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You need a portable battery with high-speed charging capability.
But not all portable batteries are the same, despite the fact that they might use similar Lithium Polymer (LiPo) and Lithium Ion (Lion) cells for capacity and look very much alike.
There are three different high-speed USB charging standards currently on the market, and while all of them will work with your device using a common legacy charge mode, you will ideally want to match up the correct technology in order to optimize the speed in which you can top off your phone, tablet, or laptop.
Let's start by explaining the differences between them.
Legacy USB-A 2.0 and 3.0 charging
If your smartphone device has the USB Micro B connector (the dreaded fragile trapezoid that's impossible to connect in the dark) you can fast charge it using an inexpensive USB-A to USB Micro B cable.
If the device and the charge port both support the USB 2.0 standard (pretty much the least common denominator these days for entry-level Android smartphones) you can charge it at 1.5A/5V.
Some consumer electronics, such as higher-end vape batteries that use the Evolv DNA chipset can charge at 2A.
A USB 3.0/3.1 charge port on one of these batteries can supply 3.0A/5V if the device supports it.
If you are charging an accessory, such as an inexpensive pair of wireless earbuds or another Bluetooth device, and it doesn't support either of the USB-A fast charging specs, it will slow charge at either 500mA or 900mA which is about the same you can expect from directly connecting it to most PCs.
|USB PD||Variable up to 20V||5A||USB-C|
|USB Type-C 3A||5V||3.0A||USB-C|
|USB Type-C 1.5A||5V||1.5A||USB-C|
|QC 4.0 (USB-PD Compatible)||Variable up to 20V||4.6A||USB-C|
|QC 3.0||Variable up to 20V||4.6A||USB-A/USB-C|
|QC 2.0||5V, 9V, 12V, 20V||2A||USB-A|
|USB BC 1.2||5V||1.5A||USB-A|
Many of the portable batteries on the market have both USB-C and multiple USB-A ports. Some of them have USB-A ports which can deliver the same voltage, while others feature one fast (2.4A) and one slow (1A).
So you will want to make sure you plug the device into the battery port which can charge it the fastest rate if you want to top the device off as quickly as possible.
USB Power Delivery
USB Power Delivery (USB PD) is a relatively new fast charge standard which was introduced by the USB Implementers Forum, the creators of the USB standard.
It is an industry-standard open specification that provides high-speed charging with variable voltage up to 20V using intelligent device negotiation up to 5A at 100W.
It scales all the way up from smartphones to notebook computers provided they use a USB-C connector and a USB-C power controller on the client and host.
Batteries which employ USB PD have the ability to charge devices up to 30W output using a USB-C connector.
Apple introduced USB PD charging with iOS devices with the launch of the 2015 iPad Pro 12.9" and with OS X laptops in the MacBook Pro as of 2016.
Both the iPhone 8 and the iPhone X can rapid charge with USB PD using any USB PD charging accessory, but it requires that you use Apple's OEM MKQ42AM/A (1m ) or MD818ZM/A (2m) USB-C to Lightning cables which unfortunately are a tad expensive at around $19-35 from various online retailers.
There are cheaper 3rd-party USB-C to Lightning cables, but none of the ones we have tested currently on the market will charge current generation iOS devices at full speed -- they can't do better than 2.4A because Apple uses a special integrated circuit in their cables for power negotiation.
Qualcomm Quick Charge
Qualcomm, whose Snapdragon SoCs are used in a number of popular smartphones and tablets, has its own fast-charging standard, Quick Charge, which has been through multiple iterations.
The current implementation is Quick Charge 4.0 which is backward-compatible with older Quick Charge accessories and devices. Unlike USB PD, Quick Charge 2.0 and 3.0 can be delivered using the USB-A connector. Quick Charge 4.0 is exclusive to USB-C.
Quick Charge 4.0 is only present in phones which use the Qualcomm Snapdragon 835 (and the forthcoming Snapdragon 845) which can be found in the US version of the Samsung Galaxy S8/S8+/Galaxy Note 8, OnePlus 5, HTC U11, LG V30, Moto Z2 Force, Essential PH-1 and also the Google Pixel 2/XL.
The Xiaomi Mi 6, Xiaomi Mix 2, ZTE Nubia Z17, and the Sony Xperia XZ Premium also use QC 4.0, but they aren't sold in the US market currently.
Like USB PD, QC 3.0 and QC 4.0 are variable voltage technologies and will intelligently ramp up your device for optimal charging speeds and safety. However, Quick Charge 3.0 and 4.0 differ from USB PD in that it has some additional features for thermal management and voltage stepping with the Snapdragon 820/821/835/845 in order to optimize for reduced heat footprint while charging.
It also uses a different variable voltage selection and negotiation protocol than USB PD which Qualcomm advertises as better/safer for its own SoCs.
And for devices which use Qualcomm's current chipsets, Quick Charge 4.0 is about 25 percent faster than Quick Charge 3.0. The company advertises five hours of usage time on the device for five minutes of charge time.
However, while it is present in (some of ) the wall chargers that ship with the devices themselves, Quick Charge 4 is not in any battery products yet. The reason for this is that it is not just competing with USB Power Delivery, is also compatible with USB Power Delivery.
Qualcomm's technology and ICs have to be licensed at considerable additional expense to the OEMs, whereas USB PD is an open standard.
If you compound this with the fact that Google itself is recommending OEMs conform to USB-PD over Quick Charge for Android-based products, it sounds like USB-PD is the way to go, right?
Well, sort of. If you have a Quick Charge 3.0 device, definitely get a Quick Charge 3.0 battery. But if you have a Quick Charge 4.0 device or an iOS device, get at USB PD battery, for now.
Now that you understand the fundamental charging technologies, which battery to buy?
|Vendor||Model||Tech|| Capacity |
|Port 1||Port 2||Port 3||Port 4||MSRP|
|RavPower||RP-PB058||USB PD||26800||USB-A||USB-A||USB-C (30W)||USB-Micro-B (Input)||$79.99|
|Anker||PowerCore+ 26800 PD*||USB PD||26800||USB-A||USB-A||USB-C (30W)||*||$119.99|
|RavPower||RP-PB043||QC 3.0||20100||USB-A||USB-A (QC 3.0)||USB-C (18W)||USB-Micro-B (Input)||$49.99|
|RavPower||RP-PB059||USB PD||20100||USB-A||USB-A||USB-C (30W)||USB-Micro-B (Input)||$69.99|
|Anker||PowerCore Speed 20000 PD*||USB PD||20100||USB-A||USB-C (30W)||*||*||$99.00|
|Anker||PowerCore II 20000||QC 3.0||20000||USB-A (18W)||USB-A (18W)||*||*||$49.99|
|Mophie||Powerstation USB-C XXL||USB PD||19500||USB-A||USB-C (30W)||*||*||$149.95|
|Belkin||Pocket Power 15K||USB 3||15000||USB-A||USB-A||USB-Micro-B (Input)||*||$49.99|
|Mophie||Powerstation Plus XL||USB PD||12000||USB-A (15W)||USB-C (18W)||*||*||$99|
|Belkin||MIXIT Power RockStar 10000||USB 3||10000||USB-A||USB-A||USB-Micro-B (Input)||*||$49.99|
* Two Anker models -- PowerCore+ 26800 PD and PowerCore Speed 20000 PD -- are the only two models to include a wall charger.
We've tested a bunch of these and we've essentially narrowed it down to two: The RAVPower RP-PB058 for USB PD (newest iPhones and newest Androids) and the Anker PowerCore+ 26800 for Quick Charge 3.0 (Previous generation Androids). Both are 26800mAh batteries with huge charge capacity.
Anker's product is more expensive but it comes with a USB-C QC 3.0 wall charger that can be used with the battery or direct charge a QC 3.0 compatible device, whereas the RAVPower we have seen on the street as low as $60 with wide market availability and with Amazon Prime promotions, so be sure to shop around because that is a great value at that price.
Anker also has a USB PD version of the PowerCore+ 26800 bundle but it is not as easy to find. We suspect the company is working on a new product revision compatible with USB PD and QC 4.0 and it will be out after the holidays -- but if you see the current model on sale, jump on it. We particularly like the metal case design and the large illuminated power stud button that is easy to feel even in the dark.
Both of these companies sell equivalent USB PD and QC 3.0 products. However, because of licensing, the QC 3.0 ones appear to be priced more expensively -- so unless you have a QC 3.0 compatible device, we suggest you stay with USB PD charging accessories for now.
A product that we did not mention in earlier drafts of this article is the ZMI 20000 mAh USB PD Backup Battery which along with its USB PD wall charger is currently on promotion at Amazon. If you buy both of these products together, Amazon will apply a $12.98 promotional discount, which makes the combined price $97.92.
This particular product has the distinction of having both USB PD and QC 3.0 capabilities, has a 45W USB PD output, and can also act as a daisy-chained USB 2.0 hub, so it is a particularly good buy.
The Belkin features a unique product design with a metal casing which integrates a magnetic storage sleeve for their included heavy-duty Lightning and USB-C cables, so it's ready to go and there's no fumbling around for wires in your bag.
However, it only does up to 4.8A charging shared between its two USB-A ports (2.4A per port). It can't do USB PD or QC 3.0. We're hoping that the company updates the product soon for USB PD because it's the nicest looking battery we've seen to date.
The Mophie is also a very nice looking battery as it integrates a fabric wrap over the polycarbonate casing so it's pleasant to the touch -- and it fully supports USB PD at 30W.
However, it only has a single USB-A port and it's considerably more expensive than Anker or RAVPower's equivalent products at $150. We expect that they will eventually drop the price on it so that it's more in line with its 20,000mAh competitors.