there is no best power bank in the market because it varies of individual need and consumption.
but when it comes to your particular need then home made power bank is the best. the only down side is that it's not neat and therefore not potable.
it's not something you can boldly carry around.
but when it comes to your particular need you can built any mAh of your choice.
how to build this power bank?
first get a car charger.
the charger that is used to charge phone from car.
with car charger you can connect it with dry cell motor battery or any other battery.
how?
open the car charger and after that look for the positive and negative contact. and then connect according to any battery that is up to atleast 9 voltage and 12 voltage maximum. car battery is 12 voltage.
this will charge your phone.
what battery can I used?
the list of battery are endless. as you can possibly used any battery. if the battery is not up to 9 voltage maybe 3.7 voltage then you will need 3 of it that's about 3.7 * 3 = 11.1 voltage.
if the battery is 1.5 voltage then you will need 6 of it.
1.5 * 6 = 9 voltage
another good battery is laptop battery.
if you have any dead or not working laptop battery. or any you don't use anymore then you are good to go.
1, crushed the laptop battery and open.
2, but first you have to check if the battery inside can still hold current very well If boost and then charged.
3, you will see about 6 small dry cell battery inside. every one of it is about 3 voltage.
4, but first you have to learn about voltage and mAh.
how? to increase battery voltage...
example. if you have 3 battery of 3 voltage each and you need 9 voltage. you will have to connect the 3 battery positive to negative each. leaving the first battery positive and the last battery negative.
and if you only need 3 voltage but want to increase the mAh the 3 battery will be connected with the three negative together and the three positive together.
this will increase the mAhs * 3.
also you can used phone battery as well.
you just made a big power bank battery.
best power bank you can ever get is home made power bank.

I must try this experiment this weekend some Dexters Lab things

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Nice one

Femiali:
there is no best power bank in the market because it varies of individual need and consumption.
but when it comes to your particular need then home made power bank is the best. the only down side is that it's not neat and therefore not potable.
....
best power bank you can ever get is home made power bank.

how do go about the charging port