performance loss of battery vacuums after just a few years is due to a combination of many charge cycles, frequent deep discharges, permanent full charges, high temperatures, and high power demands. Additionally, the lifespan strongly depends on the quality and design of the respective battery.
According to TÜV SÜD, storage locations with significant temperature fluctuations, such as kitchens, basements, or storage rooms, are also critical, especially when combined with high humidity or condensation. A dry place with stable, moderate temperatures is much better suited for storing battery-powered household devices.
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How to Charge and Store Batteries Correctly
For storing battery-powered garden tools, TÜV SÜD recommends a dry place at about 50 to 77 degrees Fahrenheit. In winter, avoid frost and moisture. The specific manufacturer’s instructions for each device should be closely followed.
For the charge state during longer storage periods, TÜV SÜD suggests a range of about 20 to 80 percent for lithium-ion batteries. Neither an empty nor a permanently fully charged battery is suitable for long breaks.
A battery left unused for months is generally unproblematic, according to TÜV SÜD, as calendar aging occurs regardless. It becomes critical only under unfavorable storage conditions or if the battery remains completely discharged for a long time. For idle periods, a dry, cool, and frost-free storage with a medium charge level is recommended.
A safety note concerns hot summer days: Very high temperatures can develop in a parked car. This not only accelerates aging, but also increases the safety risk with damaged or faulty lithium-ion batteries, according to TÜV SÜD. Therefore, battery-powered devices should not be left in a hot car for extended periods.
The Most Important Rules for a Long Battery Life at a Glance:
- Use the original charger, avoid cheap alternatives
- Let the battery cool down after heavy use before charging
- Avoid complete discharge and permanent full charge
- Store in a dry, clean place at moderate temperatures
- For longer storage without activity, choose a medium charge level
- Regularly check for cracks, deformations, or swelling.
By following these points, you can significantly extend the lifespan of your battery devices and save on expensive replacement parts.