18650 battery capacity test method

The 18650 battery is a conventional battery model, and it is also very common in daily life. The remaining capacity of the 18650 battery is a question that many people care about. How to accurately measure the capacity of the 18650 battery? Now the author shares several 18650 battery capacity test methods to everyone, so that everyone can use non-professional methods to quickly evaluate battery capacity; 18650 lithium battery is a very common standard specification lithium battery, which is widely used in digital 3C products, In many industries and fields such as electric bicycles and power tools, its unique safety can ensure that it will not explode in extreme environments. Compared with polymer lithium batteries, cylindrical 18650 lithium batteries are safer. At the same time, because of the high utilization rate of 18650 single-cell batteries, over a period of time, the capacity of single-cell 18650 batteries sold through e-commerce platforms has not been marked according to the regulations, and it has become more and more intense, although the current 18650 lithium is known The maximum capacity of the battery can only reach the limit of 3500mAh. The market is still flooded with 5000mAh or even 8000mAh 18650 lithium batteries, so how do we identify the fake capacity 18650 lithium batteries? The following lithium battery PACK factory describes several capacity test methods for 18650 lithium batteries. Standard method: measure with a battery sub-volume detector, first charge the lithium battery to 4.20V in a constant temperature environment (25°C), leave it for 1 hour and discharge at a constant current rate of 0.2 times. For example, with a capacity of 1000mAh, discharge at a constant current of 200mA. To 2.75V cut-off (or according to the discharge cut-off voltage specified in the corresponding model specification of the lithium battery), calculate the time and time * constant current u003d battery capacity. This is a standard method in accordance with the national standard lithium battery regulations. If it is a Ni-MH battery, the same is true. The discharging and full charging methods can be in accordance with the nickel-hydrogen battery standard. There are some chargers on the market that can measure batteries. They have a built-in program that can automatically calculate the capacity of the battery through discharge through a constant current method. But the accuracy rate is not high, but the results can still be used as a reference. The main reason is that the accuracy of the hardware is limited, and it is not in a constant temperature environment. The difference in temperature will have a greater impact on the capacity of the lithium battery. The test results show that when the environmental temperature difference is 10°C, the battery capacity tested has a large error. Non-professional method one): Use a charger with recording charging capacity to charge the dead battery. If the charged capacity is not as high as the capacity marked on the battery, you need to be wary that it is a fake battery. Of course, the charged battery The capacity does not represent the actual capacity of the battery, but it is sufficient as a reference. Normally, the capacity of the charged battery is about 500-1000mAh larger than the actual capacity of the battery. This is related to the capacity of the battery itself.　　 Non-professional method two): Use a smart battery charger with discharge function to perform charge and discharge measurement. The result obtained by this method is closer to the actual capacity of the battery. The very accurate chargers on the market can achieve a measurement error within 3%. Non-professional method three): Without any equipment, we can also calculate by manual measurement, such as using bulb discharge or equipment discharge, using a bulb with a rated W number to connect to the battery, power consumption of the lithium battery, and record The total discharge time can also record the approximate lithium battery capacity according to the power and discharge time. This result is only an approximation. But it is used to find fake batteries and rubbing more than enough. Non-professional method four): Use a load meter to record the discharge time, and you can also calculate the corresponding capacity. This is also a relatively reliable method. The 18650 battery has a wide range of applications and can be seen almost everywhere in daily life, so it is necessary for us to pay attention to the quality and safety of the 18650 lithium battery used. The methods introduced above can at least allow users to identify fake lithium batteries. 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