USB Type-C (or USB-C) had its coming-out party quite late—at this year’s CES in early January, even though the connection type made its broad debut with Apple’s 12-inch MacBook in April 2015. Since then, more devices have adopted the format, such as the Chrome Pixel C and Nexus 6P. (The new Apple TV has a USB-C port but only as a connection option for debugging and making screen captures with a Mac.) An ocean of USB-C devices is coming that will include more Macs as part of the Thunderbolt 3 update—which relies on that connector style—and possibly some iOS hardware.
I’ve been waiting to test USB portable batteries equipped with USB-C since the MacBook shipped. But as long as Apple relied on the MagSafe connector, you couldn’t get a licensed and certified adapter that would work with a Mac laptop. USB-C changes that altogether. It has bi-drectional power support, allowing energy to flow from a laptop or other controller’s USB-C to charge or power external devices and via USB-C to charge a MacBook or similar device’s internal battery.
In general, USB battery packs used to have limited capacity, offer slow charging of devices and recharge slowly, and cost and weigh a lot relative to the benefit they offer. But they’ve matured very rapidly over the last few years. With the very large-scale manufacture of standard-sized rechargeable lithium-ion battery cells, electronics makers have created affordable, high-capacity USB packs that range from recharging your iPhone 6s by about 50 percent up to the equivalent of a week’s worth of multiple full recharges of a set of iPads and iPhones.
Laptops have typically been in a different category, because they not only have large batteries, but when in use, they draw power faster than previous USB packs typically provide it because of limitation in the previous generation of USB connector and cable standards. In such a case, a Mac laptop pulls juice from the USB-connected battery, but also gradually runs down its internal one.
The iPad Pro suffers from this problem. It ships with a 12-watt power adapter that can’t always keep up with power consumed while you’re using the iPad Pro. While its battery could safely be charged at a much higher wattage (at least twice as “fast” in terms of power flow), the Lightning standard appears to limit its maximum rate.
USB-C breaks through that limit by allowing higher-amperage charging even though USB has a set limit on voltage. (Wattage is the product of amps times volts, representing the total energy transferred.) This higher amperage can allow a USB battery pack to recharge a 12-inch MacBook relatively speedy when put to sleep, although the units I tested still can’t keep up with its power consumption.
Sign up for CIO Asia eNewsletters.