Comparison XO PR156 vs XO PR189

The real capacity of the power bank.

Real capacity is the amount of energy that a power bank is able to transfer to rechargeable gadgets. This amount is inevitably lower than the nominal capacity (see above) — most often by about 1.6 times (due to the fact that part of the energy goes to additional features and transmission losses). However, it is by real capacity that it is easiest to evaluate the actual capabilities of an external battery: for example, if this figure is 6500 mAh, this model is guaranteed to be enough for two full charges of a smartphone with a 3000 mAh battery and smartwatches for 250 mAh.

The capacity in this case is indicated for 5 V — the standard USB charging voltage. At the same time, the features of milliamp-hours as a unit of capacity are such that the actual amount of energy in the battery depends not only on the number of mAh, but also on the operating voltage. In fact, this means that when using fast charging technologies (see below) that involve increased voltage, the actual value of the actual capacity will differ from the claimed one (it will be lower). There are formulas and methods for calculating this value, they can be found in special sources.

The total number of USB-A ports for charging connected gadgets. This type is gradually being replaced by USB type C, however, most models still use USB-A as the main output. This is also indicated by the number of corresponding ports. Classic are 2 USB-A outputs. However, there are also compact models for 1 output, and more impressive ones with 3 and 4 USB-A(even more).

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.

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.

Characteristics of the second USB A port. Read more in the paragraph above.

Characteristics of the third USB A port. Read more in the paragraph above.

Rated power output by the power bank when the load is connected to the third USB A port. For more information about this parameter, see "Power per USB A port (1st)".

The rated power supplied by the power bank when a load is connected to the third USB port. For more information about this parameter, see “USB A current (1st)”.

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".