From coolers to cars, USB ports are popping up in places you might not expect. While many of these products promise convenient on-the-go charging, it’s tough to tell which ports will give you the most power. And since most of us are tethered to desks all day, charging your phone through your computer’s USB port seems like an easy option.
Until you look at the numbers. Your computer is actually one of the least efficient ways to power up your mobile device. Most laptops and desktops only deliver a 0.5 amp charge to your phone – less than half of a typical phone’s 1-1.5 amp charging capacity. That means charging takes twice as long.
And if you have a Qualcomm Quick Charge 2.0 or Adaptive Fast Charging device that can accept more volts for a faster charge, powering up with your computer means even worse performance. The situation doesn’t change if your laptop is plugged in, either; the maximum charging rate will always be a lackadaisical 0.5 amp.
Of course, there has to be one exception to the rule. Some recently released computers with new USB ports have the updated charging circuitry required to deliver higher amperage for faster device charging. But this is only possible with newer models, so unless you’ve recently upgraded your laptop or computer, it’s likely you’ll only get the 0.5 amp charge.
What about plugging your phone into your car? Most new models have both USB ports and power outlets, so either should be useful for charging, right?
Plugging into your car’s USB port won’t give you any better charge than you’d get from a laptop or desktop (although we might see this change with newer model cars). The reason is the same: You’re still basically connecting to a computer. In a vehicle, the computer is the “infotainment center” — apps like navigation, Bluetooth, satellite radio, Wi-Fi. The USB ports will still only provide that slow-moving 0.5 amp charge, even in the fastest sports car.
All the USB ports in both computers and cars were designed for data transfer. The fastest and best way to charge your devices is to plug them into a wall charger (wallport), car (dashport) charger, or portable battery pack (powercell) that matches your phone’s charging ability. Taking a few seconds to plug into a dedicated power source will give you more power in less time.