Before you purchase an power bank you would put an eye on how many times power bank totally charge your device, for example, if it's a 10000 mAh rated power bank, you would possibly expect to charge your 2000 mAh phone for 5 times, really it's a totally wrong calculation technique.
First of all, you would like to consider the power conversion rate that is thought to be efficiency. once power is transferred from an power bank , there's continually loss because of resistance.
Obviously, a 20,000 mAh power bank can hold additional of a charge than a 10,000 mAh power bank. however it should not essentially be double, depending on the electronic equipment within and quality age of the battery. Lithium-ion batteries degrade over time, their capability to carry a charge diminishes bit by bit.
Also, if you have got a phone with a 2,000 mAh battery, you may not be able to use a full charged 10,000 mAh battery to charge your phone 5 times. this can be as a result of a number of the capability of the power bank is lost in conversion.
The battery of the power bank itself could have a voltage of 3V however it uses electronic equipment to raise the output to 5V there's a loss in conversion.
Almost each cellular phone or laptop computer charger can have some small print on that, you will see specifications for input and output power. The input can usually be AC a 100 to 240 volts this signifies that it's a universal voltage charger and can work anyplace within the world.