If you travel with any regularity or use your devices considerably outside of the home or an office, then it’s well worth having a portable laptop battery charger around for when your phone runs low or you need a little more work time before your laptop shuts off. ZMI’s PowerPack 20000 is one of the best all-around options on the market today, providing a sizable cell with speedy charging across phones, tablets, laptops, portable game systems, and more, plus a slim design and great price. I tested ZMI’s PowerPack 20000 time and again over more than a week across multiple devices, measuring the charging speeds and comparing it to other similar power banks.
Design: Small but powerful
The ZMI PowerPack 20000’s size is easily one of its biggest selling points. While it is a little heavy at 14.3 ounces, this power bank is the approximate width and height of a large smartphone, measuring up very closely to the size of my Apple iPhone 11 Pro at 6.3 x 3.2 inches (HWD). Of course, the 0.8-inch thickness is quite a bit larger than any phone today, but unlike most laptop-friendly charging banks, ZMI’s can still fit into a pocket or handbag with ease. It’s smooth navy blue aluminum on the outside with a black plastic strip running along the entire frame, with one USB-C Power Delivery 2.0 port and two USB-A ports on one end. Nearby on the upper right side frame is a power button and four small lights that indicate how much power the bank is currently holding. The button also serves another very handy purpose: press it twice in a row and you’ll enable USB devices to be used by a connected computer. I plugged the ZMI PowerPack 20000 into a Huawei MateBook X Pro laptop and then plugged a USB mouse into the power bank, pressed the button twice, and then was able to use the mouse on the laptop. That’s incredibly helpful for slim, premium laptops that have very few ports. This power bank doesn’t have an AC port for full-sized power plugs, as some competing power banks do, but it also costs less and is much smaller than those alternatives typically are.
Setup Process: Easy does it
There’s not much to the setup process here. Using the included USB-C to USB-C cable, simply plug one end into the power bank and the other into an AC adapter that you have handy—like one for a laptop, tablet, or smartphone. Once the four lights on the side are fully illuminated, then the battery pack is fully charged. Simply plug in devices using their respective cables to charge them using the power within the ZMI PowerPack 20000.
Charging Speed and Battery: It keeps going
The ZMI PowerPack 20000 has a hearty 20,000mAh cell within, and it charged my devices quickly without fully depleting the brick. I charged a 2019 MacBook Pro (13-inch) laptop from 0 percent to 100 percent in just 1 hour, 53 minutes using the ZMI PowerPack 20000’s USB-C PD port, with an effective charging rate of 42.92W (14.8Vx2.9A). When the charging process was complete, the PowerPack still had one light illuminated, indicating that there was still a little bit of battery life remaining. In a separate test, I had the ZMI PowerPack 20000 power the MacBook Pro as it played a locally-downloaded movie on loop at full brightness. With the PowerPack plugged in, the laptop maintained its 100 percent charge for 8 hours, 4 minutes before the power bank ran out of juice. The PowerPack 20000 also charged a Samsung Galaxy S10 smartphone from nothing to 100 percent in 1 hour, 47 minutes using the USB-C PD port, with four lights still remaining on the power bank. This sizable power bank should be able to charge an average smartphone a few times over, not to mention a Nintendo Switch. Larger laptop batteries will naturally suck away more of the battery capacity on a full charge.
Price: It’s a bargain
With larger laptop-friendly battery packs sometimes selling for well north of $100, the $70 price point of the ZMI PowerPack 20000 is an incredibly attractive deal. Granted, the maximum USB-C PD output of 45W won’t charge some super-powered laptops—but for compatible laptops, as well as smartphones, tablets, and other portable electronics, it’s very well priced.
ZMI PowerPack 20000 vs Mophie Powerstation AC
It’s honestly difficult to find anything to complain about with the ZMI PowerPack 20000. It’s powerful and does a great job of charging laptops and phones, it has enough capacity to handle those tasks with ease, it’s compact and well-designed, and the price is fantastic. It’s half the size of the giant Anker power brick that I’ve brought on my last two international trips and can handle all of the same tasks. In other words, this is the power brick I’m bringing on my next trip.
