Comparison Trust Primo Power Bank 10000 vs Proda Power Box PPL-11

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.

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.

The type of own batteries installed in the power bank. Lithium-ion(Li-Ion) or lithium-polymer(Li-Pol) batteries are most commonly used today. Other options are less common — solutions based on nickel-metal hydride(Ni-Mh) batteries, as well as on LiFePO4 type cells. In addition, a rather promising development has appeared relatively recently — graphene batteries; however, as of early 2021, they are just beginning to be introduced into mass production. Here are the main features of each of these varieties:

— Li-Ion. Lithium-ion technology allows you to create quite capacious batteries of small dimensions and weight. In addition, such elements are easy to use (the main operating parameters are regulated by the built-in controller), have a high charge speed and are practically not affected by the "memory effect" (reduction in capacity when charging an incompletely discharged battery). The main disadvantage of lithium-ion batteries is a rather narrow range of permissible ambient temperatures. This is not a problem in urban usage, when the power bank is used mainly indoors and is carried in a pocket or in a bag; but for less favorable conditions (such as long hikes in the cold season), it is worth choosing models with good thermal insulation. You can also find information that lithium-ion batteries are prone to fires and even explosions; however, this is usually due to...failures in the embedded controllers, and these controllers are also constantly being improved, and nowadays the risk of such an accident is so low that it can actually be neglected.

— Li-pol. Further development and improvement of the lithium-ion technology described above; the main difference is the use of a solid polymer electrolyte instead of a liquid one (hence the name). This made it possible to achieve even greater capacity without increasing the dimensions, as well as to reduce the potential for fires and explosions during abnormal operation. On the other hand, lithium-polymer batteries are somewhat more expensive than lithium-ion batteries and are even more sensitive to temperature disturbances.

— Ni-Mh. Nickel-metal hydride batteries are distinguished by their reliability and a wide range of permissible temperatures, however, with the same dimensions, they are inferior in capacity to lithium-ion (and even more to lithium-polymer) batteries, and they also require certain specific operating rules to be observed. In addition, it is worth noting that Ni-Mh technology is well suited for removable batteries. It is in this format that such batteries are most often used: power banks of the Ni-Mh format are usually adapters with slots for several replaceable elements of a standard size (for example, AA). In this case, usually, several corresponding removable batteries are included in the kit, however, if desired, they can be replaced with other elements — these can even be disposable batteries from the nearest store. Such an opportunity can turn out to be very useful if the power bank is out of juice at an unfortunate moment, but there is no way to charge it; in addition, worn-out batteries can be replaced with fresh ones without changing the entire device.

— Li-FePO4. Another modified version of the Li-Ion batteries described above, the so-called "lithium iron phosphate". The advantages of such cells over classical lithium-ion ones are, first of all, a stable discharge voltage (until the energy is exhausted), high peak power, long service life, resistance to low temperatures, stability and safety. In addition, due to the use of iron instead of cobalt, such batteries are also safer to manufacture and easier to dispose of. At the same time, they are noticeably inferior to the classic lithium-ion ones in terms of capacity, and they are more expensive, which is why they are rarely used.

— Graphene. Batteries based on graphene — a carbon film one atom thick. The battery itself consists of a set of such films, between which silicon plates are laid, and lithium cobaltate or magnesium oxide is used as an anode. This design provides a number of advantages over the earlier batteries described above. First, graphene technology provides a high charge density, which allows you to create capacious and at the same time light and compact batteries. Secondly, for the production of such batteries, fewer rare resources are needed than for the same lithium ones; and the production itself is more environmentally friendly. Thirdly, such batteries are not prone to overheating and explosions when overloaded or damaged. On the other hand, graphene power supplies take a long time to charge and are not durable. However, this technology is still developing, and in the future it is likely that these shortcomings will be eliminated — completely or at least partially.

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").

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.

The number of charge-discharge cycles that the battery can withstand without significant loss of performance.

During operation, batteries wear out, and because of this, their specs (primarily capacity) noticeably deteriorate. Battery life is usually measured in charge-discharge cycles. The features of counting cycles are described in detail in special sources, but here we note that not always models with the same claimed resource turn out to be equally durable in fact. The fact is that different manufacturers may understand “significant loss of performance” differently: for example, one brand can indicate a resource up to a 20% decrease in capacity, the second — up to a 60% decrease. Therefore, when choosing, it makes sense to focus not only on pure numbers, but also on other sources — test results, reviews, etc.

Also note that battery life can be noticeably reduced if the operating conditions are violated — for example, in case of overheating or excessive cold.

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.