Do you need a portable battery or power bank?

Watching your phone or tablet steadily run out of power when you're nowhere near an outlet is stressful. But there's an easy solution: a portable battery or power bank. They are available in many sizes and capacities and can include handy features like fast charging and multiple ports.

How much power does a power bank give a phone?

Our testing shows that a power bank can offer your phone about 70% of the power it contains. It loses the rest due to the inefficiency of the power transfer. That means a 5,000 mAh battery can fully charge a phone with a 3,500 mAh battery, like an iPhone 16.

Should you buy a power bank?

Those who only need a power bank for occasional smartphone charging may find this device overkill for their needs, while those on a tight budget might want to explore more affordable options, as this power bank's advanced features and high output come at a premium price.

What is a power bank & how does it work?

An integrated metal stand provides support for the power bank so you can use your phone in Standby mode while it's charging. The power bank’s most distinctive feature is its smart display, which uses emoji faces to indicate battery levels. These animated expressions can easily be disabled if you're not in the mood.

Which power bank is best?

All of the power banks on this list passed our testing, traveling with us on the road and powering our devices at home. Anker is the best in part because it packs more power into its batteries at a lower weight. Its batteries charge faster than competitors. Its small Anker Nano battery has the best power-to-weight ratio of any battery on our list.

How efficient is a power bank?

Power banks are about 60-70% efficient, depending on the phone's technology, so in our tests this power bank could charge an iPhone 15 to nearly full, but that big Ultra only got about 65% charge. That's just fine, because this power bank was the perfect pocket companion to keep us going through a busy day.