Buy Qi Power Bank X 10, 000mAh Wireless Cell Phone Battery: Portable Power Banks -FREE DELIVERY possible on eligible purchases. 14/09/2018 · And they come in every size and capacity and price range to keep your device going when your battery icon starts to dip in the red. And it doesn't end there. Some power banks are equipped with features like fast charging, wireless charging, built-in cables, AC adapters, LED flashlights—even the ability to jump-start your car. Power banks are always there to come in clutch and save your iPhone and offer anywhere between 1 and 5 charges depending on the size. They can be kept in cars, purses, or even do double the work and be your phone case too, making them incredibly versatile and useful. In this review article, we’ll show you some of the best power banks for iPhone. Thanks to advances made in both Li-Poly and Li-Ion battery cell technology, power banks offer different capacities starting from 2000mah, although the power bank 10000mah capacity is now typical through to a power bank 20000mah capacity and even higher – sufficient to fully charge most modern phones and tablets multiple times.