Tips for the safe use of powerbanks

Powerbanks are mobile charging stations for electrical devices such as smartphones, tablets or cameras. But be careful: as with all lithium-ion batteries, there is a certain risk of fire and explosion. TUV Verband gives advice on the purchase and safe use of powerbanks.

"Powerbanks are mobile charging stations that are powered by a lithium-ion or lithium-polymer battery," explains Dr Hermann Dinkler, fire and explosion protection expert at TUV-Verband. "But the small energy storage devices can become dangerous if the material is damaged or used improperly, and in the worst case they can start a fire." In order to still be on the safe side, the TUV Verband has put together some tips on what consumers should look out for when buying and using powerbanks.

When buying, pay attention to capacity and charging connections

Powerbanks store energy in the form of electricity and deliver it to small devices when needed. Consumers should pay attention to the technical specifications such as capacity and charging ports when buying. The capacity is given in milliampere hours (mAh):  The more mAh a powerbank has, the greater its charging capacity. The average battery capacity of powerbanks is around 20,000 mAh. Basically, the more battery capacity a powerbank has, the heavier it is.

Consumers should also make sure that the output voltage (V) of the powerbank matches the devices used. Otherwise, the devices could be damaged. 

Dinkler: "Powerbanks often have different connections that charge small devices with different amperages. Therefore, consumers should check which port charges which device." 

Modern powerbanks have an intelligent charging mode that can be used to optimally adjust the charging process of different devices. In addition, some powerbanks have a charging surface for inductive charging of the end device. However, wireless power transfer is less efficient. The "pass-through charging" function is also practical. This makes it possible to charge one or more devices on the powerbank while it is charging itself.

Taking it with you on the plane: Pay attention to the capacity of the powerbank.

The following applies to air travel: for safety reasons, holidaymakers are only allowed to carry powerbanks in their hand luggage. A maximum of two powerbanks with a maximum capacity of 100 watt hours or 27,000 mAh each are allowed per person. However, these regulations may vary from airline to airline. Holidaymakers should therefore find out about the relevant regulations in advance on the website of the respective airline. Passengers are also prohibited from charging devices on the plane with a powerbank.

If you are looking for a powerbank for use during outdoor activities or at the beach, you should make sure that it is dustproof and waterproof. Appropriate powerbanks are marked with special protection type certifications. IP67-certified powerbanks, for example, are dustproof and largely waterproof. They are protected against temporary submersion in water up to a maximum depth of one metre for a maximum of 30 minutes.

For longer outdoor trips, so-called solar power banks can be worthwhile. 
These can be charged like conventional power banks at the socket, but have a small integrated solar module with which the power bank can be recharged with sustainable solar power while on the move. However, the charging process takes longer than at the socket. For a completely self-sufficient power supply, a solar charger with USB connection is more suitable for charging conventional powerbanks.

Caution when using powerbanks

As with all lithium-ion batteries, there is a certain risk of fire and explosion with powerbanks. Incorrect handling or improper use can, in the worst case, lead to accidents with personal injury. "If a powerbank is damaged or falls down, short circuits can occur inside the battery cell. In the worst case, the resulting heat can lead to a fire," says Dinkler. "Damaged powerbanks can be recognised by bloated or deformed housings, melting spots or discoloured metal parts. In such cases, consumers should immediately dispose of the device properly, for example at public collection points or recycling centres."

Whether on the beach or in a ski resort: Powerbanks must not be exposed to extreme temperatures, neither during operation nor during storage. Therefore, they should be protected from direct sunlight. "If a lithium-ion battery is overheated, an electrochemical reaction occurs in which the battery can heat up to 1,000 degrees in a very short time. The battery can inflate and even explode, depending on the type of construction and chemicals used," explains Dinkler. For this reason, powerbanks should not be stored in a closed car, for example, or even on the dashboard in direct sunlight. 

Carrying powerbanks with a connected mobile phone in your pocket can also be dangerous. "The heat generated when charging the mobile phone with the powerbank in combination with high summer temperatures can lead to burns," says fire safety expert Dinkler. In addition, powerbanks should not be left connected to the charger for too long to avoid overheating. "If the battery starts to burn, toxic fumes are produced. Consumers should immediately seek safety and call the fire brigade in this case," says Dinkler. Contact with the harmful fumes should be avoided, he adds. "Attempts to extinguish with water are also not advisable, as lithium reacts with water," says Dinkler. Consumers should also keep checking the temperature of the powerbank during the charging process. If it gets so hot that it can no longer be held in the hand without problems, the charging process should be interrupted.

The hazard potential of powerbanks can be reduced by proper storage. If powerbanks are not used for a longer period of time, consumers should charge them every now and then to avoid deep discharge. This can significantly extend the life of the batteries.

Pay attention to test marks when buying

The requirements for transporting lithium batteries are laid down in UN standard 38.3. For safety aspects, the international standard IEC 62133-2 applies. It specifies requirements for the safe operation of gas-tight accumulators and batteries for portable devices. To ensure that consumers can be sure that the legal requirements have been met by the manufacturer, they should look for the CE mark when buying powerbanks. The GS mark for tested safety and the TUV test marks offer better orientation. Powerbanks with these seals have passed an independent test based on a standard. "Consumers should view very high charging capacities at a low price with caution," says Dinkler. "So-called no-name products can also be faulty. If no manufacturer is indicated, consumers should rather refrain from buying the powerbank."