Pass through Charhing-Power bank buying guide

How to buy the best power bank for your smartphone: 13 things to consider 5

So you have finally decided to buy power bank! Obviously you would long for buying best power bank available for your smartphone. In addition to that you are too much perplexed even after going through some other power bank buying guide, along with the vast availability of the power banks in the popular e-commerce sites and feeling helpless rather confused which one to choose, of what capacity and even bigger question from where. What else it could be after all when you have landed to this page! Anyway, if you are in such a condition then just don’t feel low as too many are there just alike you (even I had a similar feeling while going for my first one :p ). This exhaustive, epic guide on how to buy power bank, would make you smoothly zero in on the exact portable battery pack that you need.


Power bank buying guide


If you believe me, there is nothing tricky or something like you must be very gadgetaholic to find the best rather most suitable external battery pack. You are just required to keep some basic things in the mind while making the selection.

But before we start our power bank buying guide, let’s get to know what power banks are and how they function.

Power bank: What is it?What is a Power bank? How to buy power bank

To put it simply, portable power bank is a collection of cells controlled and guided by a micro-controller enabled PCB with sophisticated casing to store energy and let you use that power afterwards to charge your devices like smartphones, tablets On-The-Go without any hassle.

Kinds of power banks:

Generally, the most available portable chargers are universal ones with USB output and micro-USB input ports. Though there exists some newer kind that is solar power bank, which in generally as the name suggests, though primarily charged by the solar power, commonly comes with a provision to charge with normal USB wired charger as well.


Waaree Solar Power bank 10000 mAh

 Waaree Solar Power bank 10000 mAh


Types of the cells:

There exist two major types of the cells used in the power banks, Lithium-ion (mostly ‘18650’ type cell having abbreviation Li-ion) and other one is Lithium-Polymer (also called Li-Poly). Li-ion ones are cheaper than that of the Li-Poly and thus are used extensively but Li-poly do have more charge bearing capability than Li-ion per unit weight, it is also safer. You will find a detailed section about these later in this guide on how to buy power bank.


How does power bank work? How does power bank works? power bank buying guide

Functioning of power bank is pretty simple, as you can plug in the portable charger through its USB cable at your convenient time and place to get it charged and when done, you can carry it along with you so that you can use it when you actually need the ‘power’ to charge your smartphone but cannot find a good old plug point hanging out of the wall, readily available nearby.

Okay, Let’s now start with the points that one must be having in mind while buying best power banks, which would be suitable and thus perfect for your smartphone or tablet.

1. Estimating the power consumption

 Capacity of Power banks- How to buy power bank


Capacity is the primary attribute rather identity for power banks, as they are often known by it. You must be hearing and seeing the various ranges like 2600mAh, 5200 mAh, 10400 mAh and so on. These signifies the charge holding capability of the power banks. You must be able to spot the appropriate capability level which would be sufficient as per your need. But then comes how one would be able to determine the need? Don’t worry, let’s move one by one.


Capacity of the power bank is measured in mAh, the same unit as that of the battery of your very smartphone. Again why it would not be so, after all it is a collection of battery in a sophisticated manner! Anyway, to be a little technical, mAh is nothing but milli-Ampere per hour. It determines the amount of power that flow over time and thus manifests the robustness of a powerbank. More mAh signifies greater energy possessing capability.

What is mAh of a power bank


So, the common thought about the portable charger capacity goes like why would one go for small capacity power banks then? But there are absolutely rational reasons as well for choosing the lower capacity ones as with the capacity of the power banks, the size of the power bank also get increases in general and so does the price.


Price increases with the size of the power bank- buying best power bank

Further, to be objective, portable charger is something that one is to use in emergencies or contingencies. Obviously you are not going charge your phone with it at the home for sure, right? (Unless it is power cut!) So why should we think about huge ones?  Hence we have reasons for going both way, either for small capacity ones or for big-capacity ones. And the answer would be decided by the individual need of the consumption.

Now let’s concentrate on the need. So the need or power usage can be measured as the number of times you would be willing to get your smartphone charged fully with one full charge of the power bank. We do have a little formula for that but before that let’s get accustomed with a few terms quickly:


How much power of a powerbank do I need? Power bank buying guide


You can hear a lot of allegation that power banks do not supply charges as they claim. It is ideally thought that a battery pack with certain capacity would be able to charge a smartphone with same capacity battery fully once but that is not the case in reality as being an intermediate device of transforming energy, there are some evident losses of power and thus no power bank is capable of converting 100% of its own capacity in actuality. Here, we can have a mathematical formula about efficiency here:


Efficiency of a power bank- How to buy power bank

 Device Depletion (Health of your mobile battery):

In layman’s term, it is a measurement in percentage telling about the health and condition of smartphone’s battery. Though for sure it might be difficult to find out this figure for your smartphone, but in general when we would be going to find our need of power usage, this factor matters.

Now you can look at our master formula which determines the number of times a certain power bank can fully charge your smartphone.


formula for power bank capacity calculaion - How to buy power bank


Here, if we go by some example, let’s consider a power bank with capacity 6000mAh and having 80% efficiency and your smartphone’s device depletion also being 80 % with a battery capacity of 1500 mAh, you can get your mobile approximately 2.5 times charged with it.


Formula for calculating the number of times a power bank charges a smartphone- power bank buying guide


With the help of this formula, sticking to a required charging frequency, you can arrive to some definite conclusion about what capacity can fulfill your need.

In addition to this, the capacity calculation may get also affected if you plan to charge more than one device with your power bank may be simultaneously with multiple output ports or one after another, sequentially with a single port.  In both the cases, the above formula based calculation can be carried out for each devices and the resultant sum would be the requirement.


Also Read: The Best Power Banks of 2016


2.  Input ampere

Oneplus 10000 mAh power bank white


Oneplus 10000 mAh power bank

As per Hardwarezone, they mentioned in their guide on how to buy power bank, “It’s easy to persuade yourself to buy a large-capacity battery pack. But one tends to forget that the higher the capacity, the longer it takes to recharge”. In fact, this is among the many factors which restrict one to go for a big capacity power bank.

The input ampere rating of a power bank is something that actually determines how long it would take to get charged and is most often found to be either 5V-2A DC or 5v-1A DC. This measurement is specified for every power bank so you can just get to know it without much hassle. To simplify the meaning of these, the one with rating input ampere 5V-2A DC would get charged twice as fast as compared to the one with input ampere rating 5V-1A DC. For sure you would never be seeking a lazy self-charging powerbank, so 5V-2A rated power banks will be more preferable always (But to get the optimum result, you must also use 2A wall charger to charge the power bank).

Ambrane-p-1000-10400 mAh


A simple real instance can be cited here. The PNY b-740 10400 mAh capacity power bank with 5V-2.1A DC input rating gets charged fully by 6 hours at most whereas the 5V-1A DC rated Ambrane P-1000 10400 mAh with same capacity would take almost 11 hours to get replenished in an average.






PNY b740 10400 mAh Power bank- How to buy power bank

3.  Output Ampere

Now in this guide on how to buy power bank, we are concerned with the charging time of the smartphone rather than the portable charger, in other words the current drawing capacity of your phone. In most of the cases it is found the old phones do have a specification of 1A but the newer smartphones and tablets, particularly which do follow the Qualcomm’s Quick Charge 2.0 standard are in contrary do have a rating of 2.1A. You can get this rating from the original charger for your device or the data sheet.


adata pv110 power bank- Buying best power bank         ADATA PV110

You can find the Adata PV110 battery pack above with having dual USB output ports each with 1A and 2.1 A rating respectively.

One common concern is noteworthy as many are found to get apprehensive, thinking if they charge their smartphone with some power bank having greater output rate than the input rating of their smartphone, would that be harming their devices? The answer you will get in this power bank buying guide is exactly no as the smartphone would just draw its required power from the source and let itself get charged, causing no damage to itself.

As far as the output ampere rating is concerned of the power banks, you would get your devices charged almost twice faster with the 5V-2.1A output port than 5V-1A ports. Nowadays most of the battery packs with capacity greater than 10000 mAh comes with multiple ports and among them at least one happens to be 2.1 A certainly. And thus for the small capacity powerbanks with single output ports, it is advisable to go for 2.1 A one.

Moreover if you are too much concerned about the safety of your phone and ready to pull up your budget on account of that then Astro pro series power banks are just made for you. These have some really smart feature of smart charging where the usb output ports provides upto 5V-3A depending upon the current drawing capacity of the device you are attaching to it.

Anker-Astro-Pro2-ports Smart charging

Anker Astro Pro2 Power Bank

4.  Number of USB slots


meme brings power bank forgets to bring wire- buying best power bank


Never mind if you see someone being in his situation because he is not the only one on the earth forgetting to bring the wire while carrying the power bank. And being it such a common phenomenon, a number of manufacturers have come up with built in charging wire for the portable chargers like Amekette Fuel Card Portable Power Bank, though I personally am in love with its excellent design otherwise.

Amkette- fuel-card-portable-power-bank-2500-mah-

Amekette Fuelcard Power Bank


The limitation of these built in wire portable chargers is that they are rare than the open port ones and particularly if you do have multiple devices to charge simultaneously then you are going to find at most two wired power banks, not more than that like Atam C-26 8800 mAh portable charger.


Atam C-26 8800 mAh power bank- power bank buying guide

Atam C-26 Power Bank

On the other hand, if you really need of more than two USB outputs or you just do not feel to go for the wired ones then there are a lot of options available for you starting from easy available 1 USB port till 5 USB slots. But the greater is the number of the ports, the higher is usually the capacity of the power bank and so is the price.

Xiomi Mi 10400 mAh Power bank

 Mi 10400 power bank with 1 USB port

Intex IT-PB 10k 10000 mAh Power bank

Intex IT-PB 10k 10000 mAh power bank with 2 USB ports

Adcom Ap3+ 12400 mAh power bank - How to buy power banks

Adcom AP3+ 12400 mAh power bank with 3 USB ports

While going for the higher number of ports, one must make sure the total amount of current allotted while simultaneous charging. It might be like if the two USB ports are there each rated as 5V-2A, the battery pack allots 2A current to the ports when charging a single device but at the time of simultaneous charring, the powerbank allots 1.5A to each port summing up, making a provision of 3A altogether or it might be that it is capable of discharging 4A current by splitting into 2A for each port.


4 USB port Power Bank Easyacc 12000 mAh

Easyacc 12000 mAh power bank with 4 USB ports

5 USB port Power bank Photive 12000 mAh- Power bank buying guide

Photive 12000 mAh power bank with 5 USB ports


5.  Portability

A power bank should be easy to carry along with, this is one of the basic criteria and it gets betrayed when you would be heading towards big capacity battery packs, mostly the power banks with capacity more than 10400 mAh with a few exceptions turn up with a dimension of at least 8 cm*4 cm and weighing not less than 350 gms.

Portability of Powerbanks Matter- Power bank Buying guide

Which becomes a bit inconvenient to keep in pocket though still can be shoved inside your
backpack. But it is all a compromise that you are required to make with higher capacity and thus size because a huge capacity powerbank is always everyone would prefer but again being bulky, it would defeat the purpose of the portability and convenience.




6.  Price

Though a specific relationship could not be set up being particular among the capacity and the price of the power banks, still the following is a try in this power bank buying guide to depict the present trend of the market.

Capacity of Power bank Average Price of Power bank
Less than 2600 mAh 350 INR
2600 to 5200 mAh  500 INR
5200 mAh to 8000 mAh 700 INR
8000 mAh to 10400 mAh 950 INR
Greater than 10400 mAh 1200 INR

Obviously price does not depend solely upon the capacity of the power banks, yet it primarily depends and with capacity, price invariably increases.

7.  Brand and Reputation

Trusted Brand for Smartphone Power banks- buying best power bank for smartphone

 Buying any portable charger from best brands does not entails it would be perfect for you but buying best power bank for your smartphone presupposes that it should be from the best brands. Branded battery packs are the ones you should always prefer and this point is much crucial in this guide on how to buy power bank, as you can see numerous companies popping out from nowhere in e-commerce sites and surprisingly they just do sell nothing but only portable chargers like lappymaster, Batman, Champion, Syska, Wayona, Urban Monkey and so on, they are truly endless. The bottom line remains the same, branded external batteries might cost a bit more but trusted brands are always advisable to count on.


8.  From where to buy

Trusted Ecommerce Sites: Flipkart, Snapdeals, Amazon and Paytm - How to buy power bank


This is the point which you are going to miss for sure in any other power bank buying guide but ironically it is important as sellers matter. As far as battery pack is concerned you can trust the sellers from Flipkart, Amazon, Snapdeals, Infibeam, Paytm, Ebay & Shopclues (selected cases) if you are going for online purchase and avoid like a plague askmebazaar, naaptol or any other less reputed sites as there is a high chance that you would be getting cheated as they sell fake products without any shame. Here is one instance of Shopclues selling fake portable chargers.

If you are still finding it difficult about which online site would be better to go for, this post on where from to buy power banks online might be a good help.

[Update: Shopclues used to sell a lot of fake power banks not only for Mi, but also for other brands as well somedays back, but they have recently stopped that nasty practice and are in the try to be honest with their products now.]



9.  Warranty details

Warranty of power banks- Power bank buying guide

Most power banks, in fact almost all the branded power banks comes today with a warranty period of 1 year (though some comes with 5 months as well and the fake ones comes with no warranty at all, :p) and the same can be found at the product description.

In association to warranty, this guide on how to buy power bank would advise you to just make sure that the post purchase service is tangible from the corresponding brand.



10.  Battery

Lithium-ion vs Lithium-polymer Power banks- Power bank buying guide

While on the verge of buying best power bank, you already know that there are two types of battery cells comprising power banks likely lithium-ion and lithium polymer. Choosing between these two depends again on the nature of your usage like if you are going to use too often your power bank, would not mind about the weight and have a lower budget then lithium-ion is better. Again if you are going to use the charger not too frequently and you prefer safety over money then Lithium-polymer would be the right choice. [Here comes a very helpful article from powerseedus, besides this how to buy power bank guide on why and when a battery pack can explode]. Obviously I have no intention to frighten you, but it is always better to be aware of the safe usages.



11.  Quality and Safety:

Safety protections of Power banks- Power bank buying guide

Quality and safety are the non avoidable points in any power bank buying guide and are also important to look upon for buying best power bank. Portable charger comprises of the battery cells and you should be scrupulous and concerned with it’s safety. To do that ensure the following protections in your ‘would be’ power bank:

What is Short-Circuit Protection?

Shortcircuit protections in powerbanks

This protection enables to protect your power bank from getting damaged when the output and input of the battery pack is shorted. Generally such a shorting would make the power bank try to charge itself and end up discharging quickly and generating heat. But while your powerbank have such a short-circuit protection, you can remain tension free as detecting a short circuit, your external battery pack would cease to discharge.

What is over Voltage Protection?

With over voltage protection, you can get your power bank discontinued from getting charged if the voltage level of the charge source goes up the threshold.

What is over current protection?

In the same way if the charging source of the power bank provides current more than the required, the battery pack would cease to get charged with over current protection.

How to buy the perfect power bank for your smartphone- How to buy power bank


What is over charge protection?

Overcharge Protection in power banks- Power Bank Buying Guide

If you have over charge protection in your portable charger, then the power bank would not get charged even if it is plugged in, if it detects its own power voltage getting over a certain safe level.



What is over discharge protection?

Again with over discharge protection, the power bank would cease to discharge detecting its power level in terms of voltage getting down below a threshold limit.


Overheating protections in power banks- buying best power bankWhat is overheat protection?

Overheat protection in your power bank would make the battery pack refrain from discharging or getting charged if it finds the temperature of the battery pack has gone beyond a predefined boundary. Again for the same reason many apprehend about the explosion of power banks which is not completely baseless. Though Lithium-ion portable chargers are not going to explode until you mishandle it, yet if you are too much concerned here, then I recommend in this power bank buying guide that Lithium-Polymer powerbanks would be a good choice being less prone to explode.

12.  Pass Through Charging

Now what does that mean? Before clearing it further let me ask you whether it had ever come to your mind or even if you have experimented by trying to charge your power bank and then in turn trying to charge your smartphone at the same time by it? It may sound weird, but time comes when both of your power bank and smart phone goes off, and you need to get them charged fast and again you have only one charging option (say a single wall charger). In such a case power banks with not having pass through charging feature would make your face the trouble.


Pass through Charhing-Power bank buying guide


So precisely pass through charging makes you charge your device from the power bank while the power bank itself is getting charged. Most of the external battery packs lack this feature, thus it is better to go for the ones coupled with this trait if you face such situations often.

13.  Shape and Design

Slick and slim Power banks- How to buy power bank


Isn’t it cool? Sure it is, you would be possibly dying to get one of such sleek power bank and show it off in your circle. But unfortunately such sleek, compact handy powerbanks in most of the cases are not actually functioning ones unless you have already spent more than 2k. So if you see while going to buy the best power bank, some 10400 mAh power bank having a superb slim design and compact size at 500 INR, be sure that is either having capacity at most 4000 mAh (might be even less) or it is only for show.


Hence to sum up, the bottom line of this guide on how to buy power bank while buying best power bank goes like this:

  • Don’t go for fake ‘Best’ ones
  • Estimate what capacity power bank you need
  • Mind the input rate
  • Pick higher o/p rated power banks
  • Calculate number of ports you require
  • Fix up a budget not too low
  • Go for trusted, reputed brands
  • Buy from trustworthy sellers
  • Check the warranty details
  • Find the quality of battery
  • Ensure standard safety protections
  • Consider pass through charging, if required
  • Prevent getting persuaded by the look and price of power banks

In addition to the above list, hopefully you would find this visual infographic from powerbanky useful as well which would additionally sum up pictorially the points.


powersolvemobile, verified9jablog, cablechick, timesofindia, hardwarezone, qualcomm, smartpowerbank, ebay, powerbankreview, sproutinc, mobilecon, techgarage, kickassgadgets, bestpowerbanksformobiles, spring, cellz, rediff, showyourflipside, geckoandfly, mouthshut, powerseedus,indiegogo and wikipedia.


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About Aditya Chowdhury

Aditya is a tech blogger and an expert gadget reviewer. Here at Powerbanky, you will get all the latest and top portable chargers AKA power banks being throughly reviewed by him.

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5 thoughts on “How to buy the best power bank for your smartphone: 13 things to consider

  • Radhika

    Power banks are not needed anymore to charge a smartphone as they take lot of time to charge. One can use FLI Charge, which can charge your smartphone as fast as plugging into an outlet. In other words it can charge instantly by utilizing conduction charging method. The fastest charger on the marketplace and also charge multiple devices(6+) at a time. Use AC Outlet to charge FLI Charge itself.