Power Banks - Take Your Power Source Everywhere with You

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By John R. Wilson
Last updated: May 07, 2018

The Powerbank allows you to power your phone or tablet when you're on the go.

What is a power bank?

A power bank is an additional battery that allows devices to be charged remotely from any power outlet via USB. Most commonly, the devices are used to charge smartphones and tablets. Depending on the capacity, such devices can be fully charged several times with a power bank, which also makes long-term travel possible.

How does a power bank work?

All power banks have built-in charging electronics that specify both input and output voltage. This can lead to no defect during use. The power bank is usually connected to a USB cable, which can then be used to charge any compatible device. The terminals recognize no difference to a conventional charger and behave as if they were connected to a conventional charger.


The power bank itself usually gets its power from a power outlet and is charged there in advance by the user. Only a few models alternatively offer charging by solar energy or even with a hand crank. The effectiveness leaves such solutions but unfortunately to be desired.

Advantages & Applications

The benefits of a power bank are obvious. It is possible with such a device to operate mobile devices for much longer independent of a power outlet. Keep modern smartphones, even with moderate use, hardly more than a day though, and this value can easily be multiplied with a power bank. Even if a single power bank should not be enough, you can easily take several such chargers with you. In this way, it is easily possible to operate a terminal for weeks or even months without a power outlet.


Power banks are particularly common in smartphones today. The digital all-rounder has become indispensable in our everyday lives and today no longer serve only as a device for communication but as a complete mobile entertainment center.

People are on the Internet with their smartphones, listening to music and playing games. All this puts a heavy strain on the battery, in extreme cases; the air is out of a smartphone after only two hours out. More and more users are therefore turning to the use of a power bank to achieve long battery life without compromise.

More and more users are therefore turning to the use of a power bank to achieve long battery life without compromise.

Basically, power banks are not limited to smartphones. They also lend themselves to power MP3 players, game consoles, tablets, portable speakers or even notebooks. There are no limits to the imagination here, thanks to USB ports, a wide range of compatibility is ensured.

What types of power banks are there?

The most obvious difference in power banks is in the capacity used, which is expressed in mAh (milliamp hours). The higher this value, the more energy a power bank can store. However, this is also associated with a larger case and significantly more weight. So everyone has to decide for themselves whether they would prefer to use a lightweight and compact model or take a heavy power bank in their luggage for the sake of capacity. There are also differences in the equipment.

Simple power banks offer only a single USB port and no other features. In addition, high-quality models allow the simultaneous connection of multiple devices and also often offer the user additional functions such as a flashlight.

In addition to today's widespread power banks with integrated battery, there are also models that rely on a completely different technology. These include, for example, power banks that can be operated with standard batteries. This has the advantage that on the way by the purchase of batteries always power is available, the dependence on sockets decreases even more. In direct comparison, however, this is an expensive fun and environmentally friendly is the charging in this way in any way.


A much more positive environmental balance has devices that can be charged by a solar panel. So that enough energy is available for a smartphone, the sun has to shine directly onto the collector. The use is therefore usually only useful on hot summer days. Finally, there are also mobile chargers that can be operated with a crank. The weather does not matter; the current flow is determined solely by muscle power. For today's smartphones, however, even experienced athletes bring hardly enough power to recharge the battery significantly. In times of simple mobile phones such devices were still useful, but today they have no meaning.

That's how we reviewed the power banks



No power bank is able to deliver 100 percent of its rated power to another device. In the Powerbank test, we check exactly how effectively the individual models work. At least half of their rated power should be able to make even cheap devices, the best power banks reach values of more than 70 percent. Charging time A power bank needs to be charged regularly in order to be used effectively. Such a process should not take too much time. In the Powerbank Test 2018, we show you which Powerbanks are ready for use again quickly and which models are expected to have long waiting times.


As with any battery, the lifetime of cells in a power bank is limited. How long a device has to live is measured in charge cycles. In the Powerbank test, we carry out a stress test on the devices and can calculate an approximate value for the expected service life.

Many a power bank runs out of steam after just a few months, while Powerbank's benchmark competitors work reliably for years to come.


In addition to capacity, output power is also important in a power bank. Only if a certain amount of current is available, charging a device is also possible at a good pace. In the Powerbank test, we show you exactly which batteries are particularly convincing and in the best case even support the fast charging function of smartphone manufacturers.

Height and Weight

No Power Bank should necessarily be larger or heavier than necessary. If a device is too clunky, this is the portability in the way. In the test, of course, we distinguish between individual models.

A Power Bank with 20,000 mAh can’t be as small and light as a device with only 2,600 mAh, of course. However, a power bank should have a responsive and practical form factor relative to its performance.


A USB port on a power bank quickly gives the feeling that it can charge any device. This is also true of the best power banks, but by no means all. Especially with Apple smartphones, there are always problems here, and some other devices require too high a voltage, which can’t be spent by some power bank. In the Powerbank test, we clarify in detail which devices you can operate in individual cases. In the best case, the charging of notebooks is possible.

Features and functions

Many Power Banks provide other functions besides their main purposes, such as a flashlight or a charge indicator. In the test, we show if such or other features work as intended and if they make sense at all. In no way should an extra feature stand in the way of the main function, such as unnecessarily consuming a lot of energy from the built-in battery.


A good power bank does not come alone but with matching cables and adapters that allow for immediate use. Also not unimportant is whether a power bank is already charged in its packaging. In the test, you can see which power bank you can buy in an emergency and use it immediately for charging on your smartphone or tablet.

What do I have to look for when buying a power bank?

A power bank should always fit exactly to your own personal requirements. This starts with the existing connections. If you only ever want to charge your smartphone with a power bank, you can easily access a simple model with only one USB port.

However, if the tablet is to be recharged while on the move and in doubt at the same time as the smartphone, a power bank needs several connections. It is also important to ensure that all connections can be used simultaneously. That's not always the case.

The capacity of a power bank is naturally an important factor when buying. How high this should depend on the devices that are to be charged. The manufacturer's information is unfortunately misleading. A power bank offers its stated capacity only on paper but never loses it. Sometimes not even half of it is connected to a connected device. It is therefore advisable to play it safe. For example, if you use a smartphone with a 2,600 mAh battery, you will at least access a power bank with 5,200 mAh. The double capacity ensures that at least one complete charge is possible.


In addition to capacity, the current strength also plays an important role when purchasing a power bank. This is given in amps and determines how fast a power bank can charge a device. Some devices only provide 0.5 amps, so charging smartphones or tablets with a large battery take forever. Power banks with 2 amps or more, on the other hand, also allow you to use a quick charge function when a suitable cable is used. This allows even high-end smartphones to fully charge in less than two hours.

Brief information on leading manufacturers

Due to the increasing popularity of power banks, more manufacturers than ever are in the market today. In the following, we would like to briefly introduce you to the most important ones.


Anker is said to have emerged in 2011 from some former Google employees. These dreamed of a mobile world in which the power supply is always ensured on the move. The same dream should be realized with the company Anker. Power banks are a cornerstone of the offer and they come in a huge variation. Anker is also considered a manufacturer with particularly high-quality standards and many innovative ideas. Although the devices are certainly not the cheapest, as our power bank test shows, the investment is worthwhile in many cases.


PNY is a household name in the field of PC hardware. Since 1985, the Americans produce various products, including graphics cards, memory cards, and USB sticks. But over the years, PNY has never been embarrassed to conquer new markets. So the company is trying today also with the power banks. The results are mixed; in addition to some recommendable power banks, there are also some flops of PNY. Which devices can set themselves apart, reveals our power bank test.


Whenever electronics are concerned, sooner or later the name Samsung will fall. This is no different with Powerbanks. The tech giant from South Korea has its finger in all areas of technology in the game and also some power banks on offer. Last but not least, the models impress with their appealing and high-quality design. But the interior can usually convince. As so often, Samsung manages to find a good compromise between price and performance. Looking for a new power bank is worth a look at the portfolio of Koreans in any case. Many Powerbank winners have come from that same house in the past.

The History of the Power Bank

The power bank in its current form has not had a long history behind it. Just 10 years ago, there were virtually no such devices. At that time, it was still common practice to be able to replace the battery with a mobile phone. If you needed more energy, you simply carried matching replacement batteries with you. However, as more and more manufacturers took an example on the iPhone and its non-removable battery, this was not an option anymore and it had to be an alternative.

Powerbanks have since become highly valued by users, as they can also help smartphones with a built-in battery on the jumps. A nice side effect is the versatility of the chargers. Today, nobody needs countless additional batteries for digital cameras, laptops and tablets. Instead, a sufficiently sized power bank is enough to charge all those devices when needed. Although the environmental balance is slightly worse than with classic replacement batteries, most users accept this. They also have little choice, because there is no indication that the trend towards non-replaceable batteries will decrease in the future.

For a long time, Powerbanks developed at a rather leisurely pace. The market shares rose only very slowly, the big breakthrough was coming. In the summer of 2016, however, there was a real boom. Suddenly Powerbanks sold in masses, the manufacturers came with the production hardly behind. The trigger for this was the phenomenon Pokemon Go. Millions of gamers discovered the game for themselves but quickly discovered that smartphone batteries only allowed a few hours of gaming. Powerbanks were exactly the right remedy for that. So it was ultimately a game that could help this technique to their final breakthrough. They are now among the most widely used accessories for smartphones. Unless a breakthrough in research for new batteries succeeds, it will not change that fast.

Facts about the Power Bank

Studies repeatedly show the relevance of power banks today. In one of the International Data Corporation from 2014, for example, shows that the battery life for most users is the most important purchase argument for a new smartphone. The power supply enjoys an even higher priority than the camera of a mobile phone, the performance or the design. Manufacturers can’t satisfy the demand for long maturities. Not to save costs or to boost the sale of accessories. The technology of modern lithium-ion batteries are simply no longer in the small smartphone cases.


A look at the trends on Google shows that interest in power banks continues to grow steadily. In the last five years alone, search queries have more than quadrupled and the trend is still rising. Over time, it also shows how closely the success of the power banks is related to the permanently installed batteries in smartphones. Since this trend has prevailed in the industry, the interest of users in power banks is on the rise.


The power banks themselves do not use new technology in any way. In the end, it is little more than a battery in a case. A rudimentary charging electronics is hardly worth mentioning.

What separates the power banks from other chargers, however, is the ease of use and versatility.


Which devices can I charge with a power bank?

In principle, all devices that can be charged via USB can be charged with a power bank. It is also irrelevant which type of USB port it is because there are suitable cables for every possibility. However, it is important for a device to support charging via USB. Although some tablets and notebooks have USB ports, they can’t be charged.


For the power banks themselves, current in amperes determines which devices can be charged. Almost all devices are suitable for charging smartphones, for tablets or notebooks but it needs currents of more than 1 amp. In case of doubt, you will find out quickly and easily which application individual models are suitable for in our Power Bank review.

My power bank is getting hot, is this normal?

Heating during loading or unloading is completely normal and generally not a cause for concern. Only if a power bank gets so hot that you literally burn your fingers when you touch it, this indicates a defect in the built-in battery. In such a case, the power bank should no longer be used, but replaced by the dealer or the manufacturer. However, when such a step is necessary varies from model to model. However, the intended operating temperatures in the manual provide a good guide. Very high-quality power banks get along with almost no noticeable warming. Which these are, we reveal in the test. 

Do power banks discharge in the unused state?

It is in the nature of rechargeable batteries that they discharge even when not in use. Therefore, a power bank should always be recharged just before use. Who leaves his device for months, otherwise could experience a nasty surprise.


How much power banks discharge in the unused state depends on the particular device in each individual case? Powerbank comparison winners can maintain their full capacity for weeks. Some cheap representatives, on the other hand, lose their air after a few days, even though no use was made. In the test, of course, we clarify which devices can convince in this discipline and which not.

Can I charge a power bank on a notebook?

Yes, the charging electronics of a power bank can cope with many different current intensities and charging is in principle possible on any USB port. Power banks are similar in this respect very modern smartphones, which also need not necessarily be refueled at a power outlet with electricity. However, the charging process on a notebook often takes a long time.

Especially power banks with more than 10,000 mAh can ever need a full day for a full charge. If possible, charging a power bank should, therefore, be done on a power supply.

What should be considered when transporting a power bank?

The devices are usually very stable and it does not need a special protective cover. However, the power banks should not be carried loose in large pockets. The excessive impact can lead to defects.

This not only damages the technology, but can also be dangerous for the user. Damaged batteries can catch fire or in extreme cases even explode. Although this is very rare, nevertheless, a degree of caution during transport is appropriate.

Another important issue during transport is the temperatures. Power banks are designed to operate in very specific conditions. Most manufacturers specify temperatures of -20 ° C to 60 ° C for operation. These values can also be quite different. Users should take care not to exceed or fall short of the values given in the manual. This protects the device itself and ensures that in case of doubt, the warranty does not expire.



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