Safety When Handling and Charging Batteries

Useful Tips and Important Information for E-bikes and Pedelecs

The trend toward bikes with electric assist continues unabated: According to figures from the German bicycle industry association ZIV, around two million bicycles with electric drives were delivered in Germany in 2021 alone. This means that almost every second bicycle sold had a motor! We talked to an expert from the branch information service pressedienst-fahrrad (pd-f) about the topic of e-bikes and battery charging safety.

Tens of millions of bicycles with electric drives are now on our roads. And experience shows that it is a fundamentally safe technology. This also applies to the battery: If handled correctly, a modern lithium-ion battery does not pose any recognizably significant fire hazard.

To ensure that the battery lasts long and safely, users should nevertheless observe a number of guidelines, especially when charging. It is essential to follow the original operating instructions for your battery or charger! In addition, we provide you with useful tips and important information here in the interest of your safety. What this means in practice is explained by e-bike expert and specialist book author Gunnar Fehlau from pressedienst-fahrrad (pd-f).

Only Original and Intact

The highest commandment with handling rechargeable batteries: No experiments! That means, first, never connect the battery to anything other than an original charger; and second, never try your luck with damaged parts. “If I know that the battery has been dropped, I shouldn’t spend time wondering whether it might not have been damaged on the inside or not. If it has visible flaws, three times not,” explains Fehlau.

Your specialist dealer can help if your charger or battery is damaged or you suspect damage. For do-it-yourselfers, it’s simply: Hands off! “This also applies to your acquaintance, who has ‘done the same thing before'”, warns the expert.

The repair of rechargeable batteries and battery technology belongs in expert hands. Where your dealer can’t help himself, he will take care of shipping to the manufacturer – rechargeable batteries are considered hazardous goods and may not be shipped by private individuals.

Prevent Overheating

Even if the battery and charger perform noticeably less in very cold conditions: “The danger is at the other end of the thermometer,” says Fehlau. Overheating, he specifies, is the biggest problem when charging batteries, along with defective or incompatible devices.

Therefore, always protect the charger and batteries from heat! This can come from outside, for example, from strong sunlight or if the battery is to be charged next to a radiator. But the battery and the charger itself also get warm when charging.

To prevent heat buildup, never cover them when charging – especially not with flammable or combustible material such as carelessly discarded clothing. Ensure good ventilation!

Avoid Moisture

Ventilation is important for another reason as well. Like all electrically powered equipment, batteries and chargers are sensitive to moisture and humidity. “Out of the downpour straight to the charger is not a good idea for a battery,” the e-bike expert advises.

Wetness on the surface can be wiped off with a cloth. But especially with large temperature differences between inside and outside, condensation can also form inside the battery. Give the battery a rest in a dry, well-ventilated place before charging it!

Precipitating moisture also forms when batteries and possibly chargers are stored and charged in cold, poorly ventilated rooms. “The cold musty basement or the garage overnight are not suitable charging stations,” explains Fehlau. Especially since the necessary supervision of the charging process is usually not possible here either.

Only Charge Under Supervision

Only charge the battery under supervision! This does not mean that you have to stare at it continuously until it has finished charging. The decisive factor is to be able to quickly detect a problem at any time and to react in the case of an emergency. In principle, this is ensured when charging in your own home. But not if you spontaneously remember that you have to make a quick trip to the supermarket.

Children or people with limited abilities to react properly in the event of an emergency are not capable of monitoring the charging process in this case. Do not transfer the task of supervision to them! If you really need to get out of the house, it’s actually quite simple: You can interrupt the charging process at any time and pull the plug. But maybe you’ll take the bike anyway …

We have deliberately given space to our tips on charging batteries as an important topic here. The renowned bicycle safety expert Dipl.-Ing. Dirk Zedler puts it succinctly though: “Treat your brand battery gently, charge it during the day at room temperature under supervision and as described in the operating instructions. Then there is no danger”. In addition, please also note our information sheet on safety when charging rechargeable batteries. We wish you safe and enjoyable rides at all times!