What Kind Of Powerbank You Should Get And Why!

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Are you confused about amps, volts and watts, and what does mAh really mean? We will tell you what you need to know (and what you don't) about buying a powerbank. A powerbank can be a lifesaver when you are far away from an electrical outlet. Even if you use power saving settings on your phone, it may not last all day. Powerbanks are happy to charge your phone up to several times, and your tablet too. Still, it can be difficult to know what to look for when buying powerbanks. How do you know if a powerbank manages to charge your phone and how fast will it charge? And what does mAh mean?

Anker is arguably the best known and most popular powerbank brand in the US, but EasyAcc, Omars and RAVPower are also great alternatives and we are including our recommended powerbanks in this article.

We were not financially compensated for this post and the samples were provided to us for review purposes. The opinions are completely our own based on our experience with the products.

Check the specifications

Fortunately, electric power is governed by math, which allows you to find out most things through reading the specifications. This does not mean that theory and reality always match. There is always energy loss when it comes to transmitting and transferring power, so you always end up with less useful power in practice than in theory. You can also never be sure that less serious manufacturers are not simply lying about the specifications.


Perhaps the most important specification of a powerbank is how much power it has capacity to store. This is usually stated in mAh (Milli Ampere Hours). A small powerbank will usually have 5000 mAh or less, a medium powerbank can go up to 12,000 mAh, while a large powerbank ranges from 12,000 to 36,000 mAh. 36,000 mAh is also the max capacity allowed in the cabin while flying.

It is also convenient that the capacity is stated in the same way as the batteries in mobiles and tablets. For example, the Samsung Galaxy S10+ has a battery with a capacity of 4100 mAh. If you have a powerbank with a capacity of 10000 mAh, that means that you should theoretically be able to fully charge the S10+ about 2.5 times (10000/4100 = 2.4). In practice, the figure will be lower. Most mobile phones have a capacity of 3000 - 4000 mAh, while tablets usually range from 5000 - 10,000 mAh.

In real use the typical capacity and power you can get from a powerbank will be 60-70% of its rated storage, as there are always loss of electricity (as heat) both when the powerbank discharges and the receiving device charges.


It is not only how much electricity the battery can store that plays a role, but also how quickly it can deliver this power.
Inexpensive powerbanks will typically have an output port rated at 1A, (1000 mA). If you have a phone with a battery capacity of 2000 mAh then that means your phone will use approx. 2 hours to fully charge via a 1A port.

However, if you have a 2A port on the powerbank, the same phone can be charged within approx. 1 hour. This is purely theoretical, as a number of factors will play a role in charging time. For example, some batteries will charge more slowly at the beginning and end of the charging cycle to protect the battery. Older batteries may also take longer to recharge.

Last, but not least, this also depends on if the mobile phone supports a 2A input. If it does not support it, the phone can enter a safety mode and only charge with 0.5A, or refuse to charge at all. The cheapest powerbanks will often only come with a 1A port, while more expensive powerbanks will offer two ports, one 1A and one 2A (or 2.1A or even 2.4A).
If you plan to use the powerbank with your tablet, a 2A port will probably be the best choice.

Some powerbanks also offer ports with QuickCharge(QC) or Power Delivery(PD) through USB-C ports for compatible devices. These can charge much faster if paired with compatible devices.


If you are only planning to use a powerbank with your mobile or tablet, you usually do not have to think about volt (voltage). Most powerbanks will work with most devices as long as the charging cable can be plugged into a USB port.

On the other hand, if you want a powerbank that you can use for other things, such as charging your laptop, then you need to go for a little more expensive powerbank.

Additional Features

It is very convenient if the emergency charger has some indicator of how much power is left on it. Most powerbanks have a LED scale that tells you how much charge is left. The slightly more expensive chargers also have a button that you can press to know how much power is left on the battery, without having to plug anything into it.

It is also popular to have a built-in flashlight. An LED bulb is power-efficient, so you don't have to use very much of the battery capacity to use the charger as a flashlight as well.

Solar chargers are another popular feature. This will increase the price of the charger slightly as solar cells are not inexpensive.

Other considerations

Exactly what type of battery is in the powerbank is not always important. Most use LiPo or Li-Ion batteries. The latter is most common as these have the best capacity in terms of size. Some less expensive powerbank still use LiPo batteries. It doesn't necessarily make them any worse, but it may make them larger.

Size and shape can also be very important, and higher capacity powerbanks are typically larger.

Also be aware of buying powerbanks from unknown brands as their performance does not always match their stated specifications and cheap parts can also be a fire hazard

The Gist

► If you just need emergency power for a phone to make it through a regular day, then get a small convenient 3000-5000 mAh powerbank, preferably with a 2A output port.
► If you are taking the family to an amusement park or to the beach for the day and several phones and a tablet needs topping of, then get a skinny 10,000 mAh powerbank with a short charging cable you can hold behind the phone while charging and using it at the same time.
► If you are going camping or will be off grid several days consider a 36,000 mAh powerbank. These large powerbanks also typically comes with faster charging alternatives like Power Delivery that is becoming a standard for charging laptops.
► Last but not least, buy a powerbank from a well-known brand.

Last Updated on 9/5/2019

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