Comparison Nomi W100 vs Nomi E150

The higher the battery capacity, the more energy the power bank is able to accumulate and then transfer when charging to gadgets connected to it. But it should be borne in mind that not all of the accumulated energy goes specifically to charging – part of it is spent on service functions and inevitable losses in the process of transmission. So in the specifications, the real capacity of the power bank is also often specified. If there is no data on real capacity, then when calculating it is worth proceeding from the fact that it is usually somewhere 1.6 times lower than the nominal one. For example, for a model with a nominal capacity of 10,000 mAh, the actual value will be approximately 6300 mAh.

As for the specific values of the nominal capacity, then in models with the lowest performance it is 5000 – 7000 mAh and even less ; such power banks are suitable as a backup source of energy for 1 – 2 smartphone charging with a not very capacious battery or other similar gadget. The 10,000 mAh solutions are the most popular nowadays – in many cases, this option provides the best price-capacity ratio. The 20,000 mAh and 30,000 mAh options are also very common. But even a capacity of 40,000 mAh or more, thanks to the development of modern...technology, is quite common.

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-A ports for charging connected gadgets. This type is gradually being replaced by USB type C, however, most models still use USB-A as the main output. This is also indicated by the number of corresponding ports. Classic are 2 USB-A outputs. However, there are also compact models for 1 output, and more impressive ones with 3 and 4 USB-A(even more).

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.

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.

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.