Battery capacity
Battery capacity in watt-hour. These units of measurement are less popular than MilliAmp hour, but are more physically correct: they accurately describe the amount of energy accumulated by the battery. Thanks to this, in terms of capacity in Wh, it is possible to compare batteries with different rated voltages (while for mAh this is not allowed — additional calculations must be carried out using special formulas). At the same time, Wh can be converted to mAh without much difficulty if the battery voltage is known (for power banks this is in most cases 3.7 V): to do this, the capacity in Wh must be divided by the voltage and multiplied by 1000.
USB type С
USB type C is a popular type of USB connector characterized by its small size, reversible design, and fairly advanced (in theory) capabilities. If there are several connectors of this type, the first one is considered to be capable of delivering more power.
It is characterized by the rated power supplied by the power bank when a load is connected to the first or only
USB type C output and the current strength. The speed of the charging process directly depends on the power. It is traditionally calculated by multiplying the current by the voltage; However, the standard voltage for USB power is 5 V, so current is considered to be the main indicator of power.
The magnitude of the charging current directly determines the power supplied to the device being charged - and, accordingly, the maximum speed of the process (in practice, it may be lower if the device being charged has strict restrictions on the charge current). Power is also determined by the supply voltage (the number of watts is calculated by multiplying amperes by volts); While the standard USB output voltage is 5V, many fast charging technologies (see below) use higher voltages. Therefore, in the notes to this paragraph, the maximum power on the USB type C connector is also indicated.
As for specific values, the most popular option for USB type C outputs in modern power banks is
3 A. There are also other values - both sma
...ller ( 2.4 A, 2.1 A and 2 A) and larger ones - but noticeably less frequently.USB A
A standard
USB A port is characterized by the rated power supplied by the power bank when a load is connected to the first or only USB A output and the current strength. If there are several connectors of this type, the first one is considered to be capable of delivering more power.
The speed of the charging process directly depends on this indicator. Power is traditionally calculated by multiplying current by voltage; However, the standard voltage for USB power is 5 V, so current is considered to be the main indicator of power.
The charging power and, accordingly, the speed of the process depend on the current strength. Nowadays, on USB ports, a current of
2 A or
2.1 A is considered basic and quite modest,
2.4 A and
2.5 A are average,
3 A and
more are noticeably above average, and certain fast charging technologies allow you to achieve values of
4 A. 4.5 A and
5 A. However, it is worth considering that to operate at high current, such an opportunity must be provided not only in the power bank, but also in the gadget being charged. So when purchasing a model, it doesn’t hurt to check whether the devices being charged suppo
...rt high charge currents.
It is also worth noting two nuances associated with the presence of multiple USB charging ports. Firstly, they may differ in the current they produce. This allows you to select the optimal connector for each device: for example, to quickly charge a tablet with a capacious battery, it is desirable to have a higher current, and a device with a low charging current can be connected to a “weaker” port, so as not to create unnecessary load on the battery and controller. The second caveat is that if all USB connectors are used simultaneously, the current supplied by each of these connectors may be lower than the maximum; in other words, not all power banks allow you to simultaneously use USB ports at the maximum possible power. You can understand whether such a possibility exists by looking at the charge power (see below); if the charge power is not indicated, you should refer to detailed documentation from the manufacturer.USB A (2nd)
Characteristics of the second USB A port. Read more in the paragraph above.
Fast charge
Fast charging technologies supported by the power bank. This is primarily about charging external gadgets, but the same technology can also be used when replenishing the power bank itself.
The fast charging feature, hence the name, can significantly reduce the time spent on the procedure. This is achieved through increased current and/or voltage, as well as smart process control (at each stage, the current and voltage correspond to the optimal parameters).
Fast charging is especially important for devices with high-capacity batteries that take a long time to charge normally. However, to fully use this feature, the power source and the gadget being charged must support the same charging technology; at the same time, different technologies are not compatible with each other, although occasionally there are exceptions. The most popular fast charging formats these days are
QuickCharge (versions
3.0,
4.0 and
4.0+),
Power Delivery (
Power Delivery 3.0 and
Power Delivery 3.1),
Pump Express,
Samsung Adaptive Fast Charging,
Huawei Fast Charge Protocol,
Huawei SuperCharge Protocol..., OPPO VOOC, OnePlus Dash Charge ; Here are the specific features of these, as well as some other options:
— Quick Charge (1.0, 2.0, 3.0, 4.0, 5.0). Technology created by Qualcomm and used in gadgets with Qualcomm CPUs. The later the version, the more advanced the technology: for example, Quick Charge 2.0 has 3 fixed voltage options, and version 3.0 has a smooth adjustment in the range from 3.6 to 20 V. Most often, gadgets with a newer version of Quick Charge are also compatible with older devices for charging, but for full use, an exact match in versions is desirable.
Also note that certain versions of Quick Charge have become the basis for some other technologies. However, again, the mutual compatibility of chargers/power banks and gadgets supporting these technologies needs to be clarified separately.
— Pump Express. Own development of MediaTek, used in portable devices with CPUs of this brand. Also available in several versions, with improvements and additions as it develops.
— Power delivery. Native fast charging technology for the USB type C connector. Used by many brands, found mainly in chargers (including power banks) and gadgets using this type of connector. Presented in several versions.
— Samsung Adaptive Fast Charging. Samsung's proprietary fast charging technology. It has been used without any changes since 2015, in light of which it looks quite modest compared to newer standards. Nevertheless, it is able to provide good speed, especially in the first 50% of the charge.
— Huawei FastCharge Protocol. One of Huawei's proprietary technologies. Formally similar to Quick Charge 2.0, but used with both Qualcomm and other brands of mobile processors, so compatibility is not guaranteed. In general, it is considered obsolete, gradually being replaced by more advanced standards like the SuperCharge Protocol.
— Huawei SuperCharge Protocol. Another proprietary technology from Huawei introduced in 2016; for 2021 is available in several versions. In some devices, the power of such charging exceeds 60 V — not a record, but quite an indicator.
— Oppo VOOC. OPPO technology, used both in branded smartphones and in equipment from other brands. Available in several versions; The latest (for 2021) version of SuperVOOC is for 2-cell batteries and is sometimes listed as a separate technology called Oppo SuperVOOC Flash Charge.
— OnePlus Dash Charge. A relatively old proprietary standard from OnePlus. An interesting feature is that in some gadgets, the effectiveness of Dash Charge is practically independent of the use of the screen: when the display is on, the battery charges at almost the same rate as when it is off. Technically a licensed version of OPPO's VOOC, however, these technologies are not compatible. Since 2018, Dash Charge has been phased out by Warp Charge, but this newer technology is still rare in separately sold chargers and power banks.
— PowerIQ. Technology developed by the Anker brand. The key feature of PowerIQ is that it is not a standalone standard, but a combined format of operation that combines a wide range of popular fast charging formats. In particular, version 3.0 claims the ability to work with Quick Charge, Power Delivery, Apple Fast Charging, Samsung Adaptive Fast Charging and others. 
