ZMI USB PD Backup Battery

Last updated date: May 14, 2019

DWYM Score
9.4

Why Trust The DWYM Score?

DWYM is your trusted product review source. Along with our in-house experts, our team analyzes thousands of product reviews from the most trusted websites. We then create one easy-to-understand score. Learn more.

Look for the DWYM seal for products that are the best in the category.

We looked at the top 1 Portable Chargers and dug through the reviews from 6 of the most popular review sites including New York Times Wirecutter, iLounge, Switch Chargers, Charger Harbor, Entertainment Buddha and more. Through this analysis, we've determined the best Portable Charger you should buy.

Overall Take

The best thing about the ZMI USB PD Backup Battery is that it supports all of the latest fast-charging protocols, including USB PD 2.0, QC 3.0 and BC 1.2. It also has the power to charge items besides smartphones and tablets, taking on your MacBook or Nintendo Switch console with ease. It does weigh a little more than other portable chargers, but you get three charging ports, with one serving as either an input or output. In our analysis of 59 expert reviews, the ZMI ZMI USB PD Backup Battery placed 1st when we looked at the top 9 products in the category. For the full ranking, see below.

Editor's Note May 21, 2019:
Checkout The Best Portable Charger for a detailed review of all the top portable chargers.

Expert Summarized Score
9.7
6 expert reviews
User Summarized Score
9.0
81 user reviews
Our Favorite Video Reviews
What experts liked
A unique and useful perk is that it can function as a USB hub when connected to a computer’s USB-C port, letting you plug in flash drives, cameras, or even printers to the battery’s USB-A ports.
- New York Times Wirecutter
Although the 20,000 mAh capacity of PowerPack 20000 is impressive, it’s certainly not the first portable battery to pack in that capacity. However, PowerPack 20000 distinguishes itself from many others by offering support for all of the standard fast charge protocols — USB PD 2.0, QC 3.0, BC 1.2 — in both directions.
- iLounge
June 28, 2018 | Full review
The PowerPack 20000 includes a USB-C power cable that handled charging the MacBook and recharging the internal battery pack.
- Macworld
February 9, 2018 | Full review
The ZMI QB820 is a great, large capacity USB-C PD power bank for the Nintendo Switch. It’ll charge the Switch at the fastest possible rate in handheld mode, equal to any wall charger.
- Switch Chargers
What makes using this power bank even better is that it actually goes beyond charging with its two USB-A ports and that’s because once you connect the USB-C port to a laptop, you can use it as a USB Hub.
- Charger Harbor
Looks clearly mean nothing when it comes to a product like this, so in terms of this charger’s abilities to keep your devices charged, it too excels in this era. It features three total USB ports with two of them being USB-A output ports, and the third being a two-way USB-C port.
- Entertainment Buddha
May 11, 2018 | Full review
What experts didn't like
There’s no Lightning cable here, so you’ll need to supply your own if you want to use it with your iPhone or iPad.
- iLounge
June 28, 2018 | Full review
The battery doesn’t come with an adapter, which is a mark against it not on cost, but because it can be tricky to find a good adapter that matches the PowerPack 20000’s wattage.
- Macworld
February 9, 2018 | Full review
My only gripe is the size and weight, but it is no bigger or heavier than any other power bank of similar capacity.
- Switch Chargers
It's quite large and heavy and not really meant for holding and charging your devices.
- Charger Harbor

From The Manufacturer

Since 2014, Zimi Corporation has cumulatively sold over 80 million portable chargers/battery packs worldwide, including our PowerPack line of fast-charging battery packs. The PowerPack 20000 offers more power storage and faster charging speeds than any PowerPack ever. No matter where you go, the PowerPack 20000 will make sure your phone or laptop stays charged. With the PowerPack 20000, you no longer have to constantly search for an open power outlet. You no longer have to be stuck in an awkward position while trying to charge and use your phone at the same time. You can lie comfortably in bed and watch hours of movies on your laptop. Or you can explore the world and always have enough power to stay connected to your friends and family. Whether you are an avid gamer or a business person always on the go, the PowerPack 20000 will ensure you stay charged wherever you go, whenever. Note: When traveling by plane, FAA regulations require you to store your portable charger in your carry-on luggage, NOT checked-in luggage. So there's this growing trend in laptops that only offer one port...we can solve that problem. With the PowerPack 20000, you get 2 devices in 1. Not only a portable charger, the PowerPack 20000 also has a USB Hub mode (USB 2.0 compliant) that delivers data transfer over its USB ports. Need to connect a mouse to your laptop? Plug it into the PowerPack 20000. Need to access an external flash drive? Plug it in. Need to connect a gaming controller? Plug it in. In addition, the USB Hub mode is perfect for powering your smaller devices that will require a smaller charging current. These may include smart watches, Bluetooth headphones, fitness trackers, and other wearables. With these features, you can create a portable office (or gaming center), so you can get some serious work done wherever you go.

Overall Product Rankings

1. ZMI USB PD Backup Battery
Overall Score: 9.4
Expert Reviews: 6
2. Anker PowerCore+ Portable Charger
Overall Score: 8.8
Expert Reviews: 5
3. Jackery Supercharge Portable Charger
Overall Score: 8.6
Expert Reviews: 3
4. Jackery Portable Charger Bar
Overall Score: 8.5
Expert Reviews: 6
5. RAVPower 10000mAh Portable Charger
Overall Score: 8.4
Expert Reviews: 3
6. AUKEY Power Delivery Power Bank
Overall Score: 8.3
Expert Reviews: 4
7. Intocircuit Portable External Charger
Overall Score: 8.0
Expert Reviews: 9
8. Anker PowerCore+ Mini Portable Charger
Overall Score: 8.0
Expert Reviews: 11
9. RAVPower Portable Charger
Overall Score: 7.3
Expert Reviews: 3

An Overview On Portable Chargers

There’s no shortage of portable chargers available. In fact, once you start shopping, you’ll likely immediately be aware of the vast array of products out there. But although portable chargers may look alike, some even promising very similar specifications, there are notable differences from one product to the next.

One of the biggest features to look at when shopping for a portable charger is how long it will take to charge your devices. This is especially important if you have a device with fast-charging capabilities since not all portable chargers support that. A device that can fully charge multiple items at once in a limited amount of time may be well worth paying extra or sacrificing other features, such as portability.

Another feature that sets some newer chargers apart from others is the ability to charge more than just a smartphone or tablet. Some of these devices can charge a laptop or gaming console, making them useful if you’re regularly out and about with these items. You’ll also find some chargers can plug into your computer and act as a hub, charging multiple devices at once while you’re working.

While all portable chargers are designed to tuck into backpacks and laptop bags, some are even more powerful. If it’s important to be able to slip your charger into a pocket or handbag, look for much smaller devices. Some are only slightly larger than a tube of lipstick, making them especially portable, but you may sacrifice power and charging capabilities for that convenience.

While you’re waiting for your devices to charge, you may occasionally want to check in on status. Some chargers have indicator lights that show you exactly where you are in the process, giving you a general idea of the time you have left. However, if you’re only charging smartphones and laptops, you’ll likely be able to get this same information by looking at the device itself.

DYWM Fun Fact

USB-C is poised to revolutionize the way devices are charged. Instead of having multiple ports on a device for all the different cables you need, with a USB-C, you can use the same port as both an input and an output. This can be seen on newer equipment like MacBooks. You can either plug your power cord or your USB charging cord into any of the ports provided, aside from the headphone jack, but even that is changing. Some phones replace the headphone jack with a USB-C port, although you’ll still find the traditional 3.5mm headphone jack on laptops. The goal with USB-C is not only to streamline the ports that devices need to have but also to provide a single standard that will make life easier for everyone.

The Portable Charger Buying Guide

  • A good portable charger starts with its power. The Anker PowerCore+ Portable Charger and Jackery Supercharge Portable Charger pack the biggest punches, with 26800mAh of power each. You’ll still get impressive power in the ZMI USB PD Backup Battery, which has 20000mAh capacity. The much smaller Anker PowerCore+ Mini Portable Charger lags behind, with only 3350mAh.
  • The time it takes to charge is a top consideration. Although this can vary depending on the capacity of each device you’re charging,  the Anker PowerCore+ Portable Charger generally excels at this, with the ability to charge three devices at once at a lightning-fast speed.
  • Before you can charge other items, you’ll need to charge the portable charging device. The Anker PowerCore+ Portable Charger can charge faster than other power banks, reaching full capacity in about 6.5 hours. The Anker PowerCore+ Mini Portable Charger also falls behind in this area, taking approximately three hours to fully recharge after depletion.
  • One factor determining how quickly your portable charger can get results is whether or not it supports the new fast-charging capabilities built into many modern devices. The ZMI USB PD Backup Battery stands out from the pack here, supporting all the current protocols, including USB PD 2.0, QC 3.0 and BC 1.2. The Anker PowerCore+ Portable Charger can’t compete in this area, lacking the ability to charge devices like the iPhone X or iPhone 8 at the fastest available speed.
  • New charging technologies built into devices like laptops and gaming consoles make it easier to build portable chargers for them. The ZMI USB PD Backup Battery can not only charge your smartphone but it also capably charges the newer MacBooks that have Thunderbolt ports, as well as being able to charge the Nintendo Switch at the fastest possible rate in handheld mode. The Jackery Supercharge Portable Charger can also charge both MacBooks and Nintendo Switch consoles. The Anker PowerCore+ Mini Portable Charger is very limited in what it can charge, lacking the power necessary to handle most tablets. You’ll also find it can’t charge the latest Android phones, which have higher-capacity batteries.
  • One of the best things about the ZMI USB PD Backup Battery is its ability to serve as a hub. Simply plug it into a computer’s USB-C port, then plug your items into the two USB-A ports to charge while you work.
  • If you’re concerned about portability, look closely at the weight and size of the devices you’re considering. The Anker PowerCore+ Mini Portable Charger is among the lightest portable chargers you’ll find, weighing only 2.8 ounces. Compare this to the 15.16 ounces you’ll get with the Jackery Supercharge Portable Charger, and you can see the difference. Both the ZMI USB PD Backup Battery and Anker PowerCore+ Portable Charger are on the higher end of weight, at 14.25 and 13.5 ounces respectively.
  • The Anker PowerCore+ Mini Portable Charger is also far easier to slip into a pocket, measuring only 3.5 inches long and 0.9 inches thick. The ZMI USB PD Backup Battery, Anker PowerCore+ Portable Charger and Jackery Supercharge Portable Charger all have longer, slimmer profiles, similar in shape to a smartphone. They each measure around 6 inches by 3 inches, meaning they’ll still easily slip into a laptop bag or purse, but they may not be quite as easy to carry around all day with you.
  • Portability comes at a price, however. With the Anker PowerCore+ Mini Portable Charger, you can charge only one device at a time. The Anker PowerCore+ Portable Charger, on the other hand, has three powerful output ports. With the ZMI USB PD Backup Battery, you also get three charging ports. That includes a USB-C input and output port, which means you can either use it to charge a device or accept a charge. The Jackery Supercharge Portable Charger has only two ports, a USB-C and a USB-A.