What Is ‘USB Fast Charging’ and Why Does It Matter for Your Smartphone?


What’s the Best Way to Charge Your iPhone?

We won’t go over every single charger type and charging method that ever existed, but we will go over the ones people ask the most questions about, plus the ones you should know about in order to keep your device battery in good health. Click a link below to navigate directly to the section you’re looking for, or scroll through to learn about each in order. You’ll be able to return to this list by clicking “return to top” throughout the article.

What to Know About Chargers & Cables

Other iPhone Charging FAQs

Can USB 3.0 be used for charging?

You can also charge your devices faster with a USB 3.0 connection. In fact, a USB 3.0 charger can deliver almost double the output of a USB 2.0 charger. While USB 2.0 caps out at around 0.5 Amps, a USB 3.0 charger can deliver around 0.9 A of power.


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Why do some USB-C cables charge slowly?

It’s likely to be one of three problems (or a combination of them): You could be using the wrong kind of power outlet, the wrong kind of wall plug, or the wrong kind of USB cable. In each case, the slow charging has to do with amps: The rate at which electrons are flowing into your gadget.

Does your cable really affect how fast your phone charges?

With the exception of color and size, cables tend to look the same. Yes, one might be lightning and yes, one might be USB, but otherwise there isn’t much difference. Right?

Wrong. And it’s all for a beautiful reason – it’s what’s on the inside that counts!

What Is Wireless Fast Charging?

Wireless charging is convenient, but it can be slow. Most wireless chargers that lack fans or cooling systems are limited to charging speeds of just 5V/1A. But various companies now offer fast wireless charging pads that come with built-in fans to dissipate heat, allowing you to charge at speeds nearly on par with a cable.

Voltage and amperage depend on the charging pad in question. Once again, you’ll want to make sure that your phone and your wireless charging pad support the same fast charging standard. Also keep in mind you’ll need a wall adapter plugged into the pad that supports fast charging as well.

There are lots of variables to think about when buying a wireless charger, so we’ve done the homework for you by creating a list of the best wireless charging pads based on your phone and budget. 

What Will Damage Your Phone Battery?

So, if it isn’t the fault of your charger, what is making your battery degrade? Several factors can impact the life of your battery, and this goes for most batteries, not just the one inside your phone. Let’s break them down.

Letting Your Battery Discharge All the Way or Stay Charged All the Way

Batteries don’t like extremes. Don’t let your batt

Batteries don’t like extremes. Don’t let your battery discharge all the way down on a regular basis, but don’t let your battery stay at 100% all the time either. When a battery is fully charged or fully discharged, all of its movable lithium ions are on a single layer, which puts a strain on the battery. Even a small amount of strain on a battery will cause the battery to degrade faster than necessary.

The Fix: According to Wired, you should try to keep your phone charged between 20% and 80%, and the most optimal charge is 50% for the best outcomes. You don’t need to go crazy with this, but it will help extend your battery’s life.

Keeping Your Phone in High Temperatures

One of the worst things you can do for your phone battery is to store your phone in a high heat environment, like leaving it in your car in warm weather or in the full sun on your deck.

According to the Center for Disease Control, the heat of a car can rise by 20 degreed Fahrenheit in 10 minutes, and more if you leave it to sit longer. This means that on an 80-degree day, your phone could be in 100-degree temperatures within ten minutes!

High heat will damage your battery over time and reduce its life, and you might not even be able to tell your battery is damaged until it stops working completely, or, at worst, becomes so damaged that it explodes.

The Fix: Don’t leave your phone in direct sun or in your car, especially if it is charging, which can already increase the temperature of your battery. Instead, carry it with you and keep it in a bag or your pocket. This will also help prevent it from getting stolen while unattended.

Using Cheap, Generic Chargers

All cheap, generic, low-quality electronics, including phone chargers and batteries, should be avoided at all costs. A quick scroll through the reviews on these products reveals how unsafe they are. You’ll find stories of fires, explosions, and electric shocks. It doesn’t paint a pretty picture.

It might cost a little more, but a brand name charger will be more reliable, last longer, and be safer than these shoddy products.

The Fix: Purchase all phone charging equipment from a trusted source. Beware of “name brand” products on discount websites that are knock offs.

Damage to Your Phone

Any physical damage to the phone can also cause your battery to become damaged. If the battery’s hardware becomes damaged. Twisting and bending on the phone can cause problems, but even a bad fall can knock something out of place inside the phone.

Water damage can also cause problems for your battery, usually in the form of corrosion forming around the sensitive parts of your phone. Thankfully many phones being made nowadays are waterproof or water-resistant.

The Fix: Keep your phone in a shock-absorbent case and be careful with your phone in areas where it may come in contact with water, including in the bathroom, kitchen, or while swimming.

Leaving Your Phone on the Charger Overnight

Like we mentioned above, a phone shouldn’t stay at 100% for too long because it puts more wear and tear on the phone. Don’t leave your phone on its charger for long periods of time, like while you sleep. 

The Fix: Charge your phone during times when you can monitor its progress. Unplug as soon as you notice it is at 100%. If charging your phone at night is important to you, you could use a timer to turn off your phone’s charge in the middle of the night.

What is USB Power Delivery?

We all know that we can charge some of our devices via USB, but what is USB-C Power Delivery, exactly? Read this brief guide on how Power Delivery works.

Volts and amps

Voltage and amperage are confusing concepts. An admittedly over-simplified1 metaphor looks like this:

Consider a squirt gun – typically a plastic toy that you fill with water. To use it, you squeeze a trigger to shoot the water out of the gun.

  • Voltage is akin to the size of the hole that the water comes out of.
  • Amperage is analogous to how hard you pull the trigger.

You can get more water out faster either of two ways:

  • Make the hole bigger. (Increase the voltage.)
  • Pull the trigger harder. (Increase the amperage.)

When it comes to USB connectors, the “size of the hole” is fixed at 5 volts. In a way, that means we can line up or plug in any two holes of the same size, and they’ll fit. (Perhaps you’re using your squirt gun to fill a bottle. If the holes aren’t the same size, things could get messy.)

So the only thing we can control is amperage.

What You Need for Fast Charging

Depending on the device you have, the fast charging standard you’re able to use will vary. Check what your phone supports, then look at your wall adapter to see if it supports the same standard (they’re usually labeled). Then make sure your cable is compatible (you’re best off using one the one that come with your phone or adapter). If you need to buy a new wall adapter, cable, or wireless charging pad, take note of what standard it supports.

And for more charging advice, head over to our story on Charging Your Phone Overnight: Battery Myths Debunked.

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USB chargers

It’s up to the power adapter’s manufacturer to determine the capacity of their device3. Providing more power means using more expensive components, so many USB power adapters err on the side of “not much”.

Here’s how you can tell what you have.

Every charger has its output specifications printed on it somewhere, often in incredibly tiny print. For example: Output 5.1V (5.1 volts4) and 750mA. An adapter with that rating can provide 1.5 times the power of a standard USB data connection from your laptop. Thus, it would charge your device faster (though not necessarily 1.5 times faster, as things are rarely that simple).

Another might offer 2.0A (two Amps, or 2000mA). This charger is capable of providing four times the amount of power as a standard USB data connection. It’ll almost certainly charge your device faster.

How can I check if I have a fast charging cable?

There are a few ways of doing this, including downloading an app. One simple test is – are you still using the cable that came with your phone? If so, and your phone didn’t come equipped with a fast PD GaN charger (or you’re using a cable from an older phone, shock horror), then you might want to change things up.

If you aren’t sure and want to cover all bases, you can buy new, durable and fast charging ready lightning cables and USB-C cables from RAVPower! If you want to know more about our fast charging range, click here.

Check out RAVPower’s range of cables!
Check out RAVPower’s range of cables!

Want to learn more about PD charging? Here’s five reasons you should get a PD charger!