You’re trying to decide between two phone chargers, one rated at 5 watts, and another rated at 10.
Seems like an easy decision. Take the more powerful charger because it’ll fill your phone’s battery faster, right?
Not necessarily. The charger is only half the equation. Your phone also has a say in how much power it can receive. That’s an important distinction for a couple of reasons. Knowing your phone’s charging specs will help find a charger that tops off your battery the fastest without paying for more power than you need.
Why your phone matters just as much as your charger
In general, the higher the wattage a phone receives, the faster it charges. But phones have a maximum wattage they’ll accept. That means that if you use a charger that delivers 10 watts with a phone that only accepts 5 watts, it’ll still only charge at 5 watts. Nothing bad happens when using the more powerful charger; it’s just more than you need.
Let’s look at a real world example:
The iPhone 7 comes with a 5-watt charger, but it is capable of accepting 12 watts of power. Charging at the phone’s full capacity with Ventev’s wallport r430, which delivers 15 watts, shaves 30 minutes off of the iPhone 7’s charge time, and 90 minutes off the iPhone 7 Plus’s charge time.
But even though the r430 is capable of charging at 15 watts, the iPhone 7 only charged at 12 watts. Again, the phone dictates the current it receives.
Other aspects of charging to keep in mind
There are some other ways in which the phone controls charge time. Have you ever noticed when filling a nearly depleted phone that the battery fills faster at first, and then slows down? That, too, is dictated by the phone. To prevent a battery from overheating or overcharging, the phone charges at a fairly constant rate until it gets to about 90 percent. Then it slows down, letting the charge trickle in. Think of it like filling a glass of water. At first, you pour the liquid rapidly, but as it gets close to the top, you ease off to prevent spillage.
Lastly, if you have a phone that uses Qualcomm Quick Charge, look for chargers that support that technology. That technology optimizes battery charging to make it efficient and fast, but Qualcomm’s technology is proprietary. If you use a charger that doesn’t support it, your phone won’t hit its optimal charging time.
What to do next
If you’re looking for a phone charger, know how much power your phone can accept, and whether it uses a specific technology, whether Qualcomm Quick Charge or USB-C Power Delivery, like the Google Pixel and Pixel XL. Find a charger that matches the speeds your phone will allow. If you do a little research on the internet, you might even be able to find a charger that’s more powerful than the one that came with your phone.
If you do end up with a charger that delivers more power than your phone accepts, just don’t expect it to get you to 100 percent any faster – your phone sets a speed limit the charger can’t exceed.