The main feature of a bank is its capacity, so you should always pay attention to this parameter when buying a new device.
During the operation or purchase of such a product by hand, it becomes necessary to check the product, that is, to determine the ability to accumulate a certain amount of electricity. This article explains in detail how to measure the capacity of a bank in different ways.
What power supply is in the Power Bank
Before you start measuring the capacity of a portable energy storage device, you should know exactly how the device is arranged. The power bank consists of a thin case in which several ordinary cylindrical batteries are installed, which are connected together in parallel.
In this case, the capacities of all the elements add up, which allows you to charge a smartphone or phone several times in a row from such a product without having to install a portable battery to recharge it.
In addition to the batteries, there is a controller in the bank that will disable charging of the cells when a certain level is reached. In addition, many devices are equipped with a light indication indicating the level of charge or discharge of the internal batteries.
As a rule, rechargeable lithium batteries are installed in banks. 18650 batteries . Depending on the manufacturer, the capacity of these power sources can vary widely. For this reason, it will be useful to control this parameter during operation or immediately after purchasing a bank.
Where is the declared capacity indicated
The capacity of the cells of the 18650 battery is always indicated on the body of the power source, but for this purpose it will be necessary to disassemble the product. Such a procedure cannot be carried out without the use of brute physical force, which can cause irreparable damage to the appearance of the product.
It is much easier to determine the capacity declared by the manufacturer by studying the instructions for use. On the packaging, this information can also be duplicated, so if the original bank box is kept, you can easily determine the nominal value of this external battery setting.
How to check the capacity of a bank
The capacity of the bank can be checked in several ways. The most popular method is the multimeter method.
Using a multimeter
Multimeter is a universal device with which you can easily measure resistance, voltage, or current. You can also determine the capacitance with the help of this device, but for this you need to perform not only measurements of some parameters, but also perform some arithmetic operations.
To check the capacity, in addition to a multimeter, you will need to select a load, for example, a small electric motor or an incandescent lamp.
You will also need to connect an ammeter between the bank and the electricity consumer. The resulting value should not exceed the maximum specified in the documentation for the portable battery.
Knowing the discharge current, in order to obtain the product capacity in mAh, it is necessary to know the real time of the device from a fully charged battery. After one hundred percent charge, the load is connected to a portable power source and the timer is activated.
The test stops when the device stops operating at full power (the incandescent lamp decreases, the motor lowers the speed, etc.). To determine the capacity, the resulting time in hours is multiplied by the current in amps.
Via USB tester
As a rule, banks are equipped with a standard USB connector, so you can use special testers to determine the capacity. Such devices are compact and inexpensive.
USB battery tester
Unlike the above method, where it was necessary to calculate this parameter, when using a USB tester, it is enough to connect it to the circuit between the charger and a completely discharged battery. When charging is complete, the device will display the actual capacity level of the internal batteries on the digital display.
The advantages of this method are its simplicity and its high measuring speed. In addition to the capacity, these devices can display in real time the voltage and strength of the current consumed.
With Smart Charges
This method will require removing the batteries from the bank case. For this purpose, you need to carefully disassemble the portable product. Then unsolder or disconnect the batteries and install them in the charger. Such a method should only be chosen if the first two methods are impossible for some reason or another.
After installing the batteries in the charger, they are fully charged, after which the built-in program will accurately calculate this parameter. If all the batteries in the battery were connected in parallel, to get the exact value of this parameter, you will need to add the capacity value obtained from each cell.
How true is the data claimed?
Unfortunately, the parameters indicated on the parcel or the bank passport often do not correspond to the actual values. There is a great risk of purchasing poor quality product when ordering goods from various online sites.
Xiaomi Mi Power Bank 3 pro 20,000
You can protect yourself a little from the acquisition of such devices if you look at the reviews of real customers who have already tested the bank after the purchase.
Purchasing products from reputable manufacturers will avoid the risk of purchasing poor quality devices. The maximum deviations of the capacity value in such devices do not exceed 10%. In addition, branded products are backed by a long term warranty, which will allow you to return money or get another product in the event of a defect.