• Read more: Best cell phone provider (opens in new tab) Unhappy with the size of his power bank, Geng upgraded to a larger one. “But when I mentioned its capacity to my friends,” the comedian and artist explained in his YouTube video, “I didn’t expect [them] to have larger ones. After they left, as an ambitious person, I couldn’t fall asleep for several nights, so I decided to make a super large, mega power bank.” The result of such gadget envy ended up becoming a truly monstrous power bank with a ludicrous capacity of 27,000,000 mAh, built by Geng’s own hands in his workshop. It is capable of charging 5,000 smartphones at any one time. To begin his project, he built a metal frame about the size of a large family table. This was designed to support what can only be described as an ‘industrial’ sized battery. This was then encased in wood panels and metal sheeting to resemble the rounded form factor common to most power banks. Geng then added wheels to the bottom of the frame. With a couple of car batteries and panels of 60 plug sockets thrown in for good measure, Geng’s ‘mega battery’ was complete. “It can not only charge many phones at one time, but it can also charge power banks and a laptop,’’ explained Geng. He even demonstrated how the power bank can power a television and washing machine outdoors. “My brother and friend are very surprised and can’t stop praising my technique,” he said. Of course, what Geng sacrificed for all that brute battery power was portability. Rather than simply sliding a power bank into your bag, this monster requires being dragged around by a rope. We would suggest that a more modest 20,000 mAh power bank might be a little more pocket-friendly… Read more Best cordless phones (opens in new tab) Best home computers (opens in new tab) Best laptops (opens in new tab)