If you are using a powerbank (portable battery), you may have noticed that the specified capacity is often not fully achieved in practice. For example, in theory, a Powerbank of 10,000 mAh should be able to charge a 5,000 mAh phone twice. But in reality this is rarely possible.

The difference between real capacity and advertising capacity

This does not mean that manufacturers are trying to mislead you. The capacity specified in the Powerbank refers to the total energy of the lithium batteries used. However, the entire energy does not turn into “available capacity .. There are more than one reasons for this:

• Losses in Energy Transformation: Powerbank increases the energy to 5V and transmits them to the charger. However, the lithium batteries usually store energy at the level of 3.7V. This energy is converted to 5V with a mechanism called “amplifier converter ,, but energy loss is experienced during transformation.
• Bumper Capacity: Electronic devices distinguishes some of the batteries into a buffer to prevent excessive charge and discharge. Since Powerbanks work with larger batteries, they need larger buffer areas. This reduces the available capacity.
• Temperature Effect: Powerbanks produce heat during energy transfer. Since cooling mechanisms in most devices are limited, this heat leads to losses and reduces efficiency.
• NATURAL DEFINITION PROCESS: Batteries deteriorate over time and lose their capacity. Powerbanks may be worn out, even when they are available in warehouses for a long time, some of the batteries may be worn.

Understanding the nominal capacity and real capacity

Producers do not usually mention more than nominal capacity (around 60%). For example, a PowerBank of 20,000 mAh actually provides a useful capacity of approximately 12,000 mAh, which can charge a 5,000 mAh phone about two and a half times.

For a better assessment, it is a good idea to follow product reviews and user reviews. In addition, it is often a safer option to choose the products of well -known and reliable brands.