Answers by Dirk Zedler, bicycle expert
Energy storage devices of renowned manufacturers have been subject to numerous tests; they typically do not pose any problems as long as the suitable charger is used. Using the charger of another manufacturer only because the plug fits can result in a short-circuit and in the battery catching fire. Best charging results are achieved at a temperature of 20° Celsius. The connections must be dry. When you transport your bike on a carrier outside your car, remove the battery and protect the connections (e.g. with a plastic bag) against moisture and dirt.
What do I do with a defective rechargeable battery?
Due to wear, the battery capacity reduces gradually. That means, however, not that a battery has to be disposed of right away. That means only that the range decreases. Real defects, such as cracks in the housing or obvious deformations as well as severely bent connections, represent however a risk. The battery must not be used any longer. Such kind of defects can result in short-circuits, the battery can ignite spontaneously. A defective battery must be returned to the dealer; they will either check inhouse or send it in to the manufacturer. In case of doubt, it’s always best to replace the battery. Dealers are obliged to take back the used batteries and to recycle them.
What about fires caused reportedly by rechargeable batteries?
These are exceptions. In such a case the battery handling was normally not correct. Frequent causes for defects are self-built and modified series batteries. For this reason I strongly recommend that you do not drill, open or fix anything to batteries.
And in case they will catch fire nevertheless?
Battery fires are uncontrolled, chemical reactions of metallic compounds. Usual fire extinguishers are not suitable in such a case. What you need is a fire extinguisher at fire protection class D. A practical solution is a drum of sand in which the battery can be thrown. By adding further sand and closing the cover the fire will extinguish. As these fumes are very toxic, the drum has to be brought outside as quickly as possible. A drum should therefore stand in every bicycle workshop.
Photo: Daniel Geiger