There are six power banks on my desk right now. On the shelves behind me are a dozen (two dozen?) more. Over the past three years, I’ve tested more than 55 portable battery packs for Engadget — and can attest these handy devices are only getting better. If you often forget to charge your phone or find yourself traveling for work or leisure, having one of these in your bag can be a lifeline. Here you’ll find banks ranging from Qi2-enabled slabs for wireless phone refills to larger bricks that can save a dying laptop. Here are the best power banks you can buy, according to our tests. Table of contents Best power banks for 2025 How we test best power banks What to look for in a portable battery pack Other power banks we tested Power bank FAQs Best power banks for 2025 What to look for in a portable battery pack Battery type Nearly every rechargeable power bank you can buy (and most portable devices) contain a lithium-ion battery. These beat other current battery types in terms of size-to-charge capacity, and have even increased in energy density by eight fold in the past 14 years. They also don’t suffer from a memory effect (where a battery’s lifespan deteriorates due to partial charges). Flying with portable batteries You may have heard about lithium ion batteries overheating and catching fire — a recent Hong Kong flight was grounded after just such a thing happened in an overhead bin. Current restrictions implemented by the TSA still allow external batteries rated at 100Wh or less (which all of our recommendations are) to fly with you, but only in your carry-on luggage — they can’t be checked. Recently, Southwest Airlines was the first in the industry to take that rule one step further. Now, flyers on that airline must keep power banks in clear view when using them to recharge a device. If the portable charger isn’t actively in use, however, it can stay in your carry-on bag in the overhead bin. Capacity Power bank manufacturers almost always list a battery’s capacity in milliamp hours, or mAh. Smaller batteries with a 5,000mAh capacity make good phone chargers and can fill a smartphone to between 50 and 75 percent. Larger batteries that can recharge laptops and tablets, or give phones multiple charges, can exceed 25,000mAh and we have a separate guide that covers that entire category. Unsurprisingly, the prices on most batteries goes up as mAh capacity increases, and since batteries are physical storage units, size and weight go up with capacity as well. If you want more power, be prepared to spend more and carry around a heavier brick. You might think that a 10,000mAh power bank could charge a 5,000mAh phone to 100 percent twice, but that’s not the case. In addition to simple energy loss through heat dissipation, factors like voltage conversion also bring down the amount of juice that makes it into your phone. Most manufacturers list how many charges a battery can give a certain smartphone. In our tests, 10,000mAh of battery pack capacity translated to roughly 5,800mAh of device charge. 20,000mAh chargers delivered around 11,250mAh to a device, and 25,000mAh banks translated to about 16,200mAh of charge. That’s an average efficiency rate of around 60 percent. Wireless Wireless charging, whether through a bank or a plugged-in charging pad, is less efficient than wired connections. But it is convenient — and in most cases, you can carry around and use your phone as it refills with a magnetically attached power bank. Power banks with wireless charging are far better than they once were. Just a couple years ago, the ones I tested were too inefficient to recommend in this guide. When batteries adhering to the Qi2 wireless charging standard started arriving in 2023, performance markedly improved. To gain Qi2-certification, a device has to support speeds of up to 15 watts and include magnetic attachment points. The MagSafe technology on iPhones were once the only handsets that were Qi2-compatible, but now Google’s Pixelsnap tech brings both the higher speed and magnetic grip to Pixel 10 phones. Samsung may follow up with its own version in future releases. The latest wireless charging standard, Q12 25W, is supported by the new iPhone 17 phones as well as the Google Pixel 10 Pro XL. Battery packs that are Qi2 25W-enabled are starting to hit the market as well, and the Ugreen MagFlow was the first on the scene. Ports USB-C ports can deliver faster charges than USB-A ports, and most of the portable chargers we recommend here have Type-C connections. But Type-A jacks are still handy if you need to use a specialized cable for a certain device (my camera’s USB-A to micro USB cable comes to mind). There’s also variation among USB-C ports. Larger banks with more than one port will sometimes list different wattages for each. For example, a bank with three ports may have two 65W ports and one 100W port. There will also be at least one in/out port on the bank, which can be used to charge the battery itself or to deliver a charge to your device. Wattages and in/out labels are printed right next to the port — and always in the tiniest font possible (remember, your phone is an excellent magnifying glass if you ever have trouble reading them). As with standard wall chargers, the port’s wattage will determine what you can charge. A phone will happily charge off a 100W connection, but a 15W plug won’t do much for your laptop. And remember, the cable has to match the maximum wattage. A cable rated for 60W won’t deliver 100W speeds. Luckily, some of the best power banks include a built-in USB-C cable. That’ll not only ensure you have the right cord, it’s one less thing you have to remember to bring along. Design Once, most rechargeable batteries were black with a squared-off, brick-like design, but now they come in different colors and shapes
