Which Features Do You Need in a Power Bank?
Watching your phone or tablet steadily run out of juice when you’re nowhere near a power outlet is stressful. Fortunately, there’s no shortage of third-party backup batteries, and they come in every size, capacity, and price range to keep your device going when your battery icon starts to dip in the red. And it doesn’t end there. Some power banks are equipped with features like fast charging, wireless charging, built-in cables, AC adapters, LED flashlights—and even the ability to jump-start your car.
With so many options to choose from, how do you know which power bank is right for you? Read on for the most important points to consider.
Size and Capacity
Generally speaking, the bigger the battery, the higher the capacity and quantity of ports you get. Power banks that fit comfortably in your pocket are typically good for a full phone charge or two, while anything designed to keep you going all day is going to require a bag or a purse.
On the pocket-friendly front, most smaller batteries that maximize portability have a capacity of 5,000mAh and under, which gives you just enough charge to top up most phones once.
Once you get above 5,000mAh, battery size increases to the point where it’s less likely to fit into your skinny jeans but can still be stowed in a jacket pocket. There are even batteries that let you power laptops and have enough juice to charge the average phone 10 times. Of course, they’re some of the biggest and heaviest of the bunch, and definitely need to be carried in a bag.
Input and Output Ports
The type of port (or ports) a battery has determines not only whether it is compatible with the devices you want to charge, but also charging speed. At a minimum, most battery packs will have a standard USB-A port for both charging the battery (power input) and sending juice to your device (power output). But with most phones, tablets, and laptops adopting the USB-C standard, you’ll often find a USB-C port in addition to USB-A.
USB-C ports typically support some, but not all, fast charging protocols for smartphones and tablets. Most often you’ll find the USB-C port is used for both power input and power output, but you’ll want to check carefully since some less expensive battery packs may only USB-C for power input.
Lightning is a proprietary Apple technology and it used to be hard to find power banks with a Lightning cable or charging port. Thankfully, those days are over and there are dozens of excellent power banks made with iPhone users in mind. If you picked up an iPhone 12 series phone and were surprised by the lack of charger, see our article on charging your iPhone 12.
Another factor to consider is how quickly a power bank can charge your phone. Battery output is measured in voltage and amperage. Amperage (or current) is the amount of electricity flowing from the battery to the connected device, while voltage is the amount of potential energy. Multiplying volts by amps gives you wattage, the measure of total power. In order to make a device charge faster, most manufacturers either vary the voltage or boost the amperage in order to increase the total wattage. For most fast charging, you’re looking at boosting or dynamically varying the voltage.
Essentially, for any kind of fast charging you need three things: A phone or other device with a charging circuit capable of using one of the fast charging standards, along with a battery and cable that support the same standard. If any one of these three things is missing, you won’t be charging as fast as you can.
The two main fast charging standards you’re likely to encounter are USB Power Delivery and Qualcomm’s Quick Charge. Power Delivery (PD) is a newer protocol in which two compatible devices negotiate on the fastest charging option available. It also allows for power to flow both ways.
Quick Charge, on the other hand, works by increasing voltage rather than amperage. This standard allows you to charge supported phones to 50 percent capacity in 30 minutes, which is especially helpful when you need power in a pinch.
Keep in mind, your phone will only take in as much power as its charging circuit is designed for, so even if you have it plugged into a 5V/2A battery, if it’s only able to handle 5V/1A, that’s the rate it will charge at.
For more, read our in-depth guide to fast charging.
Pass-Through and Wireless Charging
There are a couple of other aspects to consider before selecting a backup battery. Pass-through charging lets you charge devices connected to the battery, while the battery itself is also being charged. If both your phone and backup battery are running on empty, this is a very useful feature.
Wireless charging has also become very popular, as it allows you to power up compatible devices without the need for a cable, but simply by resting them on top of the battery. Qi is the dominant standard that you’ll find in compatible Apple and Samsung phones, and there are some battery packs out there that support it. For the iPhone 12, Apple introduced MagSafe charging, and MagSafe-compatible battery packs are starting to become available.
Should You Buy a Battery Case Instead?
If you find that you often forget to carry your backup battery when you need it most, you might want to think about using a dedicated battery case instead. It combines the portability and protection of a case with a built-in power cell to keep your phone topped off at all times. The downside is that they often have lower charging capacities than dedicated batteries, and you really can’t charge anything else with them.
Now, with all that in mind, we’ve rounded up some of our favorite power banks you can buy right now. You can’t go wrong with any of them, so pick the one that fits your budget and needs.