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 C
The total number of
USB type C ports for charging connected gadgets. By 2023, they have become very popular. However, power banks are equipped mainly with
one output port of the corresponding format.
Models with 2 USB type C outputs have not yet gained such popularity.
Power output (all ports)
The total charge power provided by the power bank on all connectors overnight - when devices are connected simultaneously to all charging ports.
This parameter is given due to the fact that the total charge power does not always correspond to the sum of the maximum powers of all available ports. The built-in battery of a power bank often has its own limitation on the output power. Therefore, for example, in a model with two 18 W USB ports, each total charge power can be the same 18 W. Note that the distribution of power among the connectors may be different: in some models it is divided equally, in others it is divided in proportion to the maximum current strength (if it differs on different ports). These nuances should be clarified using the detailed characteristics of the charging connectors.
If you plan to regularly use all power bank connectors at once, you should pay attention to this indicator.
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.Power bank charging inputs
The type of input used to charge the power bank's own battery. Simply put, this paragraph indicates which connector on the cable you need to charge the power bank. At the same time, some models provide several inputs for charging at once, which simplifies the search for a cable. Also note that for models with a built-in power bank charging connector (see below), the type of this connector is specified separately.
Most often in modern power banks there are standard connectors
microUSB,
USB type C and/or
Apple Lightning. A lot of accessories are produced for such connectors — cables, network and car chargers, adapters, etc.; so there is usually no difficulty in finding a source of energy. Less common are models with
DC input, they are usually equipped with their own power supply (or at least a cable under such a connector). Here is a more detailed description of the different types of inputs:
— microUSB. A smaller version of the USB connector, still very popular in portable tech, despite the active spread of the more advanced USB type C. It has relatively modest capabilities — in particular, it does not allow the implementation of some advanced fast charging technologies. On the other hand, it is very easy to find a source of energy for such a connector: both modern and many of the frankly outdated cables and chargers are
...suitable for it.
— USB type C. A miniature type of USB connector, positioned, among other things, as the successor to microUSB. The most noticeable improvement is the reversible design, which allows you not to worry about which side of the plug is inserted into the connector. However, in the case of power banks, this is not the only or even the main advantage: USB type C has more extensive capabilities, allows more powerful currents and use a wider range of fast charging technologies (and Power Delivery was originally created specifically for this connector). Note that in some models the same connector of this type can be used both as an input for charging the battery and as an output for charging external devices — moreover, with automatic switching between these modes.
— Apple Lightning. Initially, this connector is designed for portable gadgets made by Apple. However, in the case of power banks, it can also be found in third-party devices: the idea is that the presence of Lightning allows you to charge an external battery using a cable from an iPhone or iPad and eliminates the need to look for a separate wire. For a number of reasons, this charging input is rarely used as the only one, more often it is provided in addition to microUSB or USB type C (see above).
— DC input. DC is a standard covering several types of connectors at once. Their common feature is a signature round shape, but the diameter, rated voltage and power can be different. In this sense, such connectors are not as convenient as USB type C, Lightning and other generally accepted standards — with a DC socket, it is best to use a native power supply (usually it comes bundled right away), and finding a third-party power source can be a problem. On the other hand, inputs of this type have practically no power limitations, it is easier to achieve high power supply with them than with the connectors described above. Therefore, DC inputs are used mainly in high-capacity power banks, where charging through a "weaker" interface would take an unreasonably long time. However, such models can also be equipped with standard microUSB or USB type C connectors "just in case".Power bank charge current via USB
Nominal charge current supported by the power bank when charging its own battery via microUSB, USB type C, or Lightning (see "Battery charging inputs").
This is the maximum and, in fact, the recommended power bank charge current. If the amperes supplied by the power source exceed this value, the charge current will still be limited by the built-in controller to avoid overloading. And using a charger with a lower output current, in turn, will lead to an increase in charging time.
Data on the charge current via USB (Lightning) is especially important due to the fact that modern power banks are usually not equipped with their own chargers for these inputs, and energy sources must be separate. On the other hand, if a high charging speed is not critical for you, you can ignore this parameter: any USB connector is suitable as a power source for the corresponding power bank inputs.
Full charge time
The time required to fully charge a battery discharged “to zero”. Features of the charging process in different models may be different, respectively, and the time required for this may differ markedly even with the same capacity.
Fast-charging batteries tend to be more expensive. Therefore, choosing this option makes sense if you do not have much time to replenish your energy supply — for example, for hiking. However, keep in mind that charging at full speed may require a charger that supports certain fast charging technologies (see below).
It must also be said that in most modern batteries, the charging speed is uneven — it is highest at the several first percent from zero, then gradually decreases. Therefore, the time required to replenish the energy supply by a certain percentage will not be strictly proportional to the total claimed charge time; moreover, this time will depend on how much the battery is already charged at the time the procedure starts. For example, charging from 0 to 50% will take less time than from 50 to 100%, although both there and there we are talking about half the capacity.
Low current charging
Low current charging allows you to seamlessly charge devices that do not require high current. This allows you to extend the life cycle of the devices and protect them as much as possible during charging. Such devices include smartwatches, headphones, headsets, etc.
