Have you ever been in a situation where you had an important call to make or a mail to reply to, but couldnt because your phone ran out of battery; were on a vacation, using your phone to get directions and click photos, but there was no juice left; were waiting at the airport to board a delayed flight, but your tablet died in the middle of the movie. If the answer to any of the questions above is yes then, then thinking about a buying a power bank is corollary. But if you are regularly on business trips or travel a lot or take frequent vacations, and you don't own a power bank, then my friend, you are living dangerously. See all 11 photos Anker Power Bank, charging three devices simultaneouslySource: amazon.com What is a power bank?Power bank is the device to prolong the usage duration of your electronic gadgets such as phones, tablets and iPods. Power bank can increase the usage duration from a few hours to several hours depending on your device and power bank. Power bank is basically a rechargeable external battery pack which can charge your device, while it itself gets depleted. See all 11 photos Uses of a power bankPower bank will be primarily used to charge your device when you are on the go with no other power source nearby. It can used to charge your phone while you are on vacation, so that you can continue clicking those awesome photos. Power bank can also be used to charge your GPS watch (provided you have right adapter) while you are trekking in a remote area. You can also use your power bank to keep your tablet charged, when you are sitting in a coffee shop, typing away the mystery novel you have always wanted to write. See all 11 photos Source: inspiritworld.com See all 11 photos How to decide which power bank to buy?For many of us finding a power bank perfect for our needs could be a byzantine process. But if you know what to look for in a power bank, you will [[http://Realize.net/|realize]] that it's not as complicated as you think it to be. I have compiled a series of question to help you decide on a specific power bank. You start by answering the first question, and by the time you reach the last question you will have made up your mind about the power bank you are going to buy. Remember, you cannot get the best at cheapest price. But if you are ready to make small compromises, you can get good deals fairly frugally. See all 11 photos What capacity power bank do bank i need?This is the first question you need to ask yourself. Power bank capacity is generally defined in term of mAh (milliampere-hour). Higher the mAh rating, more charge it can provide to your Device. Suppose, you have a mobile with a battery rated at 2300 mAh and you generally charge your battery once a day. So on a three day trip you will need to charge it two times, your requirement for power will be 2300 x 2 = 4600 mAh. It is always good if the power bank capacity is a little higher that your requirements. So, you should look for a power bank with [[http://browse.deviantart.com/?q=capacity|capacity]] of about 5200 mAh. You need to find out the battery capacity of your phone and tablet, and decide how are you going to use your Power Bank. Then you can calculate how much capacity you need. See all 11 photos Real capacity of a power bank is less than mentioned capacity. See all 11 photos What is the efficiency of power bank?Only in ideal conditions a power bank can transfer all of its energy to the device it is charging. In real life conditions, some of the energy is lost during transfer due to heating of device. Generally, good power banks have energy conversion efficiency of about 70% - 85%. It means that a [[http://www.itaddictedshop.com/|power bank]] of 10000mAh capacity with 80% efficiency will be able to provide only 8000mAh. So while deciding upon a power bank, energy conversion efficiency should also be accounted. A rule of thumb would be to use 1.25 as a multiplication factor. Therefore, if your requirements are 4600mAh, you should find a power bank rated around 4600 x 1.25 = 5200mAh. Mobile Battery Capacity Tablet Battery Capacity Number of charges required Actual required capacity of Power Bank Recommended Power Bank Capacity 2300 NA Mobile - Two, Tablet - NA 2300 x 2 = 4600 5200 2400 NA Mobile - Three, Tablet - NA 2400 x 3 = 7200 9000 2200 6700 Mobile - Three, Tablet - One 2200 x 3 + 6700 = 13300 16600 Use this table as a reference to calculate your power bank requirements.Capacity is in mAh. Recommended power capacity is calculated by considering 80% energy conversion efficiency. What is my budget?Next thing you need to decide is how much can you spend? Reduce the number of shortlisted power banks by discarding the power banks that are not in your budget. Be realistic, conciliate with the fact that you cannot find a 14000mAh power bank for 5$. If you want a particular power bank that is out of your budget, Google it, you may get some good deals on it. See all 11 photos Is the power bank compatible with my phone/tablet?Now that you have reduced your list to a few power banks, you need to find out a few more things. Power banks have an output current rating, generally in Amperes. You need to find out the current rating of your phone/tablet and make sure it matches the power bank's output current rating. Say the power bank has a rating of '1.5 A'. Now if your phone/tablet has a rating of '1 A', then the phone will take less time to charge than it usually takes but it will heat up the battery and may even damage it. If your phone has a rating of '2 A', then it will take more time than usual to charge the phone. If your desirable power bank has a different current rating than your phone, then it's not a big issue, but for the best performance i exhort you to find compatible power bank. Is the power bank reliable, safe and easy to charge and use?There are some power banks out there that can ruin the devices by overheating them or by providing uneven current output. Read the user reviews to find out these type of issues. Make sure that the power bank is manufactured by a reliable brand and is safe to use. Most power banks does not come with a charger, they come just with a USB cable and you have to use your mobile or tablet charger to charge the power bank. If you going for a power bank with big capacity, say 10000mAh or above, then it makes sense to invest in a charger with high output current rating like 2A (check if you already have one with you). It will help to charge the Power Bank faster. See all 11 photos Source: groupon.co.in Is the power bank portable?The Bigger, The Better is not applicable here. Smaller the power bank, greater is the portability. But everything comes at a price, smaller the power bank, less energy it can hold. So you need to decide what you want. In my opinion, power banks which can be easily put in pocket are great for one day outing and camping. See all 11 photos A power bank with LED What extra features does the power bank have?Some power banks have extra features like LED or automatic charging cut off. Some power banks have two output ports so you can charge two devices simultaneously. If you are ambivalent about a power bank, you can try to find out if the Power Bank has any extra feature. All the above question will help you to decide the power bank to buy. But if you need more information or have any question, please ask in comments. I will be happy to answer. Anker 2nd Gen Astro E4 13000mAh External Battery Rate Me! 1 2 3 4 5 4 stars for Anker 2nd Gen Astro E4 13000mAh External Battery My personal choiceI personally use Anker 2nd Gen Astro E4 power bank. It has capacity of 13000mAh and works at 80% efficiency. It charges my Nexus 5 about 5 times. It comes with two charging ports and has a LED light too. Only downside is that it is bit bulky and heavy, thus cannot be kept in pocket. See all 11 photos Anker 2nd Gen Astro E4 13000mAh External Battery
