The Beginner’s Guide to your Phone Battery

Understand how your phone battery works and how you can make it last longer

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To say that the smartphone is a crucial component of our everyday lives is an understatement. Just over 20 years ago, it would have been inconceivable that our phones could do what it does today. Of course, with the increase in smartphone capabilities comes an increase in demand for electrical power. This has resulted in huge amounts of investment into Research & Development aiming to improve several components of the smartphone battery from size to capacity. In this Guide, we will explore how phone batteries work, some of characteristics you should look for in a battery and how you can make your phone battery’s charge last longer.

How do phone batteries work?

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There are more than 80 kinds of batteries that exist today. This ranges from the science fair’s potato battery to the atomic battery that gets its power from decaying radioactive isotopes. For today, however, we will be looking at a specific kind of battery: Lithium-Ion batteries. This is the battery that is commonly used to power the phone in your hands.

Battery 101. Electricity is essentially the flow of electrons through a conductive path. To do that, three key components are often needed. You need the anode, which is the negative end of the battery. You may normally recognise the anode as the ‘-’ sign on your battery. A chemical reaction within the anode builds up electrons and positive ions. The second component is the cathode, which does not build up any of those. This is often symbolised by the ‘+’ sign on your battery. The electrons will attempt to equalise this difference by moving to the cathode. Now, we reach the third component: the electrolyte. The electrolyte acts as an insulator that prevents electrons from passing through it. It is located between the cathode and the anode, blocking them from each other. This means that the electrons are unable to move directly from the cathode to the anode. As such, they are trapped in their own territory.

When there is a conductor connecting the cathode and the anode together outside the battery (such as an electrical cable or wire), the electrons now have an alternate way to move from the anode to the cathode. As the electrons attempt to move through the conductor, the positive ions move the other direction into the electrolyte towards the cathode. This movement of electrons through the conductor provides power to any electrical device connected to the conductor, creating electrical power. The electrons then complete the circuit by heading back into the cathode and recombining with the positive ions.

Battery Drainage. Of course, we know that a battery’s charge does not last forever. One thing to note is that these movements of electrons and ions are chemical reactions. This means that as the electrons and ions are moving, the chemicals within the cathode and anode are being converted. This reduces their ability to generate power, reducing the voltage and thus the battery slowly gets drained.

Battery Charging. Upon charging, the process is reversed. The positive ions will move back through the electrolyte into the anode. The electrons will take the longer path in the circuit to move back into the anode, where they recombine. After the entire process is complete, the battery is fully charged and ready for use.

Lithium-Ion Batteries. Across the different varieties of batteries, the above concept stays similar. Most batteries contain a cathode, an anode and an electrolyte. A key change between these different batteries are the chemicals used inside the cathode, anode and electrolytes. Different chemicals used means different types of chemical reactions producing different rates of electrons and positive ions. This in turn represents different levels of battery power, voltage and sustenance. Smartphones manufacturers such as Apple and Samsung often use batteries in the Lithium-Ion variety. This is because Lithium is one of the lightest metals and has great electrochemical potential. For its weight, it also has the largest energy density. While attempts at rechargeable Lithium batteries failed due to instability issues, Lithium-Ion is much safer and more stable. It also causes less environmental damage when disposed as compared to traditional battery compositions.

Phone battery characteristics

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From the energy density to the watt hours, there are several features you can use to determine the quality of your phone battery. This Guide will focus on a few key common features: Battery Capacity, Battery Life and Battery Size.

Battery Capacity. The battery capacity represents the amount of power your battery can hold. From a technical perspective, this is amount of lithium ions that are within the anode and cathode. A common way to measure battery capacity is through mAH. It stands for a milliampere hour, and it measure the rate of electron flow through the electrical conductor. In other words, it measures the amount of power your phone battery or power bank can hold. A cheap power bank will range in the vicinity of 3,000 mAH while a powerful one can range all the way to 50,000 mAH. To put that into perspective, your iPhone X’s battery capacity is 2,716 mAH, so that’s equivalent to charging your iPhone more than 18 times!

Battery Life. The battery life is the time taken before your device runs itself out of power. Unlike the battery capacity, the battery life is affected by several external factors such as battery discharge rate and temperature conditions.

Battery Lifespan.With each charge and discharge, the amount of lithium ions within the cathode and anode lessen. The battery life is the measure of how many charges and discharges a battery can make before it completely loses its viability as a power storage device. This is different from the battery life which only measures the time for one singular discharge. Apple estimates its iPhone's lifespan to be 300 to 500 charges, which should last you for about one and a half to 2 years. This means that your iPhone’s battery life will start decreasing significantly to about 80% levels on full charge after 500 charges, and will continue to dwindle down to 0% as more charges are used on the battery.

Now that we understand the key concepts behind how a battery work and how to measure battery effectiveness, let’s look at some factors that affect your battery’s charge, and how you can make your phone battery last longer.

How do I make my phone battery last longer?

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There are several ways to protect your battery’s life and lifespan with minimal effort. Let’s take a look.

Keep your case off when charging your phone. Most of us know that extreme temperatures affect our phone’s battery life. While this may not be applicable most of the time, we tend to forget that our phone generates heat too. In normal circumstances, the heat generated is not severe enough to cause a significant decrease in your phone’s battery life. However, akin to wearing a winter coat in summer, the heat emitted by the phone may be conducted back to your phone through your phone case. This would definitely affect your phone’s battery life, much less the other components in your phone which may be even more temperature-sensitive.

Use a black or dark background for your phone. Most newer flagship smartphone models manufactured from Apple and Samsung use what is known as OLED screens. What has that got to do with your phone’s battery charge? Quite a bit, in fact. Traditional phones use LED screens, which work by using a back-light. This means that the screen actually uses a significant amount of power as long as it is on. OLED screens, on the other hand, consist of individual pixels that only lights up when it is needed. This means that, by using a black background, a huge part of your phone screen’s pixels stay unlit as compared to bright neon colourful background screens. This of course, means that your phone uses less power when it is displaying the background image.

Don’t use up your phone’s battery completely. Traditional wisdom tells us that, to maximise your phone battery’s lifespan, we should use each charge to the fullest. This means people have been draining their phone battery fully and then charging it back up. While this may be best practice for the older battery models, Lithium-Ion batteries are not built for this. As such, you should not drain your battery fully and then charge it back up often on your phone as this may destroy the battery’s lifespan. Charge it often.

Use the Low Power Mode. While most people know about the Low Power mode, people only use it when it gets automatically activated on low charge. Low Power mode takes on a series of actions to increase the efficiency of your remaining charge such as reducing your phone’s brightness and stopping background tasks. If your phone often dies on a full day out, you could perhaps consider switching it on once it hits 80% capacity, instead of waiting until it switches on automatically at 20%.

Use Wi-Fi rather than 4G. 4G actually uses significantly more power than Wi-Fi. In fact, some network providers (such as Verizon in the US) actually set up your smartphones to utilise both 3G and 4G networks at the same time, consuming twice the amount of power to maintain a network connection. As such, you should connect to Wi-Fi whenever possible, even if you have an unlimited 4G plan. This will help to save your phone’s battery charge and thus lifespan in the long run.

A smartphone is essential in our daily lives, but its’ usefulness last as long as there is power to juice it up. With this understanding of how your phone’s battery works and how you can make your phone’s battery charge last longer, you can hopefully prevent your phone from dying before your day is done.


About The Beginner’s Guide:
The Beginner’s Guide series provides you with a quick understanding of everyday items that you come in contact with. This includes articles on how something works, where something originated from, or how to make something better. All to provide you with tidbits of information that you can use to show off at your next dinner party.

Author’s Note:
My phone often runs out of battery before the day is done, and it would often result in me bringing along bulky power banks. This was the inspiration for the Guide. I hope this Guide has helped you understand what’s going on within the battery when it discharges, and how to make your charge last longer!