Comparison ATRIA WPD-100 vs Romoss Sense 8PS Pro

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 number of modern ports USB-C and built-in USB-C cables that can be used to charge smartphones, tablets, headphones, consoles, and other current devices. This format is particularly convenient today because USB-C has become the main connector for most new devices and usually supports higher charging power than USB-A. One USB-C output is usually enough for everyday use, while two and three are convenient if you need to connect several gadgets at the same time.

The power capacity of the main USB-C port, which among USB-C connectors is typically the most powerful. This specification is especially important for smartphones with fast charging, tablets, portable consoles, and laptops that require increased power supply.

Values around 18 – 30 W are usually sufficient for fast charging smartphones, 45 – 65 W are suitable for portable consoles, some ultrabooks, and other more demanding devices, and 100 W and above are even designed for powerful laptops and heavy loads.

Maximum output power of the second USB-C port, which usually lags behind USB-C1, but can still be suitable for fast charging smartphones, portable consoles, and other modern devices.

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".

The power in watts at which the power bank is charged under normal conditions.

The higher the charging power, the less time it takes to charge (given the same battery capacity). For example, fast charging of a power bank typically means a charging power of 30W or more. However, this parameter does not directly affect compatibility with charging devices: modern portable batteries can work with chargers of both higher and lower power. In the first case, the battery controller will automatically limit the charging current, while in the second case, charging will simply take more time.

The time required to fully charge a battery discharged “to zero”. Features of the charging process in different models may be different, respectively, and the time required for this may differ markedly even with the same capacity.

Fast-charging batteries tend to be more expensive. Therefore, choosing this option makes sense if you do not have much time to replenish your energy supply — for example, for hiking. However, keep in mind that charging at full speed may require a charger that supports certain fast charging technologies (see below).

It must also be said that in most modern batteries, the charging speed is uneven — it is highest at the several first percent from zero, then gradually decreases. Therefore, the time required to replenish the energy supply by a certain percentage will not be strictly proportional to the total claimed charge time; moreover, this time will depend on how much the battery is already charged at the time the procedure starts. For example, charging from 0 to 50% will take less time than from 50 to 100%, although both there and there we are talking about half the capacity.

Low current charging allows you to seamlessly charge devices that do not require high current. This allows you to extend the life cycle of the devices and protect them as much as possible during charging. Such devices include smartwatches, headphones, headsets, etc.

Types of cables and/or adapters for charging external devices included with the power bank.

The type of these cables is indicated by the plug used to connect to the charging gadget; the connection to the power bank itself is usually through a standard USB-A or USB type C output. It should be emphasized that this refers to removable cables/adapters; types of built-in charging cables are specified separately (if available — see below).

Overall, this parameter allows you to assess the capabilities of the power bank available "out of the box," without purchasing additional accessories. As for specific interfaces, most external batteries these days come with cables/adapters for microUSB, USB type C, and/or Lightning; more specific connectors are extremely rare. Here are the features of the most popular options:

— microUSB. A connector extremely common in modern portable gadgets. It is less convenient than the newer USB type C and has fewer working characteristics, but it still maintains popularity.

— USB type C. A relatively new standard for miniature USB connectors, used for charging both in portable devices and larger ones — particularly some ultra-compact laptops. Physically, it differs from microUSB with slightly larger sizes and a reversible design, allowing the plug to be connected in either direction. In terms of performance, USB...type C is notable for better compatibility with fast-charging technologies: more such technologies can be used with it, and Power Delivery was originally designed for this connector. However, having a USB type C cable does not necessarily mean support for fast charging.

— Lightning. A standard proprietary connector used in compact Apple gadgets; such technology is not found with other manufacturers.

Note that if several types of included cables/adapters are specified in the characteristics, the specific format of such accessories may vary. For example, the "microUSB plus USB type C" option could mean two separate cables, one cable with two plugs, a cable with one connector plus an adapter for another, etc.