Comparison HARPER PB-20008 vs TP-LINK TL-PB20000

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 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.

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").

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".

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.

Fast charging technologies supported by the power bank. This is primarily about charging external gadgets, but the same technology can also be used when replenishing the power bank itself.

The fast charging feature, hence the name, can significantly reduce the time spent on the procedure. This is achieved through increased current and/or voltage, as well as smart process control (at each stage, the current and voltage correspond to the optimal parameters).

Fast charging is especially important for devices with high-capacity batteries that take a long time to charge normally. However, to fully use this feature, the power source and the gadget being charged must support the same charging technology; at the same time, different technologies are not compatible with each other, although occasionally there are exceptions. The most popular fast charging formats these days are QuickCharge (versions 3.0, 4.0 and 4.0+), Power Delivery (Power Delivery 3.0 and Power Delivery 3.1), Pump Express, Samsung Adaptive Fast Charging, Huawei Fast Charge Protocol, Huawei SuperCharge Protocol..., OPPO VOOC, OnePlus Dash Charge ; Here are the specific features of these, as well as some other options:

— Quick Charge (1.0, 2.0, 3.0, 4.0, 5.0). Technology created by Qualcomm and used in gadgets with Qualcomm CPUs. The later the version, the more advanced the technology: for example, Quick Charge 2.0 has 3 fixed voltage options, and version 3.0 has a smooth adjustment in the range from 3.6 to 20 V. Most often, gadgets with a newer version of Quick Charge are also compatible with older devices for charging, but for full use, an exact match in versions is desirable.
Also note that certain versions of Quick Charge have become the basis for some other technologies. However, again, the mutual compatibility of chargers/power banks and gadgets supporting these technologies needs to be clarified separately.

— Pump Express. Own development of MediaTek, used in portable devices with CPUs of this brand. Also available in several versions, with improvements and additions as it develops.

— Power delivery. Native fast charging technology for the USB type C connector. Used by many brands, found mainly in chargers (including power banks) and gadgets using this type of connector. Presented in several versions.

— Samsung Adaptive Fast Charging. Samsung's proprietary fast charging technology. It has been used without any changes since 2015, in light of which it looks quite modest compared to newer standards. Nevertheless, it is able to provide good speed, especially in the first 50% of the charge.

— Huawei FastCharge Protocol. One of Huawei's proprietary technologies. Formally similar to Quick Charge 2.0, but used with both Qualcomm and other brands of mobile processors, so compatibility is not guaranteed. In general, it is considered obsolete, gradually being replaced by more advanced standards like the SuperCharge Protocol.

— Huawei SuperCharge Protocol. Another proprietary technology from Huawei introduced in 2016; for 2021 is available in several versions. In some devices, the power of such charging exceeds 60 V — not a record, but quite an indicator.

— Oppo VOOC. OPPO technology, used both in branded smartphones and in equipment from other brands. Available in several versions; The latest (for 2021) version of SuperVOOC is for 2-cell batteries and is sometimes listed as a separate technology called Oppo SuperVOOC Flash Charge.

— OnePlus Dash Charge. A relatively old proprietary standard from OnePlus. An interesting feature is that in some gadgets, the effectiveness of Dash Charge is practically independent of the use of the screen: when the display is on, the battery charges at almost the same rate as when it is off. Technically a licensed version of OPPO's VOOC, however, these technologies are not compatible. Since 2018, Dash Charge has been phased out by Warp Charge, but this newer technology is still rare in separately sold chargers and power banks.

— PowerIQ. Technology developed by the Anker brand. The key feature of PowerIQ is that it is not a standalone standard, but a combined format of operation that combines a wide range of popular fast charging formats. In particular, version 3.0 claims the ability to work with Quick Charge, Power Delivery, Apple Fast Charging, Samsung Adaptive Fast Charging and others.

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.

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.