Anyone who uses a smartphone knows the importance of carrying a backup battery pack. But given the large number of options on Amazon, you might feel overwhelmed, understandably. Besides the various charging specs, ports, and even cables you have to consider, there are a ton of competing brands. But how do you know which ones actually deliver on their promises? Is it worth saving a few bucks if a battery pack’s performance is lacking?

We decided to do the legwork for you, acquiring a wide range of power banks from different manufacturers, some offering unique features. We then spent weeks testing the packs (read about our testing process in detail below).

While we’ve made some top picks, be sure to read through each review, linked to at the bottom of this page, to help you find the best power bank for your needs. (You might also be interested in our our roundup of USB car chargers if you spend a lot of time in transit.)

Updated 5/11/2020 to include our review of the Elecjet PowerPie 20000mAh 45W PD battery pack, which is powerful enough to charge a Macbook, but small enough to carry in a purse. Scroll to the bottom of this article to see all our power bank reviews.

Mophie's Powerstation XXL surpasses its Powerstation XL predecessor to become our new favorite portable power bank. Well done.

Building on the success of the Powerstation Plus XL (our previous pick for best overall power bank), Mophie’s Powerstation XXL matches its predecessor in efficiency, achieving 92.51 percent of its stated maximum current, plus it’s stylish, portable, and affordable at $69.95. It’s a no-brainer recommendation if you’re in the market for a dependable power source on-the-go. (Read our full review of the Mophie Powerstation XXL.)

At this price point and with this performance, you simply can’t go wrong with the Mi Power Bank Pro. Not only is it small enough to tote around anywhere, it's capable of charging all the things.

Xiaomi is known for producing high-quality products and selling them at an affordable price. The 10,000mAh Mi Power Bank Pro is a prime example of that approach, hitting all the marks to make it our top pick for the most portable power bank overall. With its high efficiency, premium design, and street price of $28, it’s hard to beat. Pick up one or two of these, throw them in your bag and suitcase, and forget having to worry about running out of battery power while on the road. (Read our full review of the Xiaomi 10,00mAh Mi Power Bank Pro.)

If you spend a lot of time on the road and value device preparedness, the Sherpa 100AC makes a trusty, if pricey, companion. Yes, at $299.95, you’re looking at a big investment. But that buys you two USB-C ports capable of fast-charging speeds, two standard USB ports, a Qi wireless charging pad, a standard U.S. 110V outlet, a full complement of cables, and a nifty status display and buttons for controlling various functions of the pack. The pack itself can be charged in just a couple hours. (Read our full review of the Sherpa 100AC Portable Power Bank.)

Fast charging, quickly charged, wide range of compatibility... what’s not to love?

Between its capacity, recharge time, charging capabilities, USB-C, and the wide range of devices it can charge, the Anker Powercore+ 26800 PD is well worth its $110 price. 

Yes, it’s big and bulky. But being able to quickly top off your phone while trekking through The Legend of Zelda: Breath of the Wild on the Nintendo Switch simultaneously is worth the added weight and the price. (Read our full review of the Anker Powercore+ 26800 PD.)

The RockPals 300W Power Station is a beast, sporting a plethora of ports and performing with exceptional efficiency. It's a handy backup power source to have in an emergency.

There are power banks, and then there are power stations—behemoth chargers that pack serious capacity and offer an excess of ports. In this category, RockPals’ 300W Portable Power Station stands out. It boasts 280 watt-hours of capacity, a total of 10 different ports including four USB ports—two of which are Quick Charge 3.0 compatible—a 110V AC outlet, and a 12V/8A cigarette lighter. It can be recharged via AC, car charger, or the optional 100W/60W solar panel accessoryRemove non-product link that RockPals also offers for an additional $199. (Read our full review of the RockPals 300W Power Station.)

Determining whether a power bank lives up to a company’s promise entails more than simply connecting it to a phone and charging. Testing battery packs is done over weeks, not days, and requires extra equipment in order to ensure the batteries work as expected.

Using the DROK load tester to drain the pack of power, we were able to test against a battery’s stated maximum current, and verify that proper shutdown mechanisms were in place should something go wrong during a charging session (such as a device drawing over the maximum amps).

By using the PortaPow Power Monitor, we were able to monitor volts and amps, total power throughput, and total amount of time to deplete a battery from full to empty.

There are some hiccups using this method, however. We had to use a GoPro camera to track each battery through its charge cycle, due to the PortaPow monitor continuing to collect data after the battery was fully charged (trickle charging is normal, and unfortunately interferes with our testing).

If a battery was capable of charging through USB-C, we used that instead of Micro-USB.

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.

Without fancy testing equipment, you never truly know if you’re getting what you paid for with a battery pack. Vendors, especially in Amazon listings, like to throw around a lot of terms and certifications.

Here are a few tips to help you make a decision:

Click on the links below to read the full reviews of all the products we tested for this roundup. We will continue to review and update this article as we test more battery packs.

You may also be considering simply buying Amazon’s AmazonBasic charger, as a way of saving money. In this case, be advised: Amazon has voluntarily recalled several models because of potential overheating. Amazon has received 53 reports of the affected models—B00LRK8EVO, B00LRK8HJ8, B00LRK8I7O, B00LRK8IV0, B00LRK8JDC or B00ZQ4JQAA—overheating, and in one case causing chemical burns. You can find more information at the Consumer Products Safety Commission, as well as Amazon’s own recall site. 

This story, "Best power banks 2020: The top portable chargers for your phone" was originally published by PCWorld.