How To Choose Suitable Capacity Of Power Bank For One Day Use？

[AC Question]

If you’re going to be out of home or office for one day or a few days or your tablet/smartphone won’t keep power for a whole day then you need a power bank. A power bank allows you to keep connected with the rest of the world. What’s the suitable Power Bank capacity for one day use?

 

[ChristinaYang]

A interesting question.

I don’t know if it’s just me but I get a small satisfaction whenever I have a fully charged phone. I’m sure it’s happened to everyone before especially for those who travel often. A solution for this is to have a portable power bank on hand.

So what's the suitable Power Bank capacity for one day use? Now considering my personal needs, I work every day about 8 hours, sometimes I join some party with friends, I also go camping with family and friends about once a month, I should also have business travel about once every two weeks. So I do need to double the battery life of my smartphone and tablet every day.

Just like me, the first thing you need to ask yourself is what situations you are going to find yourself using these chargers. You may just need a little charge to your phone to get through the day but someone else may need a full charge for both their iPad and iPhone while traveling.

At this point it just becomes a math problem that how much power you need? Power in a portable battery charger is typically measured in milliamps (mAh), and these devices will typically be described with a number telling how its battery capacity. The true output rate may be lower at times. Usually the conversion rate of a good power bank is about 90%, so now we just have worked out a not so difficult math problem. Let’s suppose that the conversion rate is about 90%, how many times different devices can be charged with different power banks?



If you just want keep your smartphone double the battery life, you’d need a pack with a capacity of at least 5000 mAh.

But If you wanted a power bank that could double the battery life of your and your friend’s smartphones or double the battery life of your smartphone and your tablet, you’d need a pack with a capacity of at least 10000 mAh.

If you only care about keeping your iPad going during your flight and you’d have your phone turned off, then you could stick with a battery pack that had around the 10000 mAh capacity of the iPad to double its life.

They come in all shapes and sizes with different price tags. You may want something light and easily transportable, or you many want something bigger that can charge all your devices.

Here I want to introduce a 10000mAh Power Bank from EasyAcc: PB10000CF 2. Gen Smart Power Bank.

It is 10000mAh with 2 smart ports from 0.2-2.4 amp. What is wonderful is that this EasyAcc power bank can identify the type of device and output the suitable electric current. It means that it won’t damage your smartphone but can give fast charging just like the original charger.

 

[Rukbat]

See how many times you have to charge the device for one day's use. You should never let it drop below 40%, so take that into account. You should never let the power bank drop below 40% either, so whatever amount of power (in mAh) your device is going to need to give it a 60% charge for the amount of time you need (just add up the individual charges it's going to need), 60% of the power bank capacity should be at least that much, plus another 10% to allow for the conversion loss. (The numbers in ChristinaYang's chart assumes discharging the phone and the power bank to 0, which is a bad idea. See The Care and Feeding of Lithium Polymer Batteries.)