 One thing I've noticed as a reviewer at The Verge is the problem surrounding smartphone batteries. Regardless of which next-gen battery technology you're using, lithium-ion batteries tend to just die during the day anyways. If science can't come up with better battery technology, it can at least change how quickly we charge our batteries. USB-C for Android phones and the lightning cable for iPhones are now capable of delivering hours of battery life with minutes of charging. It makes life easier if you're running to meetings and don't want to carry around battery packs. But just how fast can we charge our phones? Not just presently, but how fast can fast charging get in the future? So before we get into fast charging, let's take a refresher course. Volts, amps, and watts. Let's look at it like this. Volts represent the amount of electricity available in your wall outlet. The current, or amperage, is controlled using your charging brick, and is the rate at which the electricity travels. And finally, the watts are the total electrical power that gets into your phone. This means that watts are the products of volts and amps. Volts times amps equals watts. In order to charge our battery, we can increase the volts and charge it faster. If we increase the amperage, we could also charge the battery faster. And if we increase both, we can drastically increase the power going into the battery. The thing you need to remember about any energy transfer is resistance, the byproduct of which is heat. Excessive heat for batteries, as we know, is really, really bad. Historically, most USB chargers range from 5 to 12 watts, but they weren't able to charge fast and stay cool. Today, USB-C has come a long way. It supports up to 100 watts, charging time set by the manufacturers, and supports a wide variety of devices. To make sure that the battery doesn't overheat, OEMs like Qualcomm and Apple install devices called charge controllers. They regulate electricity going into the device and make sure that they don't overvolt or overcharge, and thus keep the battery safe and cool. For example, if I use a 100 watt power brick to charge my MacBook Pro, it'll use the full 100 watts. That's what it's supposed to do. But then, if I put that same charger into my phone, the charge controller will transfer the most power it can use before it damages the battery, around 29 watts or so. All fast charging standards, like OnePlus's Dash Charge, Apple's Fast Charge, or Qualcomm's Quick Charge, basically do the same thing. They charge your battery safely, quickly, and they make sure that it doesn't overheat, while it's doing so. Okay, so what's fast charging performance like nowadays? Well, the fastest way to charge your phone is with the cables out of the box. Android phones like Galaxies, Pixels, OnePlus devices, or LG phones should come with fast charger setups. But with Apple, you'll need to buy a USB power delivery brick and USB-C to lightning cable. That will allow you to charge an iPhone X from 0 to 50% in 30 minutes. That's pretty good, but what sort of performance improvement are we going to see in the next couple years? Unfortunately, not much. There is one concept that could allow us to charge our phones in a matter of seconds, and it's called a supercapacitor. Electrons make an electrical field, which allows them to travel much faster. The problem is, though, again, overheating. But that's all theoretical. Back to reality. Qualcomm is working on the next fast charging tech called Quick Charge 4+. It's actually available on a couple phones right now, but not many. Quick Charge 4+, aims to not only regulate heat better, from the conductors, but also charge the phone even faster. In fact, Qualcomm designed a reference smartphone, which can charge from 0 to 50% in just 15 minutes, which is pretty fast. Your next flagship smartphone is probably going to be using Quick Charge 4+, and get closer to those numbers. And while those numbers aren't instant, well, at least your phone won't blow up. Thanks for watching. And remember not to use off-brand or cheap cables for fast charging, because they can really mess up your phone and your battery. And if you want to hear more about batteries, head on over to Verge Science.