I tested this cheap 9,000,000mAh battery pack from eBay – here’s my buying advice
Adrian Kingsley-Hughes/ZDNETA power bank boasting a massive capacity of 9 million milliamp hours (mAh) that fits in the palm of your hand, all for just a little over $10, sounds too good to be true, doesn't it? Well, you know what they say.A reader brought this listing to my attention, questioning the validity of such bold claims. Although I harbored significant doubts, I decided to investigate further. All in the name of science, of course. Also: The best iPhone power banks you can buy: Expert testedFirst, let's put…