The main attribute associated to a power bank is its capacity.  This capacity is measured in milli Ampere Houri.e. mAH. You can’t exactly calculate how many times a specific power bank can charge your device, but the rule of thumb is more mAH rating mean more capacity.

If you have a mobile phone with a 1500mAH battery, ideally a capacity of 1500mAH can fully charge it once.  And when you buy a portable power bank, make sure that it can charge the battery of a specific device. By this I mean  make sure its output voltage matches with the device you own, because if the output voltage of the charger is less than the device being charged, you will have problems… basically it won’t work.

Of course, the reverse is true, if you have a charge with a larger output voltage than your device, you should be able get several charges for your device.

Should you decide on buying a portable charger, keep your own usage in mind.  To meet huge charging needs of consumers, 8400mAh and 11200mAh, (and higher mAh) units are also available.  There are chargers that can charge almost any type of device, from all types of companies. This includes laptops, ipad, ipod, tablets, and mobile phones from Apple, Samsung and HTC. Sample Usage Guide…

• 1500mAh battery : mobile phone – 1 full charge.
• 5200mAh battery : mobile phone – 2 full charges. Tablet – approximately 50%.
• 10000mAh battery : mobile phone – 4 full charges. Tablet – at least 100% full charge.

Power banks are available for purchase in most countries at various prices and in varying sizes and specs.  Before buying one,  you should make sure that they are new products and not used merchandise.  Used cell phone battery chargers will be a waste of time and money as their life span is greatly diminished.

The life span of a power bank can also be greatly reduced if it is kept in adverse environmental conditions for a long period of time. There are portable chargers whose lifetime is reduced at temperatures more than 45 Celsius. However, at extreme temperatures such as over 70 Celsius there is a high probability that the battery will be completely damaged.

Most current power bank chargers have built in USB charging capability.  Some of the older models don’t have this feature.  They have a separate cable which one had to carry along with the device. This added to the number of things that could potentially go wrong in using the charger.

After you fully charge your power bank at home, it is a simple matter to connect the device to your cell phone with an adapter and your phone will start charging instantly.   The better quality power banks will come with a set of connectors for different device types, such as, Sony,  Apple, Samsung, etc.

Apart from battery strength, one other thing which can help you decide which power bank charger is best for you… is the price.  But you should not buy a portable power bank which either uses refurbished batteries or which doesn’t contain the basic features e.g. short circuit, over-charging protection.

One of the main reasons to buy a power bank is the portability factor. The ability to  charge your devices while on the move because you can simply take a charger with you, is a huge plus.

Be careful with the inexpensive ones with big capacity. Many times you get what you pay for, meaning they may not charge  your gadgets properly, or even worse, break down on you.

If you are looking to buy a external cell phone battery charger, we really recommend not going for the cheapest option. This is one of times where you do indeed get what you pay for. A mid-range to upper range price will be a great option with no sacrifice on quality.

Because of the large number of personal devices that we now have such as iPhones, iPads, Ardroids, smart phones, some cameras, GPS, MP4, IPods and Bluetooth to name a few, it’s practically a necessity to have one if you want to make sure that you never run out of battery power on your device. There is nothing more frustrating than running out of battery.

Before I bought Power Bank, during a long road trip, using Google Maps with my mobile phone, my car charger stopped working, so my cell phone battery died one hour through a 5 hour journey and I had to find my way without back home relying on stopping and asking people for directions multiple times. After this frustrating experience I went out and picked up a portable charger and use it all the time.