How Long Does It Take to Charge a 20100 mAh Power Bank?

charge a 20100mAh power bank

Have you ever plugged in the power bank for more than 24 hours and it still didn’t get a full charge? Plus, when using it to juice up your phone, you have to wait another 12 hours or even longer.

Indeed, generally the larger the volume is, the more charger you will get from the power bank. But you should never ignore the input and output rate, which directly affect the charging time. There is a formula for you to count charging time:

Rated Charging Time = Power Bank Capacity/ (input &output capacity* 85%)

Most power banks at present are designed with 5V 2A input standard, which stands for the biggest amount of flow it can accept. However, considering an estimated 15% power consumption during charging/discharging process, the actual input current would be 1700 mA (1.7A). Thereby, the charging time can be counted by this way:

Rated Charging Time = 20100 mAh / 1700 mAh = 11.82 hours

And if you are using a 1A rated charger, the charging time will be:

20100mAh/850mAh = 23.64 hours

So, it is not always the bigger the volume, the better the power bank. If it takes you more than 24 hours to full charge your phone, you would go crazy. Considering the above all analysis, you may get some idea about how to choose a good power bank. For your convenience, we’ll list some recommendations.

Zendure A6PD 20,100mAh Portable Charger

Zendure A6PD is respectable product for its high efficiency, high capacity and good compatibility. It provides USB-C maximum output and input at 45W, which ensures impressive effectiveness.

Also, it is accompanied with regular 2.4A (Max) Micro-USB input and 2.4A (Max) USB-A output, making more devices compatible with it. Generally speaking, it can fully charge your MacBook 1.5 times, iPhone X 5.5 times and Galaxy S8 4 times. As for after-service warranty, Zendure promises a 2-Year product replacement Warranty Card, which makes it both reliable and trustworthy.

Zendure SuperTank 

Recharge in 2 hours

This excellent power bank has a sturdy design that makes it practical to use and portable. 27,000mAh is a grand battery capacity but the small size mobile USB power bank makes it perfectly suited for handbags and backpacks.

SuperTank recharges itself in 2 hours with a 100W charger, which is outstanding compared with normal phone chargers (generally 1 amp) that may take up to 20 hours.

Thanks to its two PD-enabled USB-C ports and two USB-A ports, SuperTank allows you to charge four devices at the same time, including laptops, tablets, cameras, cell phones, and other mobile devices, rapid charging for two laptops or tablets and two mobile devices all at once.

In a word, there are mainly two factors that affects the charging time of a power bank, volume and input. Generally speaking, a larger capacity always accompanies with longer charging time. Except with the ultra-fast re-charge time of SuperTank!

Power Bank with 2-Hour Recharge Time


Zendure A8 26,800 mAh

Designed with QC 3.0 technology, Zendure A8 QC is one of the fastest external batteries on the market for its capacity. There is one USB Quick Charge port and three USB 5v standard ports, which ensures your other devices will work while still charging your smartphone. Weighing 17 Oz, it is outstanding for portable use. You can easily fit it in your bag to take it on your travels. Its capacity is 26800 mAh, a satisfying volume that can easily extend your phone usage 7-9 times, and take only 10-12 hours to charge using a QC3.0 charger.

Zendure A5 16,750 mAh

Zendure A5 is a respectable product that is approved and used by a number of airlines such as Titan Airways for their pilots to charge iPads. Available in silver and black, Zendure A5 automatically detects your device and fine-tunes the output to charge it at maximum speed (up to 2.1A). All Zendure A series products can maintain up to 95% of its charge after six months without use, which means that you can put it away in your drawer for 6 months and when someday you are in a hurry to use a power bank, it is always ready to go. 


Power Bank with 2-Hour Recharge Time