Comparison Choetech B661 vs Voltero S50

The capacity of a powerbank indicates the amount of energy it can store and is usually specified in two formats in the specifications — mAh and Wh. The mAh value is more familiar to most buyers and helps quickly understand the class of the model, while Wh more accurately reflects the total energy reserve and is more convenient for a more accurate comparison of devices. For example, a powerbank with 10000 mAh usually has about 37 Wh, a model with 20000 mAh — approximately 74 Wh, and a version with 30000 mAh — about 111 Wh. The higher these values, the more charges for a smartphone, headphones, watch, or other devices can be expected, but the larger, heavier, and usually more expensive the device becomes. At the same time, it is important to remember that the actual output is always lower than the nominal figures due to energy conversion losses. Therefore, capacity is one of the main parameters that immediately shows whether the powerbank is suitable for a day's backup or for more serious autonomous use.

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 power supplied by the power bank in wireless charging mode.

In accordance with the name, with such charging, energy is transferred to the device being charged literally via the air. However the range of such a transmission is only a few centimeters, so the gadget usually has to be placed directly on the power bank. However, it's still much easier and more convenient than fussing with wires, and the connectors don't wear out.

As for the power, the higher it is, the faster the external device can be charged. Initially, wireless technologies did not differ in power, but nowadays, even for power banks, the minimum is actually 5 W — this is comparable to the power of a modest, but far from the weakest USB port. There are also models with 10 W — this is comparable to the highest power that can be achieved at the USB output in a standard format, without the use of special fast charging technologies.

Of course, in order to use all the possibilities of wireless charging, the charging gadget must also support the appropriate power.

The number of USB-A ports available for charging smartphones, headphones, accessories, and other devices. This format is still in demand because USB-A is widely used and fits a large number of existing cables and devices, although it usually falls behind USB-C in terms of relevance and power. A single USB-A output is typically sufficient for basic everyday use, while two, three, four, or more are convenient for connecting multiple gadgets simultaneously.

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 power on USB-A1 port shows the maximum output power of the main USB-A port, which among USB-A connectors is usually the most powerful. Values around 10 – 18 W are typically sufficient for regular or fast charging of smartphones, 22.5 – 33 W are already interesting for faster charging of compatible models, while higher values for USB-A are significantly rarer than for USB-C. Compared to USB-A2, USB-A3, or USB-A4, it often makes more sense to connect the most demanding device to USB-A1 if maximum speed from this type of port is needed.

However, the USB-A format itself is already less promising today than USB-C, so such a port is more often used for smartphones, headphones, watches, speakers, and other mobile devices rather than heavy-duty applications like laptops.

The maximum power of the second USB-A output, which is usually slightly less than USB-A1, but is still suitable for charging smartphones, accessories, and other everyday devices.

Availability of additional ports for charging gadgets. In most cases, standard USB-C and USB-A ports are sufficient. Here, the focus is primarily on built-in microUSB and Lightning cables, which are auxiliary rather than primary.