Powerbank20, a website that tests external batteries for you

That external batteriesalso called power banks » has become the ideal accessory to recharge our devices anytime, anywhere: walks, country excursions, metro, beach…

However, as with phones or laptops, a very large variety of brands and models of external batteries can be found on the market, and this great diversity can pose a problem for the buyer:

What are the best models? Which power bank should I use for my phone?

To help answer these questions, we offer you the website for PowerBank20an independent project responsible for testing hundreds of external batteries available on Amazon to offer its readers an analysis centered on more objective criteria: energy efficiency, power, charging time, etc.

This way we can find a location on its main page of the month’s 20 best external batteriesincluding models that have already been tested and passed their recommendation criteria, as well as those that are being analyzed but due to their characteristics are considered worth recommending to their readers (if, after analyzing them, they do not live up to expectations, they removed from the ranking list).

Moreover, the results of PowerBank20 analyzes are free to access and we can find them published on their website, allowing more technical or curious users to know in depth the results of each external battery analyzed.

What is analyzed on an external battery?

For every external battery purchased on Amazon, the Powerbank20 team subjects it to 2 main tests:

Charge/discharge energy efficiency test:

For this test, the external battery is completely discharged using an electronic load of a certain power, depending on the type of discharge (or unit charge) allowed by the model: standard (10W), fast Quick Charge 3.0 (14W) or Power delivery (14W, 24W or 40W).

When the external battery is discharged, they check the energy it was able to supply and thus determine its energy efficiency : energy delivered / energy stored.

For example, external batteries with a capacity of 20,000 mAh (or 20 Ah) have an internal battery that stores an energy of 74 watt-hours (Wh), the result of multiplying the capacity and the nominal voltage of the battery, usually 3.7 volts :

Stored energy = 20Ah x 3.7V = 74Wh

In the following image we can see several 20000 mAh models analyzed by PowerBank20 where it is shown what the supplied energy and its energy yield are for a standard derivation (without QC 3.0 and/or PD technology):

An external battery is considered quality when its energy efficiency is equal to or greater than 85% during discharge.

They also measure charging time and energy efficiencyi.e. the amount of energy that must be supplied to the external battery to fully recharge:

Power Bank Standard Discharge Energy Yield Graph

It is interesting to see that there are 20000 mAh external batteries with fast charging technology Power supply on their entry port which is able to recharge in less than 6 hours (approx) compared to other models without fast charging which need a duration of 10 to 20 hours to recharge.

20000 mah Power Bank recharge time

Power test

An external battery charges devices faster if it is able to provide the power that each device requires.

The specifications of a power bank generally indicate the current that each of its USB output ports can deliver, for example:

Features USB ports external battery

If the USB output port on a power bank shows 5V/3A, it means that the maximum power it can output is 15W (5V x 3A).

In this test, the team is off PowerBank20 controlled the maximum individual effect that each of the USB output ports on a power bank can supply and maximum total power from all its ports at the same time.

External battery current test

I want to buy an external battery: where do I start?

PowerBank20 recommend that we ask ourselves first what kind of devices it must be charged with an external battery and their frequency of use ?

We must never forget that electronic devices, in this case external batteries, must adapt to our usage needs and not the other way around.

For example, if you need to use a power bank daily for your phone because its battery runs out at the end of the day or ends “very low”, then a model 10000mAh capacity will be more than enough. In addition, its weight and dimensions are much more comfortable to carry in a trouser pocket, bag or backpack without taking up too much space.

On the contrary, if you want one external battery to take with you on a trip and you need enough energy to charge your phone several times or also charge other devices (tablet, earphones, camera, e-book, friends’ phone…), it is better to turn to a 20000 mAh external battery with 2 or 3 USB portsideal for its size and weight.

External batteries 10000mah and 20000mah

Once you know the use you will primarily make with the external battery, look for it its technology incorporated and of course on your budget.

In general, it is recommended that the power bank integrates the new port USB Type-C (reversible) and fast charging technology Quick Charge 3.0 (QC) and or Power delivery (PD) at the input port (external battery charging) as well as at the output port (device charging).

On large capacity models (20,000mAh or more), it is also almost imperative that the input port has fast charging* to avoid long hours of waiting while fully charged.

* Of course, it will also be necessary to use a charger compatible with fast charging of the external battery (QC 3.0 and/or PD) if you want to take advantage of this technology.

Obviously, buying the latest fashion always comes at a higher price, and at this point, you should ask yourself if owning a state-of-the-art power bank is really worth it (with the appropriate charger) if your phone doesn’t have fast charging or a USB C port and you don’t plan to change it anytime soon.

I have a laptop: can I use an external battery?

PowerBank20 recently published this guide where they explain in detail the options available to charge any laptop and the types of power banks that can be used depending on their charging port and the power it can provide.

External laptop battery

Thanks to the tests carried out in this guide, it has been confirmed that it is a completely valid and recommended product, as long as you use the right model, taking into account excitement where your laptop charges from Powerful power bank can deliver and the usual type of task you do, for example playing video games, will consume more energy than surfing the internet.

Additionally, an external laptop battery can be a very useful option for people who cannot replace their computer’s dead battery and must always use it plugged in.

In short: which external battery should I buy in 2022?

Given the current behavior of the market, it is best, rather than staying focused on a single brand, to know what characteristics can make a specific external battery more or less interesting according to each person’s needs, so we will focus on:

  • Capacity of 10000 mAh or 20000 mAh
  • Presence of the USB-C port
  • Input/output ports with PD and/or QC 3.0 fast charging (at least one)
  • Interesting options: solar panel, compass, wireless charging point, flashlight…

In addition to Xiaomiif you want to know brands that stand out in the sector, we recommend that you take a look at the external batteries from Anker, Charmast, Baseus or Ugreen.

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