India, Oct. 1 -- Portable chargers usually solve one problem by creating another. A large battery gives you more backup, but it also means carrying extra weight and bulk. Xiaomi's UltraThin Magnetic Power Bank 5000 15W takes the opposite approach by prioritizing portability over sheer battery capacity.

At only 6 mm thick and 98 g, it is designed to stay attached to the back of a phone without turning the combination into an awkward brick. Its 5,000 mAh battery, magnetic wireless charging, and USB Type-C output make it flexible enough for short trips and everyday top-ups rather than multi-day backup.

That compact approach comes with an important limitation. Although the power bank supports wireless output of up to 15 W, that maximum spee...