Real capacity
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.
Max. power (per 1 port)
The maximum power that the power bank, theoretically, is capable of delivering to one rechargeable device. Usually, this power is achieved under the condition that no other device is connected to the battery (although exceptions to this rule are possible). And if you have ports with different charging currents or support multiple fast charging technologies, this information is given for the most powerful output or technology.
For modern power banks, a power of
10 watts or less is considered quite low; among other things, it usually means that the device does not support fast charging. Nevertheless, such devices are inexpensive and often turn out to be quite sufficient for simple tasks; Therefore, there are many models with similar specs on the market. The power of
12 – 15 W is also relatively small,
18 W can be called the average level,
20 – 25 W and
30 – 50 W is already considered an advanced level and in some solutions this parameter may
exceed 60 W.
In general, higher power output has a positive effect on charging speed, but in fact there are a number of nuances associated with this parameter. Firstly, not only the power bank, but also the gadget being charged should support the appropriate power — otherwise the speed of the process will be limited
...by the specs of the gadget. Secondly, in order to use the full capabilities of the power bank, it may be necessary for it to be compatible with certain fast charging technologies (see "Fast Charging").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.
Features
Additional functions and features provided in the design of the power bank. Such features may include, but are not limited to,
an info display, a
USB hub mode, a photocell for
solar charging, a lighting source (
flashlight or
lamp), and a
shock -resistant body. Here's a more detailed description of each of these options:
— Info display. Own display installed on the power bank body. As a rule, it has a simple LCD matrix capable of displaying 2 - 3 characters and, in some cases, individual special icons. However, even such a screen provides a lot of additional information, makes it easier to manage the power bank and monitor its status.
— USB hub. Possibility of working as a USB hub (splitter). In this mode, the external battery’s own USB connectors act as USB inputs of a PC or laptop to which the power bank is connected. The connection itself, as a rule, is also carried out using the USB standard, and the battery can be charged. This function is convenient primarily because it allows you to use one USB port simultaneously to charge the power bank and connect a peripheral device (or even several). However, it does not hurt to make sure that the power supply of this port is sufficient to provide all these functions; and the charging speed may be quite slo
...w. If the power bank is fully charged, it can also be useful as a classic USB hub: to increase the number of ports available for connecting peripherals, and also as a kind of remote USB extension cable (for example, if there is a free USB port only on the rear panel of the system unit, which is difficult to get to).
- Flashlight. In this case, a flashlight means a built-in light source of relatively low power, usually directional (as opposed to the lamp described below). Such a source performs an auxiliary function; it can be useful, for example, for illuminating the road at night, for short-term illumination in a dark room (basement, cellar), etc.
- Lamp. Built-in light source, usually in the form of an oblong panel of several LEDs; such a panel can be made folding. Unlike flashlights (see above), lamps provide not directional, but diffused light, which has a shorter range, but covers a larger space. Such lighting can be useful, for example, for reading, for illuminating a room during a power outage, and even for creating a certain atmosphere.
- Shock protection. Enhanced protection against impacts and shocks. The specific degree of such protection may vary; it should be clarified according to the official characteristics; however, most models in this category are capable of at least transferring a fall from a height of about 1 - 1.2 m onto a flat hard surface without consequences. Well, in any case, such devices will be more resistant to mechanical stress than conventional ones. It is also worth noting that shock protection in modern power banks is most often combined with protection from dust and moisture (see above), although there are exceptions to this rule.
— Charging from the sun. Possibility of charging the power bank from the sun or other bright light source. To do this, a corresponding device is installed in the body - a solar battery (photocell). This function can be especially useful during a long stay away from civilization - for example, on a hike. And although the efficiency of solar panels in general is not very high, when exposed to bright light for a long time, you can accumulate quite a lot of energy.Waterproof
The presence
of waterproof on the body of the device. This paragraph also usually shows the specific level of such protection according to the IP standard. The two digits in the IP designation indicate levels of protection against adverse factors. In this case, waterproof is indicated by the last digit, but the first characterizes the level of resistance to dust and other contaminants. In modern powerbanks, you can find the following levels of protection against contamination:
5 — dust resistance (dust can get inside in small quantities that do not affect the operation of the device);
6 - dustprooof (dust does not penetrate inside at all).
Lower levels of protection are not indicated in powerbanks (such a case will no longer be dustproof, and there is no need to specify its characteristics). However, there are models where the first digit is replaced by an X — for example, IPX6. This means that this device has not been certified for dust protection, although in fact, the level of such protection may be quite high.
As for waterproofing, the options here could be:
— 2. Minimum level — protection from drops and splashes at an angle of up to 15° from the operating position of the device (usually with the screen facing up). Allows you to withstand moderate rain without strong winds.
— 3. Protection against drops at an angle of up to 60° (moderate rain with strong wind in the screen-up pos
...ition).
— 4. Protection against splashes from any direction (rain with strong wind, regardless of the position of the body).
— 5. Protection from water jets from any direction (showers, storms).
— 6. Protection from waves and strong water jets.
— 7. The minimum level that allows us to talk about water resistance. Allows you to endure short-term (up to half an hour) immersion underwater to a depth of 1 m.
— 8. Possibility of long-term (30 minutes or more) immersion to a depth of more than 1 m, with constant work in a submerged state. Specific depth and time limits may vary.
— 9. Protection from high-temperature water jets (possibility of intensive washing with hot water under high pressure).
In general, a higher level of protection, on the one hand, provides an additional guarantee in case of unfavourable situations, on the other hand, it affects at least the price, and often also the dimensions/weight of the device. We also note that the waterproof case can also be made shock-proof — this is not necessary but is often found in models designed for use in extreme conditions.
