Between convenience and safety requirements: What really matters when it comes to mobile power banks

Smartphones, tablets and wearables have long been an integral part of our connected daily lives. As our reliance on mobile devices grows, so does the need for a reliable power supply when we’re on the move. Power banks have established themselves as indispensable companions. Yet the market is fragmented: there are significant differences between cheap no-name products and technically sophisticated branded solutions – particularly in terms of safety, performance and lifespan. The testing service provider TÜV SÜD offers guidance on what consumers should look out for when making a purchase.

Capacity and real-world performance: More than just mAh

A key selection criterion is capacity, specified in milliampere-hours (mAh). This determines how often a device can be charged. For everyday use, 5,000 to 10,000 mAh is sufficient in many cases. However, anyone wishing to power multiple devices or energy-intensive applications – such as tablets or laptops – should consider more powerful models.

The key factor, however, is the difference between nominal and usable capacity. Energy losses due to conversion processes, temperature conditions and charging electronics mean that the energy actually available is lower than the stated value. For a realistic assessment, therefore, not only the capacity but also the efficiency of the power bank is relevant.

Fast charging as standard: power and compatibility

With the increasing prevalence of fast-charging technologies such as USB Power Delivery or Qualcomm Quick Charge, output power is becoming a decisive factor. Modern devices only benefit from reduced charging times if the power bank and the device support the same standard.

For smartphones, 18 to 30 watts is often sufficient, whilst tablets or laptops may require power outputs of 45 to 65 watts. Choosing the right power bank therefore depends heavily on the individual usage scenario.

Ports and functionality: Focus on flexibility

In addition to power output, the variety of ports plays a central role. USB-A remains widely used, whilst USB-C is increasingly becoming the standard – not least due to higher charging power and bidirectional usage options.

Power banks with multiple outputs allow several devices to be charged simultaneously, which is particularly relevant in a professional or travel context. Additional features such as ‘pass-through charging’ – i.e. charging the power bank and the device simultaneously – offer convenience, but for safety reasons should only be used with high-quality devices.

Safety architecture: protection mechanisms are essential

Power banks are based on lithium-ion or lithium-polymer technology and pose significant risks if of poor quality. High-quality models feature built-in protection mechanisms against overcharging, deep discharge, short circuits and overheating.

Missing or inadequate protection circuits can, in extreme cases, lead to thermal incidents or even fires. External factors such as mechanical damage, moisture or extreme temperatures also have a significant impact on safety. A robust casing design and high-quality electronics are therefore essential.

Certification marks and transparency: navigating the market

Reliable labelling is an important indicator of quality and safety. Whilst the CE mark is mandatory, additional certification marks such as the GS seal (‘Tested Safety’) or the TÜV SÜD octagon provide evidence of independent testing.

Products without clear manufacturer details or with incomplete technical specifications should be viewed with scepticism – particularly in the case of very low-priced offers or anonymous online sales channels.

Mobility and usage context: weight, robustness and transport

Requirements regarding size and weight vary depending on the application. Compact models are suitable for everyday use, whilst larger, high-capacity power banks are designed for longer journeys or professional use.

Specific regulations apply to air travel: power banks may only be carried in hand luggage, generally up to a capacity of 100 Wh. For higher capacities, approval from the airline is required.

Lifespan and sustainability: correct usage matters

The lifespan of a power bank depends largely on usage patterns. Deep discharges, prolonged full charges and extreme temperatures accelerate the ageing of the battery cells. A charging range between 20 and 80 per cent is considered optimal for preserving the cells.

Disposal is also a safety concern: due to the lithium batteries they contain, power banks must not be disposed of in household waste. Instead, they must be returned via collection points or specialist retailers.

Conclusion: Safety as a key purchasing criterion

Power banks are more than just simple accessories – they are mobile energy storage devices with safety-critical potential. Those who look for certified quality, suitable performance parameters and transparent manufacturer information when purchasing can reliably enjoy the benefits of mobile power supply.

The recommendations from TÜV SÜD show that technical specifications alone are not enough. It is only through the combination of performance, safety and quality that a product is created which meets the demands of an increasingly mobile everyday life.