Our favorite power bank has a 10,000mAh battery, and the Samsung Galaxy S23 Ultra has a 5,000mAh battery, so the math should be simple, right? It charges twice. Except that's not how it works. Power banks are not 100% efficient, and even though you start with plenty of power, a lot of it is lost in the charging process.

If you’re trying to understand watt hours, voltage and power management, then shopping for portable chargers can become a little bit daunting. You only want to charge a phone: If you don't need to charge a laptop occasionally, or you only carry a phone with no accessories, the Anker 733 is more than you need. While it’s big compared to some of the others on this list, this chunky model is the best power bank to invest in if you want a versatile and impressive battery to charge up your laptop, iPad, phone and everything in between. It’s best to look at the main battery you’ll need to fuel up – we’re guessing it’s your phone – and work out how large of a power bank you need (of course, all phones have different battery sizes). The capacity is measured in milliamp hours (mAh) and the more you have, the more recharges you’ll get. 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.Charge it Fully: Plug in your power bank and let it charge fully before using it. This ensures that it's ready to provide a reliable power source when you need it. The best power banks we have tried have all come from Anker, but that doesn't mean Anker is the only brand you should consider. 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, but these batteries from Baseus and Otterbox performed well. 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.

We have tested the best power banks by using them to charge a variety of devices, including Apple iPhone, Google Pixel, and Samsung Galaxy phones. We have also charged Apple iPad tablets, and small laptops including a Pixelbook Go and a Surface Laptop Go.We expect this competition will heat up next year as more power bank makers catch up and make faster charging batteries. Until then, Anker is the dominant brand, and if you want the best it's an easy choice. How many times can my power bank charge my phone? The bottle is actually a nice, insulated affair, and it kept ice in cold water for 12 hours, which is all that we need. It has a good, strong strap to carry the bottle, though we would have liked a lid that was easier for sipping. You need fast power: This is a very slow charger, whether wired or wireless, so it's better for casual charging while you sip your water and read a book. Apple doesn't publish its battery capacity, but teardowns have shown that the iPhone 15 has a battery with around 3,350mAh of battery life. That means a 10KmAh battery can charge that phone twice ... almost. You may not get to 100% the second charge, but you'll be in the 90% range. But, you only need to worry about the basics to make sure you’re getting the right one for your needs. Most importantly, is it the right size and weight for your needs? Does it have enough ports? And is there enough juice to charge up all your devices? Capacity

Read the Instructions: Take a few minutes to read the user manual that comes with your power bank. Familiarize yourself with its features, usage instructions, and safety precautions. This will help you make the most of your new gadget while keeping yourself and your devices safe.While you’ll probably have most of the cords that you’d need, we’d expect a power bank to at least come with a recharge cable and maybe some extra useful wires. It’s also a nice extra when it comes with a decent carrying pouch to keep the battery and cables together. What is the largest power bank allowed on a plane? Think about how you’ll be carrying it around and what you need it for – a power bank for your bag can be quite different than one for travelling or camping. We wish there wasn't such an easy answer to this question, because competition is better for everybody, but Anker is making the best power banks right now by far. It offers the best power-to-weight ratio, the fastest charging, and the most useful features.