If you need to charge higher capacity devices like a laptop, ZMI’s PowerPack 20K Pro should work with most USB-C laptops through its 65W USB-C port, according to the brand. It measures its capacity at 20,000mAh or 72Wh. It can also double as a USB hub, so you can plug flash drives into it while you’re charging your laptop.
If you want to charge your laptop faster, you’ll want an even more powerful battery bank. Goal Zero’s Sherpa series, made with a tough aluminum build, has a 60W USB-C port as well as two 2.4A USB ports, according to the brand. It has a 94.7Wh capacity — just about the highest that you can legally bring on a plane. It also sports a wireless charging pad that lets you charge your device without cables and you can use its USB ports to charge multiple devices simultaneously.
Grudo said he’s gifted the compact Anker PowerCore Fusion III to several family members — “it’s great for commuting — you can both plug it into the wall and take it with you,” he said. While it does have the lowest capacity on this list at 5,000mAh, it also has the smallest dimensions and equips both a 12W USB-A port and an 18W USB-C port.
When shopping for a portable charger, you’ll most likely need to balance size and capacity — you want something that fits comfortably in your backpack or purse, but you also want something that can charge your devices as much as possible.
Charging capacity is often measured in either milliamp hours (mAh) or watt-hours (Wh), according to our past reporting.
While phone manufacturers lean into mAh as a spec, “watt-hours is a better, more accurate rating of capacity,” explained Brad Saunders, chairman of the nonprofit USB-IF. If your battery pack uses Wh, you can compare the watt-hours on the battery pack to the number of watt-hours held by the device you want to charge. For example, a 12Wh battery could fully charge a 4Wh device three times.
Keep in mind that physically larger devices usually have bigger batteries. Plus-sized phones and tablets will need more juice to get to 100 percent compared to their smaller siblings. Ultimately, you’ll need to balance your charging needs with how much space you have to lug a battery bank around.
Just about any battery pack will charge your phone, but some can do it faster than others by using different fast-charging standards. USB ports are typically anywhere from 1Amp up to 2.4Amps — the higher the amps, the faster your device will charge. (Belkin’s portable charging guide goes into more detail about this.)
Some phones will come with proprietary Quick Charge (QC) tech, either using Qualcomm Quick Charge or their own branding, like Samsung’s Adaptive Fast Charging or Motorola’s TurboPower. Sometimes you’ll see Quick Charge-branded USB ports on battery packs — if your phone is compatible, it’ll charge even faster through that port.
Many modern devices use a simpler USB Power Delivery (PD) standard, which means they will charge as fast as they can with whatever PD-compatible charger or battery bank you plug them into. USB PD chargers work with your device to determine the optimal charging power up to 100W in order to charge it as quickly as possible.
We previously recommended buying a newer PD-compatible battery bank if you’re looking for fast charging since it’s the easiest to understand — it measures charging speed in watts and is more widely supported by modern tech companies. You can see which fast-charging standards your phone supports by checking its page on the manufacturer’s website.
Choosing the right battery pack is just a matter of comparing its wattage to your device’s charger. “If it says ‘works best with a charger that’s rated at 27W and higher,’ then go look for the 27W-and-higher charger,” Saunders said. In most cases, your device will still work with a lower wattage charger, though it’ll charge more slowly.
While phones and tablets don’t need too much power to charge, laptops might have higher requirements and will need a high-capacity battery pack — you’ll often find laptops measured in the more accurate Wh, in addition to or in lieu of mAh. You’ll want to make sure you get a battery pack that matches or exceeds that number.
Our experts also suggested looking at certain features to determine the best portable charger for you:
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