A detailed discussion on the problem of false labeling of mobile power capacity

The problem of false labeling is a headache

In the mobile power industry, false labeling has become one of the first factors that most consumers consider before purchasing. Due to the lack of current mobile power industry standards and the chaos in the industry, coupled with consumers' lack of awareness of mobile power products themselves, some consumers who want to use mobile power have concerns, such as: Is the false labeling phenomenon really common?

Whether you buy those expensive big-brand power banks or those on Taobao that cost around a hundred yuan but have a capacity of tens of thousands of mAh, I believe that most consumers who have used power banks will have this question: why, when actually using them, they always feel that the capacity is not as much as indicated on the packaging? Is this situation what we call a false labeling problem?

About the parameters of the battery

Simply put, a mobile power bank is a large-capacity, rechargeable battery. As the most important power storage unit, the battery cell is essentially no different from the mobile phone batteries we often use. Most of them use the currently very mainstream lithium-ion battery cell as a power storage unit. In order to have a deeper understanding of the characteristics of lithium batteries, we first need to understand the three basic units of milliampere-hour (mAh) for battery capacity, milliampere (mA) for current, and watt-hour (Wh) for power.

Internal battery of mobile power bank

As we all know, the basic unit for judging the capacity of lithium-ion batteries is milliampere-hour, which is defined as the current generated by full discharge under a certain discharge time. For example, 1000 milliampere-hour means that the full discharge current of this battery in 1 hour is 1000 milliamperes (mA). Milliampere-hour (mAh) is a small unit of the main unit ampere-hour (Ah), that is, 1Ah=1000mAh.

Capacity is often expressed in mAh.

Although milliampere-hour (mAh) is not a standard unit, it can be very conveniently used to measure and calculate the battery life. For example, a battery with a capacity of 1000mAh can provide power for 10 hours under ideal conditions at a constant current of 100mA.

Some batteries will indicate the charge level.

Wh is the amount of electricity, which is proportional to voltage, current and time. mAh is usually used as an indicator of battery charging and discharging. It is an indicator proportional to the charging (discharging) current and time of the battery. To make it comparable or convertible with Wh, the voltage of the battery must also be known. For example, in the figure above, the voltage is 3.7V, and the capacity is 4000mAh (4Ah). The amount of electricity in the mobile phone battery is 3.7V*4Ah=14.8Wh.

Output capacity of mobile power supply

Most mobile power banks are designed to allow users to use a simulated charging adapter to charge their mobile phones and other devices when they are out and about. In addition, the charging voltage of mainstream mobile phones is the standard voltage of the USB interface, which is 5V. Therefore, almost all mobile power banks on the market are equipped with a standard USB interface, which can provide a standard 5V output voltage.

Output interface of mobile power supply

Therefore, for a mobile power bank, the biggest function of its internal circuit board is to convert the energy of the lithium-ion battery in the 3.7V voltage state into the 5V voltage we need to use. According to the law of conservation of energy, after a lithium battery with a parameter of 3.7V/1000mAh (energy is 3.7Wh) is converted to 5V voltage, its theoretical capacity is 740mAh, that is (3.7V * 1Ah = 5V * 0.74Ah = 3.7Wh). That is, 100% conversion efficiency (3.7Wh) / (3.7Wh) = 100%.

Mobile power internal circuit board

When charging and discharging, the mobile power supply will convert part of the electrical energy into heat.

However, for mobile power supplies, the energy of the lithium battery at 3.7V voltage will be consumed by internal electronic components during the process of converting to 5V voltage, thus turning into heat energy and being wasted. Therefore, when any mobile power supply currently provides 5V voltage output, its actual output capacity must be smaller than the capacity value of the internal battery cell, that is, the battery cell capacity ≠ output capacity.

What is a false label?

After some understanding, we can see that for any mobile power supply currently on the market, its actual output capacity is smaller than the actual capacity of the internal battery.

A certain brand of mobile power bank with a capacity of 12000mAh

What we usually call the problem of false labeling refers to the fact that the actual capacity of the battery inside the power bank is less than the capacity value marked by the manufacturer. For example, a power bank with a capacity of 5000mAh marked on the product packaging has a real capacity of 4500mAh, which means that the actual battery capacity does not reach the nominal capacity value. This is the real false labeling of the power bank.

The actual total capacity of the internal battery is 8275mAh

Therefore, in the mobile power industry, what we usually call false labeling actually means that the capacity of the battery cells used in the mobile power is smaller than the capacity value stated by the manufacturer.

An industry in urgent need of standardization

Since the battery of the power bank is hidden under its shell, and the current power bank uses different circuit conversion efficiencies, some small counterfeit brands have an opportunity to increase product profits by using batteries with smaller capacity than the nominal capacity. Therefore, consumers can only determine whether the power bank is falsely labeled through third-party media reviews or by purchasing professional testing equipment.

Where is the future of mobile power supply standards?

Therefore, in the absence of a more intuitive and simple method for consumers to determine whether the internal batteries of mobile power supplies are falsely labeled, we can only hope that the country will issue corresponding mobile power supply standards and specifications as soon as possible.

Summary: In summary, for current mobile power supplies, it can be said that most manufacturers will only mark the capacity of the battery cells used in the mobile power supply as the total capacity of the product. In other words, in our actual use, this capacity value can only provide a reference for consumers. Therefore, in the current mobile power supply industry that lacks standards and norms, only if more manufacturers set an example and eliminate false labels in the true sense can this chaotic market truly develop in a healthy and stable direction. At the same time, our ZOL mobile power supply channel will continue to improve and perfect our evaluation methods. While providing real and effective data to consumers, we also hope to contribute a little to the development of the mobile power supply industry.