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-A
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).
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.
Body material
The main material used in the the body of a power bank.
In addition to traditional
plastic, nowadays, external batteries are produced in cases made of more advanced and/or "prestigious" materials. Of these materials,
aluminium is the most widely used; also you can find products made of
steel, zinc,
leather,
fabric and even
wood. Here are the main features of each option:
— Plastic. The most popular material for the bodies of modern power banks. Plastic, on the one hand, is inexpensive, on the other hand, it is quite durable and has a small weight, on the third hand, it makes it easy to create cases of any shape and colour, which is especially important for devices with an unusual design. In terms of strength and reliability, ordinary plastic is somewhat inferior to metals; however, in everyday use, this difference is not critical — except that scratches on such a case will appear faster. And for extreme conditions, cases can be produced from special impact-resistant plastic.
— Aluminium. Aluminium alloy housings are highly durable and lightweight; in addition, they look stylish, and the appearance is retained for a long time due to scratch resistance. The main disadvantage of aluminium is that it is more expensive than plastic.
...— Steel. Steel is notable for its high durability and reliability; according to these indicators, it surpasses even aluminium, not to mention plastic. On the other hand, this material has a significant weight, and therefore is used much less frequently.
— Leather. Solid body (plastic or metal) with additional leather cover. Such a coating does not affect the functionality and plays a purely aesthetic role: it gives the device a stylish and eye-catching appearance, allowing you to turn the power bank into a stylish accessory. However, note that in the design of such products (especially inexpensive ones), artificial leather (leatherette) is often used, which is noticeably inferior to natural leather in reliability, durability, and sometimes in appearance. Genuine leather, on the other hand, significantly affects the price — its cost can be more than half of the total price of the entire power bank.
— Fabric. A hard case (usually plastic) with a fabric outer covering. Such a coating not only gives the device a rather original appearance, but also gives some practical advantages: the fabric is pleasant to the touch and does not slip in the hand, which reduces the risk of dropping the power bank. On the other hand, various contaminants are poorly removed from such a surface, it has no fundamental advantages over plastic or metal, but it costs much more. Therefore, fabric cases are not very popular.
— Wood. Another design material used mainly for its original appearance than practical advantages. Nevertheless, wood is not inferior to plastic; and some users also consider the natural origin of this material to be an important advantage. On the other hand, wooden cases do not have noticeable advantages over plastic ones, and they cost much more.
— Zinc. Zinc alloys are similar in most properties to the aluminium alloys described above, however, for a number of reasons (in particular, due to the greater complexity in production), they are used extremely rarely.
