INIU Pocket Rocket P50 45W Mini Power Bank 10000mAh

A railfan's phone does a lot of work at the lineside: it holds the map to the spot, the train-tracking app, the timetable and the camera. Waiting for a train that may be late means the battery drains while you stand still. A small bank that fits in a jacket pocket lets you keep the phone going through a long wait without carrying a bulky brick, and the attached cable means one fewer loose item to forget in the car. On a longer outing with several stops, topping up the phone between locations keeps the camera and navigation available when the light and the trains finally line up. A power bank does nothing for safety near a track; it only keeps the phone running.

The maker describes the bank as able to charge three devices at once, with a small display showing the remaining charge. The cable is built into a lanyard, so the bank can hang from a bag strap or be clipped to a pack. In testing it delivered full-speed charging to phones that support its protocol, and it was comfortable in a pocket. Plan around its limits: charging several devices together is slower than charging one, and it is a phone and handheld charger first, not a substitute for a large laptop battery.

Expert pick · TechRadar: In hands-on testing the reviewer found the P50-E1 very compact and light, with above-average conversion efficiency and fast phone charging. He noted that it throttles on laptops and cannot reach full speed on phones needing higher voltages. Read the review

Anyone who spends long, idle stretches at a platform end or a roadside pull-out and relies on a phone for maps, tracking and photos. It suits people who want a light, single-purpose bank for a day trip and a phone that supports fast charging. It also suits someone who wants a second small device, such as a handheld game console, topped up on the same trip. Buyers with a laptop or a very demanding handheld should read the limits above first, since the bank slows down under sustained heavy loads.

The 4Smarts 10,000 mAh 45 W bank, which TechRadar compared directly: it is heavier at 200 g, runs warmer under load and has no USB-A port. For a larger reserve, choose a higher-capacity bank, accepting the extra weight and bulk in the bag, and checking that its output voltage suits your device.