External batteries or power banks have become the ideal accessory to recharge our devices where and when we want: trips, field trips, subways, beaches … However, as with mobile phones or laptops, there is a great variety of brands and models of power banks on the market and this may pose a problem for the buyer: What models are of better quality? What power bank do I need for my mobile?
To try to answer these questions, we found the PowerBank20 website, an independent project that is in charge of testing hundreds of power banks available on Amazon in order to offer its readers an analysis focused on more objective criteria: energy efficiency, power, loading time…
In this way, we can find on its main page a ranking with the 20 best external batteries of the month , including both models that have already been tested and that have passed their recommendation criteria, as well as those that are in the process of being analyzed but that, Due to their characteristics, they are considered interesting to recommend to their readers (if after analyzing them they do not meet expectations, they are removed from the ranking).
As a curious fact, the results of the PowerBank20 analyzes are freely accessible and we can find them published on its website, allowing more technical or curious users to thoroughly know the results of each analyzed power bank.
What to analyze in a power bank?
For each power bank purchased from Amazon, the PowerBank20 team submits it to 2 main tests:
1. Energy efficiency test in recharge / discharge:
In this test, the power bank is completely discharged using an electronic charge at a certain power, depending on the type of discharge (or device charge) that the model allows: standard (10W), fast Quick Charge 3.0 (14W) or Power Delivery ( 14W, 24W or 40W).
Once the power bank is discharged, they check the energy it has been able to supply and with it, its energy efficiency: supplied energy / stored energy.
For example, 20,000 mAh (or 20 Ah) capacity power banks 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, normally 3, 7 volts:
Stored energy = 20 Ah x 3.7V = 74 Wh
In the following image we can see several models of 20,000 mAh analyzed by PowerBank20 where it is shown what is the energy supplied and its energy efficiency for a standard discharge (without QC 3.0 and / or PD technology). Keep in mind that a power bank is considered quality if it has an energy efficiency in discharge equal to or greater than 85%:
Likewise, they also measure the time and energy efficiency of recharging , that is, the amount of energy that must be supplied to the power bank to fully recharge:
It is interesting to see how there are 20000 mAh power banks with Power Delivery quick recharge technology at their input port that are capable of recharging in less than 6 hours (approximately) compared to other models without rapid recharging where their charging time would imply between 10 and 20 hours.
2. Power test
A power bank will charge devices faster if it is able to supply the power demanded for each device.
The specifications of a power bank usually indicate the power that each of its USB output ports can supply, for example:
If the USB output port of a power bank indicates 5V / 3A, it means that the maximum power it can supply would be 15W (5V x 3A).
In this test, the PowerBank20 team checks the maximum individual power that each of the USB output ports of a power bank can supply and the maximum total power of all its ports at the same time.
I want to buy a power bank: where do I start looking?
PowerBank20 recommends that we first ask ourselves what type of devices are you going to charge with an external battery and with what frequency of use ?
We must never forget that electronic devices, in this case external batteries, must adjust to our needs of use, instead of us to them .
For example, if you need an external battery to use on your mobile every day because its battery runs out or arrives “very fair” at the end of the day, then a model with 10,000 mAh of capacity would be more than enough, in addition, for its weight and dimensions is much more comfortable to carry in a pants pocket, bag or backpack without taking up much space.
On the contrary, if you want a power bank to eventually take you on trips and you need it to have enough energy to charge your mobile several times or also to charge other gadgets (tablet, headphones, camera, ebook, friend’s mobile …), consider that a 20000 mAh power bank with 2 or 3 USB ports is ideal for its size and weight.
Once you are clear about the main use of the power bank, you should think about the technology it incorporates and your budget :
In general, it is recommended that the power bank incorporates the new USB Type-C port (reversible) and Quick Charge 3.0 and / or Power Delivery (PD) fast charging technology both in the input port (recharging the power bank) as in the output port (device charging).
Also, on large capacity models (20000mAh or higher) it is almost imperative that the input port have fast charge * to avoid long hours of waiting during its full recharge.
* Of course, it will also be necessary to use a charger compatible with fast charging of the power bank (QC 3.0 and / or PD) if you want to take advantage of this technology.
Obviously, buying the latest fashion always has a higher price and, at this point, you should think about whether it is worth having a state-of-the-art power bank (along with the appropriate charger) if your mobile does not have fast charging or a USB C port and you have no intention of renewing it.
I have a laptop: can I use a power bank?
Recently in PowerBank20 they published this guide where they explain exhaustively the options that exist to charge any laptop and the types of power banks that can be used according to their charging port and the power it can supply.
Thanks to the tests carried out in this guide, it was confirmed that it is a totally valid and recommended product, as long as you know how to choose the correct model taking into account the voltage at which your laptop charges, the power that the power bank can supply and the The usual type of task you do, for example, is not the same as playing video games (it consumes more energy) than surfing the internet.
Also, a laptop power bank can be a very useful option for those people who cannot replace the dead battery in their laptop and always have to use it plugged into the mains.
In short: what power bank to buy in 2020?
Taking into account the current market behavior, the smartest thing, rather than getting stuck in a single brand, is knowing what characteristics can make a specific power bank more or less interesting according to the needs of each person, so we would pay attention to:
- 10,000 mAh or 20,000 mAh capacity
- Presence of the USB-C port
- I / O ports with fast charge PD and / or QC 3.0 (at least one)
- Interesting extras: solar panel, compass, wireless charging point, flashlight …
In addition to Xiaomi , if you want to meet brands that stand out in the sector, we recommend you take a look at the external batteries from Anker , Omars , Poweradd , RAVPower or Ugreen .
