Why we never get full efficiency from a powerbank?

Now a days we travel a lots of time and during travel the most important thing is mobile. We always check our phone's charge. we always charge it full before going to somewhere. we also need more battery to get long battery life from a phone. That's why a power bank is really essential during travel. You always want to carry a power bank with you. Power banks have different capacities. The capacity is measured in mAh. So you will find power banks starting from 3000 mAh capacity. But we always buy at least 10000 mAh power bank.
       
Now the big question is have you ever get an output of 10000 mAh output from your power bank?  The answer is never. Will you get in future? no never. Now you may think that the power bank companies are making us fool. But actually they are not making us fool. They give correct information always except the fake companies. If you buy a branded power bank you will not be cheated.
 
Does Powebank companies are cheating with us?
Does powerbank companies are doing scam?
 
Answer is no. Where do we do mistakes during buying a power bank?

             When we look for a power bank we always look the capacity and at the same time we look our phone's capacity. Here we use a simple math to know how many times we able to charge our phone using this power bank. Suppose you buy a power bank of  15000 mAh and your phone's capacity is 3000 mAh. You think that you can charge your phone for five times(15000/3000=5 times). But have you ever get 5 time charge from your power bank. you will never get it because there works a lot of things fow which you never get 100% output from your power bank.

What are the factors work for which a powerbank does not give 100% output?

      There are mainly two reasons for which this actually happens. At first 
 1. Voltage up and down conversion and
 2.The losses( heat + resistance).

Reasons why output of power bank is not 100%

         1.Voltage up- down conversion: You have to understand you never get 100% output. You may  notice that your power bank voltage is 3.7 volts. But the usb port by which you connect your phone with power bank, will charge your phone at 5 volt. So here you can see a clear difference between this voltage. But the best suitable voltage for normal charging ( no fast charging) for our phone's battery is 4.2 volt to 4.4 volt which is considered as standard and ideal. Now if you use a power bank at first here it will do a voltage up conversion and then it will do a voltage down conversion to get a suitable condition. So during voltage conversion your power bank loses some energy which it stores. Now how much energy it will loss. There is  simple math formula by which you can get idea how much power here your power bank will loss.

    The formula is (Power bank capacity -(power bank's capacity)*(3.7/4.2).

Now suppose you have a power bank which has a capacity of 10000 mah. now you can calculate how much your power bank loses during conversion. Here the loss will be (10000-(10000*(3.7/4.2))) = 1190 mah. So here you will loss 1190 mah from the battery capacity. The remaining battery is 8809 mAh. So during this conversion you will loss energy. Now let us come to the second reason.


         2.Losses: Here you can say it acts a major role to decrease the power bank capacity. losses are different types of losses 

1. Resistance loss,  
2. heat loss.

 Here heat plays the major role. You can calculate overall losses due to heat and resistance which is 20-25%. so it is a big loss. mainly for that power bank never give you 100% output. we all know from Joule's law of heat. Here due to heat you will lose capacity. Now if you take 20% of your remaining battery it will be (8809*20)/100 =1761. So total loss = heat loss + conversion loss = 1190+1761=2951. It is near about 3000 mah loss.

 So here you will lose 3000 mAh of capacity and you will get 7000 mAh output from your power bank which you never expected you will get during buying it.

Be aware about the fake brands

   There are a lot of companies who sell fake power bank. This may harm your phone as well as your battery. Here you may be cheated. They may give you incorrect information to sell products. So before buying a power bank you should go for a proper brand to keep safe your battery 

Conclusion:

  So I hope after reading this article you have understood how power bank's capacity decreases, you are not cheated by companies. They give you the correct one and you may see in the box that they mention about the losses.