Phone chargers explained. Lightning Charger

How to Choose a Portable USB Charger and Battery Pack

Jason Hidalgo is an award-winning technology and business journalist whose writing has also appeared in Engadget, USA Today, and the Reno Gazette-Journal.

Jessica Kormos is a writer and editor with 15 years’ experience writing articles, copy, and UX content for, Rosenfeld Media, and many others.

What to Know

  • Choose a battery pack that’s large enough to charge your phone fully in one go.
  • If you’ll carry it around all day, make sure it’s a comfortable size.
  • Make sure the battery pack will charge your devices quickly.

This article explains everything you should think about when buying a USB charger so that you can get exactly what you need. For actual examples, check out our roundup of the best USB battery chargers, portable laptop battery chargers, and portable solar chargers.


Just like how portable gadgets come in all sorts of shapes and sizes, portable battery packs come in an assortment of capacities as well.

A small charging stick might come with 2,000 mAh (milliamp hours) of juice, but there are also heavyweight mobile chargers that can pack over 20,000 mAh of battery power.

Here are some questions you should answer when it comes to picking the right charger size for you:

  • Which devices do you plan to use with the battery pack?
  • How many different devices do you plan to use with it simultaneously?
  • For how long will you be away from a wall charger? In other words, how many times do you think you’ll need to use the same portable battery before you’ll be able to recharge it?

At the very least, you want to get a portable charger that can charge your target device fully in one go. To do that, you’ll need to know the energy capacity of the device you’ll be charging. Once you know your device’s capacity, just check out whatever portable battery you’re looking into and see what its own mAh capacity is. A small 3,000 mAh charger, for example, would be more than enough to fully charge most smartphones.

If you’re looking to charge larger devices like tablets or laptops, you’ll need a charger with way more juice. Even if you don’t own a large device, you may own multiple smaller gadgets like a personal phone, work phone, and an MP3 player. In that case, getting a USB battery pack with a larger capacity and more than two USB ports might be helpful, too, in case you need to charge several devices at the same time.

Size and Weight

Another factor that might be important to you when considering what to buy is the mobile charger’s physical size and weight. If you’ll be carrying this thing around with you all day, you want it to be a comfortable size, but that just isn’t how some power banks are made.

Generally, if the charger has a smaller battery (the mAh number is smaller), and it only has one or two USB ports, it will be of a significantly smaller physical size than one that is triple the capacity and has four USB ports.

In fact, some of the really large capacity portable batteries that support USB and regular plugs (like for laptops), are akin to bricks. they’re huge and heavy. This makes it harder to hold in your hand or put in your

However, if you plan to keep the battery charger on the table and store it in your bag, it won’t be a big deal to you. In short, if you commute on foot or are a student who walks to and from classes, a smaller charger would be a better option for backup power, maybe even a phone case charger combo.

Explained: Smartphone Fast-Chargers, And How Fast Charging Works

The importance of smartphones and our dependency seldom needs explanation. It would be hard to even imagine a day without them. We need it and also want it almost throughout the day. And an important component of smartphones that lead to them being used for a long time and remotely is their battery.

With most smartphones having battery backup for almost the whole day, charging them almost always is painstakingly slow. However, a recent phenomenon of fast charging has made things much easier for users. Most smartphones, especially the recent ones with fast charging get a full charge in under an hour.

What is fast charging?

Fast charging’s popularity is due to rising phone usage, with many people needing to recharge their phones many times each day. It’s also a requirement as phone sizes increase year after year, larger batteries are required to keep up with the increased power usage. We’d have to wait hours for our phones to charge if they didn’t have Rapid charging.

Unsplash/Representational image

phone, chargers, explained, lightning

Fast charging, as the name suggests, is a function that allows a user to charge his or her smartphone in less time than one would with a standard device. Fast charging refers to the process of delivering more power to the smartphone in a short amount of time. The number of watts (W) entering the smartphone’s battery is raised during fast charging.

How fast charging works

The fast charging process can be divided into three stages:

Stage 1 – Constant Current: Voltage increases towards its peak, while current stays constant at a high level. This is the phase where a lot of power is quickly delivered to the device.

Stage 2 – Saturation: This is the phase where the voltage has reached its peak and the current drops down.

Stage 3 – Trickle/Topping: The battery is fully charged. In this phase, the power will either slowly trickle in, or will periodically charge a low “topping” amount as the phone consumes battery.

Fast charging works on the same concept as conventional charging, but the amount of electrical power (Ampere) converted and sent over the cable is substantially larger. The voltage of a common adaptor ranges from 2 volts to 4.2 volts, with a low electrical transfer rate. A fast-charging adaptor, on the other hand, can build a significantly higher voltage (5V-12V) and transfer electricity much faster until the battery reaches its maximum voltage capacity.

To swiftly charge the battery, it pumps as much current (Amperes) as it can. Many of us may wonder as to why high voltages do not harm the battery. As the fast charging devices have a higher peak voltage capacity batteries and specially designed ICs the electronic controller which drops down the voltage intakes to prevent battery damage, so it can handle pretty high voltages with ease. Fast charging is most successful when the battery percentage is below 50% because these devices often have an 80 percent peak voltage capacity.

phone, chargers, explained, lightning

Unsplash/Representational image

Difference in fast charging speeds

When charging from a USB port, the average smartphone receives about 2.5W to 6W. Fast chargers increase that amount by almost 10 times, with some reaching 120W. Not all phones support fast charging, and not all chargers are fast chargers. One will need a charger and a phone that supports fast charging for fast charging to operate.

phone, chargers, explained, lightning

There are two stages of fast charging. A greater voltage boosts the charging rate in the first phase. This phase is used by fast charging chargers to increase power flow. When the battery has received the majority of its charge, the charger reduces the voltage to prevent overheating or overcharging, assuring the safety of both smartphone and charger.

There’s also the emergence of wireless fast charging. Without effective thermal control, transmitting huge quantities of power wirelessly can become harmful. Because technology companies are still working out how to regulate the heat, wireless charging is still much slower than conventional charging.


Wireless charging sounds like one of the modern advancements of the 21st century. But the basic principle of wireless charging has been around a lot longer than that. The seemingly modern science of wireless charging is quite similar to Nikola Tesla’s resonant-inductive coupling process – the method he used to light his laboratory in the late 1800s (yes, that long ago).

phone, chargers, explained, lightning

This inductive charging method worked by creating a magnetic field between a transmitter and a receiver, which transmitted electricity directly through the airwaves. Eventually, Tesla created and patented the Tesla coil tower that shot electricity across a space. He had hoped to one day use this invention to create a wireless power grid to use his inductive charging on a broader scale. While this never happened in his lifetime, it’s very close to the way we wirelessly charge our phones today.

Fast forward to today: A wireless charging device or accessory is designed with an electromagnetic coil positioned inside. These electromagnetic coils are basically an induction coil in a charging base, which creates an antenna-like magnetic field that sends energy to your phone. But how does the phone catch this electromagnetic energy? Through a receiver. Inside your phone is an even smaller electromagnetic coil that receives the energy thrown out by the induction coil and transfers that energy back into the phone’s battery.

That’s what is going on beneath the hood when we place a phone or device down on a wireless charger.


All in all, wireless charging offers a mess-free, convenient method to charge your phone, earbuds, smartwatch and more. It provides lots of benefits, which is why there are so many wireless charging compatible phone accessories available to us. However, there is one downside to a wireless charging accessory: It is not as efficient as wired charging or a fast-charging cable.

In fact, distance plays a huge role, too. The further away your device’s receiver is from the wireless charger’s transmitter, the slower it will charge. Essentially, the magnetic field will struggle to transmit power to the device if it’s not directly on top of the wireless charger. Even if it’s knocked off by a few millimeters, it can slow the charging process.

Common sense says that this drawback could be easily solved by simply building a larger transmitter. However, it’s not that simple. Creating a larger transmitter would mean having to build a large wireless charging receiver inside the phone. And the science is just not there yet.

Still, there are advancements in wireless charging being made each year. Eventually, we may see phones with smaller and stronger receivers, allowing them to pick up energy even if it’s a little more than off-kilter from the wireless charger.


So if wireless charging is not as fast as plugging your device directly into the cable, how fast is it? What can you expect from a wireless charging device and are there ways of making it faster?

First, you must understand that the typical maximum charging speed of a device is 10 watts. While you can find 15-watt chargers and stronger, 10 watts is average. Fast chargers are something else entirely. You will commonly find fast charge adapters to offer anywhere from 10 to 65 watts, using the Quick Charge technology and Qi standard.

However, wireless charging has a hard time keeping up with this level of speed. Instead, a wireless charger presents a few challenges – like physical design and materials – that prevent it from charging as efficiently as it should. Otherwise, the transmitting coil inside would do its job properly and without a hitch. Look at it this way – there was once a time when wireless chargers wouldn’t work with a phone case. Now, that’s not an issue. So, as it goes to show, the speed and efficiency of a wireless charger will continue to get better in time, regardless of aligned coils.

Today, you can find a wide range of fast chargers to get your device charged in no time. While it’s not as fast as a direct cable contact, Case-Mate even offers wireless fast chargers that can reach up to 15 watts.

The Most Popular Types of Charging Cables

In the past several years, smartphone manufacturers have opted to move away from the micro-USB and have begun integrating the USB-C into most of their devices. over, there is the potential for even greater adoption for this type of charging cable as Europe may require all phone manufacturers to use USB-C charging cables. Naturally, this has some major implications for future models of the iPhone.

The reason that so many phones have adopted the USB-C port are many. Firstly, as mentioned earlier, it is much faster in terms of charging. Additionally, it is easier to use given that it does not demand a specific orientation.

To get a scope of just how popular the USB-C charger has become for smartphone devices, GSMArena’s phone finder feature shows that there are currently just under 1,400 Android phones on the market using USB-C.

This means that all Samsung Galaxy phones beyond the S7 feature USB-C support. over, new generations of the Samsung Galaxy Tab also use this type of charging cable.

Additionally, Motorola has made the leap to USB-C as well, which means that all of the company’s modern devices have a USB-C port. The same goes for HTC, OnePlus, Huawei and others.

While Google Pixel also has this type of charging cable, the fact is that it never came with a micro-USB, so the USB-C is native to this device.

In a nutshell, if your phone was manufactured after 2016, there is a pretty good chance that it is using a USB-C style charger.

Between the existing demand for this type of charging cable and Europe’s potential move forcing the USB-C onto manufacturers, there is a chance we might see Apple make the move after all.

Which Type of Charging Cable Do You Need?

As far as figuring out which type of charging cable you need for your phone, computer or otherwise, the best way to establish this answer is to simply reference the item’s original packaging or user manual.

However, if you don’t have either of these, you can simply check with the manufacturer or conduct a simple Google search.

As was touched upon earlier, if your device was produced after 2016, there is a great chance that you will need a USB-C charging cable. However, if you are using an older model Android, then it is highly likely that a micro-USB will be in your future. On the other hand, if you are an iPhone user, then buying an Apple Lightning cable is certainly the way to go.

Advice for Buying Charging Cables

The fact of the matter is that even if you have a newer Android phone or you are a dedicated Apple user, there is a significant chance that you will still need a micro-USB cable at some point in time as they are still commonplace on Bluetooth® speakers, battery packs and other types of electronics. And if you don’t, a friend or family member likely will.

While many of the devices that utilize such a charging cable tend to come with one in the box, in time, cables will get run down, broken or just lost. This means that you will probably have to buy one at some point.

When purchasing a new cable, many opt to go for the cheapest possible option. While this may be tempting, it is not advisable as poorly made cables often come with a host of potential issues. These problems range from minor annoyances such as slow charging to outright dangerous complications such as becoming a fire hazard.

In fact, when USB-C was still new to the market, many cables were manufactured incorrectly and damaged devices. While modern cables are far less likely to have such an issue, this served as a warning to many that it is best to just ante up for a good cable.

That said, you don’t have to go directly to the manufacturer to get a cable. However, it is advisable to stick with reputable, recognizable brands like Scosche.

over, when purchasing a new charging cable, be sure to take length into consideration. While short cables can be good for portability and home use, they can also leave you stuck holding your device next to the power outlet as your phone charges. On the other hand, if the cable is too long, it can become tangled and inconvenient to bring places.

If you are looking for that Goldilocks solution, three feet tends to be a good all-in-one type of solution. This is long enough to use your phone while it is connected to a battery pack in your but still short enough to use while at a desk.

Using the Right Types of Charging Cables

As you have seen, there are a variety of different types of charging cables in use today. Not all of them are going to work for every device of every manufacturer, so making sure that you have the right cable for you is important.

However, with the advent of wireless charging, new options are becoming available to consumers as well.

Nonetheless, while charging cables are still a commonplace piece of equipment, getting quality products is vital to maintaining your equipment and a great experience. If you need to pick up a new charging cable, shop Scosche’s collection of cables and adapters to find the right one for your device.

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