Four-cell portable power bank

How much power does a power bank give a phone?

Our testing shows that a power bank can offer your phone between 70-80% of the power it contains, or more depending on the battery. 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 invest in a portable power bank?

The good news is you can prepare for—and avoid—these stressful scenarios by investing in a portable power bank. Also known as mobile chargers or battery packs, these nifty gadgets serve as a lifeline to your dying electronics by recharging battery power when needed.

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 various sizes and capacities, and can include handy features such as fast charging and multiple ports.

What are the best portable chargers & power banks in 2025?

November 18, 2025: With this update, our lineup of recommended portable chargers and power banks remains unchanged. The existing picks have been vetted for currency and availability. The Anker Laptop Power Bank has a capacity of 25,000mAh, but more importantly, it can deliver 100W of power from a single port.