In fact, our testing confirms what battery makers usually claim. A battery maker will claim between 60% and 70% efficiency, so that 10,000mAh battery will only give your phone around 6,000mAh of extra battery charge, at the least. In practice we find around 65% efficiency, though occasionally we can do even better.

You're trying to keep it simple: The Baseus Airpow doesn't have any built in wires or wireless charging, so you'll need to carry extras when it's time to power up. 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. 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.When you're after a power bank for a camping trip or weekend getaway, or to power your Switch or laptop, you'll want something with a higher capacity. All of our tests were conducted using the same wall adapter and, when possible, USB-C or Micro-USB cable. This was done to eliminate any discrepancies with wall adapters and cable throughput. What to look for in a portable power bank Dimensions: 9.91 x 6.4 x 1.65 cm | Weight: 173g | Capacity: 5,000mAh | Ports: USB-C (input and output) and wireless charging

You have a watch that isn't from Apple: The Otterbox 2-in-1 Power Bank only attaches magnetically to the Apple Watch. Other smartwatches, like the Pixel Watch, won't work with this one, not at all. 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 Nano is only 5,000mAh, but that doesn't mean it can fully charge a 5,000mAh phone battery like you'll find in the Galaxy S23 Ultra. Power banks are about 60-70% efficient, depending on the phone's technology, so this power bank is good for charging an iPhone 15 to nearly full, but that big Ultra will only get about 65% charge.Using the Anker Prime power bank, we were also able to test the charging speed claims of other power banks, as the Anker Prime will report charging speed in wattage. If you care more about convenience than speed, wireless charging is very much the way to go – and a growing number of power banks support it. Just place your smartphone on the integrated wireless pad, and you can recharge without connecting any cables. There will be a hit on charging speeds, so you’ll be limited to 7.5W or 10W, but that’s not a big issue if you don’t need to recharge in a flash. As a bonus, we’re now seeing Magsafe-friendly chargers that will clamp onto an iPhone or a ring inside an iPhone case, meaning you can recharge your iPhone even while you’re using it. How we test power banks 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? You don't need all those extras: The Anker Prime power bank is pricey, and if you don't care about monitoring charge Wattage or days of battery life, find another option. 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 power for your phone: The 3,000mAh battery inside is plenty to keep your Apple Watch going, but that isn't enough power to get you even halfway charged on an iPhone 15, and even less on bigger phones.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. There are plenty of combination power bank and some other device, but the Tylt Bottle 2 actually makes sense because we're usually carrying an insulated water bottle anyway, so we might as well screw a battery onto the bottom. With a 5,700mAh capacity, the Tylt Bottle 2 is just enough to get us through a very busy day, or keep the phone powered while we play games at the cafe. 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. To test charging times and claims, we charged a Samsung Galaxy S23 Ultra and an Apple iPhone 15 to determine how many charges each battery offers these devices. We chose a common smaller battery phone as well as our best phone overall for this purpose. 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.