You might not think about what you plug your phone, tablet, or laptop into as much as you do finding something to give it power. After all, once your device is on the charger, it’s not going to die, and that’s really the main thing. But not all chargers are created equal; if you’re in the habit of plugging your devices into whatever port or outlet is most easily within reach, those devices might be charging much slower than they need to be.
A quick breakdown about chargers
Chargers usually have two parts; the cable, and the power adaptor. The power adaptor is what many of us call the charging “brick,” and it plugs into your outlet, and the cable obviously connects the power adaptor to your device. Sometimes, you can charge without a power adaptor, if you plug one device into another, such as a computer, or into an outlet with a USB port. In the case of wireless charging, the charging pad acts as the cable.
The cable typically doesn’t matter for charging speeds; what really matters is that power adaptor. Some adapters are more powerful than others, capable of delivering more charge to a device than their smaller counterparts. We measure this power in watts (W). If you take a look at your power adapters, you’ll likely see their rating somewhere on the device; 5W, 18W, 30W, etc.
We’re also not talking about proprietary chargers, either. If your device only chargers with a specific charger, that’s what you’re going to use. We’re talking about mostly USB devices, which can be versatile with the cables and power adapters used for charging.
It’s not easy to know which charger to use
With all these different power adapters, it’s not always obvious which one is best for your device. Some devices aren’t making things any easier, either, particularly smartphones. Apple set a recent standard of omitting a power adaptor with its latest iPhones, a standard other smartphone OEMs are also following. While the company says this decision is fuelled by environmental concerns, it leaves the consumer without a power adaptor to charge their device. It also leaves the consumer without an idea of what power adaptor they should use for their device.
Not that Apple was much help in the past, though. For years, Apple included a measly 5W power adaptor with its iPhones. This power adaptor might be the one you still use to charge your iPhone. It’s a shame, too, because that 5W charger fuels your iPhone slowly.
Why it’s important to know your limits
All devices have a peak current they can draw from a power adaptor. It’s fine to plug those devices into a larger power source than they’re rated for, as the device will only draw the maximum current it’s rated for. If a phone is only rated for 27W, and you plug it into a 35W charger, for example, that phone is still going to top off at 27W. It’s not dangerous.
You can also plug devices into power sources that are lower than those devices are rated for, which brings us back to the iPhone example. Apple introduced fast charging with the iPhone 8, 8 Plus, and X, rated at 15W. The power adaptor, however, was 5W. You could safely use that power adaptor to slowly juice up your phone, but you’d need to buy a power adaptor with at least 15W to take advantage of the full charging speeds.
The best thing to do is to look up your device’s specs. My iPhone 8 Plus, for example, is capable of taking in 15W of power. So, if I plug it into a 12W power adaptor, I’m not taking full advantage of its charging capabilities. If I plug it into an 18W power adaptor, then I know my phone will charge as fast as possible. The Galaxy Tab 7+, on the other hand, is rated at 45W fast charging. You’ll want to use a power adaptor with this wattage or higher in order to max out charging speeds. Anything lower will take longer to charge.
This information can be hard to come across sometimes, however. In the event of laptops, like a MacBook, you’re best served by going off of the charging brick that comes with the machine. The M1 MacBook Air, for example, comes with a 30W power adaptor. You can deliver power to it with a smaller USB-C charger, but it’ll charge slowly — and it might actually lose power if you’re actively using the computer. Using a larger power adaptor, however, will work fine, as the computer won’t take in more than it can handle.
In short, bigger power adapters are usually better. You won’t hurt your device, and you’ll have a better chance of charging it as fast as it can go.
Wireless chargers are a bit of an exception
Wireless charging, while convenient, is a fundamentally slower charging technology than the traditional cable-to-power adaptor. You need to buy the right wireless charger to take advantage of the fastest speeds (if your phone can even handle them), and, even then, they aren’t fast.
Unfortunately, you can’t throw a bigger power adaptor at a wireless charger and expect it to keep charging faster than its peak. They’re a bit like the devices themselves in this way; once they hit their peak, there’s nowhere else to go.