Does the device you’re trying to charge work? In a scientific experiment, researchers will establish a “control” group to serve as a baseline to compare their results to. If you’re mainly using your power bank to charge one device, try it with a different one. This will help you determine whether the problem is with the bank itself and not the other device. Make sure you’ve established that the phone or other device you’re using for this test works properly. And that's basically what I did. The power bank came in handy when trying to locate a friend to meet for a swim on Hampstead Heath (my phone was on its last legs – isn't it always?), and during last ditch attempts to keep my nieces and nephews entertained with games on long journeys (there’s only so much I Spy any sane adult can handle). It takes around three hours to charge from empty (considerably less time than the Juice Power Station), and once charged, Belkin says its tests show that charge will not diminish by more than 50pc even after a year’s time left dormant – all very impressive, and useful. Tylt also wisely left enough of a gap between the battery and the bottle that you can coil a small USB-C cord (included) into that space. That way, even if you're not charging wirelessly, you're not adding a lot of extra bulk to your bag. It's a smart setup.

That means I could twist my phone sideways into landscape mode and use the Baseus power bank as a portable stand for Apple's new StandBy mode, which is one of my favorite features on iOS 17, and certainly the one I use the most often. Step up from the budget power banks to the mighty Juice Powerbank Max and you get a much more capable mobile charger, with a 20,000mAh capacity and a 20W USB PD output over USB-C. We measured the USB-A output at nearly 15W in our tests, which recharged our smartphone by 18% in 15 minutes. With USB-C, that output rose to just over 19W, which was good for a 22% recharge in 15 minutes. That’s not bad at all for an affordable power bank, and we also found it usable for charging tablets and even a Chromebook laptop, albeit at a slower-than-usual speed.Why we like it: The Daddy of the power banks we reviewed. Powerful, well designed, not too heavy, and brilliantly priced. The use of USB-C for the single input/output port is a little weird given the target market, and you’ll need a fast USB-C charger and a USB-C to Lightning cable to make the most of the device. What’s more, the wired charging isn’t super-speedy; our Android test smartphone only recovered by 11% from a 15-minute charge. But if you’re an iPhone user looking for a light and convenient portable charger, the Anker 622 is almost perfect for the role. Battery Age: Battery technology is improving all the time, but even the latest and greatest are still mortal, especially batteries that are frequently and irregularly charged and discharged (like power banks and smartphone batteries). If you’ve had your power bank more than two or three years and use it often, you may’ve simply worn your battery out.

You don't have a magnetic phone: You don't need an iPhone to enjoy the magnetic charging, but you'll need a case that lines up your phone with Apple's MagSafe wireless configuration, or else your phone won't charge properly. Basically, you’re trying to balance four factors: size, speed, capacity and price. The rules are simple enough: the less you spend, the lower the capacity and the slower the power bank will charge. The most important question to consider when buying a power bank is what will you be charging? If you are charging a small smartphone and that's all, a simple power bank will suffice. If you plan on charging a laptop occasionally as well, or many devices at once, you'll want something with more power and more features.In terms of charging, this massive power bank can charge an iPhone 15 more than five times. It can charge a big Galaxy S23 Ultra's 5,000mAh battery three-and-a-half times. Best of all, it charges at the fastest speed available on most of your favorite phones (excluding Oppo/OnePlus's unusual SUPERVOOC battery). The Anker Prime series of Power Banks, including the Anker Prime 27,650mAh Power Bank (250W) and the Anker Prime 20,000mAh Power Bank (200W), are for people who truly love to geek out on power banks. If you came looking for the absolute best power bank you can buy, this is the best we've tried.