Don’t Buy a Used Phone Without Checking the Battery: Here’s How

Lithium-ion batteries are great for everyday use; however, they have one major issue. Just like with anything, they degrade with time, meaning a phone battery will not be efficient enough after substantial usage. With each cycle of charging and discharging, these batteries wear out, chip by chip. If it’s your personal phone, there is a chance you might ignore the degrading performance, but battery performance plays a very important role once you decide to sell it or buy a used phone. 

 Luckily, many phones have built-in battery health tracking apps that tell you the performance index. However, there are also some third-party apps that go into detail if you are interested in finding out exact details.  

In this article, you will learn how to use the built-in as well as the third-party health checkers. Since smartphones are at an all-time expensive streak, buying a secondhand phone might be your only option, and you cannot let a degrading battery ruin it all. 

Why Do Phone Batteries Degrade? 

It is obvious that any piece of electrical and electronic equipment runs its course eventually. However, what specific reasons are there that cause batteries to fizzle out, and is there any way to mitigate these? Let’s find out: 

Chemical Cycles 

Charging cycles are key to understanding battery degradation. Li-ion batteries are built to only run between 500 to 1000 charging cycles, where one charging cycle means draining a full battery.  

Temperature 

Extreme temperatures (both hot and cold) can hasten battery degradation. While low temperatures can stop chemical processes, reducing performance, high temperatures can cause the electrolyte of the battery to degrade chemically.

Age 

Age is the one constant that causes batteries to deteriorate regardless of how you use it. Sine the chemical changes occurring inside the battery can only be partially reversed, so does the capacity and performance of the battery in general, leading to a significant drop in performance over time. 

Checklist for a Used Phone 

Whether as a buyer or seller, a used phone should have the following parameters checked on both ends for peace of mind: 

• Original purchase receipt 
• Physical damage to the phone 
• Phone battery performance 
• Original charger and cable 
• Repair history 
• Miscellaneous (checking charging ports, jacks, connectivity, etc.) 

For a used phone, a typical Lithium-ion battery will last a good two years before degradation. It is always good to check the battery health of the phone even if it’s refurbished or used. If you cannot find any settings to check battery health, try using the phone for five to ten minutes and observe the drop in the percentage.  

If the battery performance is not at par, it is a good gesture as a seller to be open about it. As a buyer, you must negotiate for a better price if you feel that the phone battery is acting up. However, to make an informed choice, you would still require the secret test to know if a used phone’s battery is any good. Read on to find out.  

How to Check Battery Health on a Used Phone 

Now, let’s get into the nitty-gritty of evaluating a used phone’s battery. Different operating systems offer various tools and methods: 

iPhones 

The best thing about battery health monitoring on iPhones is that they have a built-in setting for it. Here is how you can check on a used iPhone: 

• Navigate to Settings > Battery > Battery Health 
• Go to Battery Health & Charging (iOS 18 and above) > Maximum Capacity percentage for current battery capacity. For reference, a healthy battery should be at least 80% of its original capacity. Below 80% is a guaranteed replacement case. 
• Also check the Peak Performance Capability section, containing Optimized Battery Charging and Clean Energy Charging. This section tells the user about the normal peak of performance the battery currently supports based on the daily charging routine to optimize energy consumption. 

Android Phones 

Since Android is not a single tier operating system, there is no one way to find battery health. It varies from phone manufacturer to phone manufacturer. Here are some of the most common ways: 

• Using Built-In Tools 
• Third-Party Apps 
• Using Codes (Samsung phones exclusively) 

Using Built-In Tools  

Android still does not have an official way to analyze battery health. However, there are some manufacturers (Xiaomi, Redmi, other Chinese brands) who offer settings that can give some information about battery.  

• To check if your Android has those settings, go to Settings > Battery. 
• Under the Battery section, scroll down until you see Battery Health. 
• Check the Battery Health Percentage and Battery Temperature listed in this section. 

You cannot interact with these settings, but you can see what the condition of the used/refurbished Android phone is based on these settings. It goes without saying that this is not all the picture, and you must dig deep to find the battery condition. 

Third-Party Apps  

Fortunately, there are quite a few battery check monitoring apps out there, some of which include: 

AccuBattery

This app measures actual battery usage and provides insights into battery capacity (mAh), charging speeds, and helps find the fastest charger and USB cable for your device.  

Battery Health Checker

This app allows you to perform a complete diagnosis of your device’s battery with a one-click tool, providing information such as temperature, voltage, and battery technology.  

BATT – Battery Health Checker

This app provides real-time insights and alerts to help you manage your battery, with features to help maximize your phone’s battery life.  

aBattery 

This app offers detailed information about battery health, maximum capacity, production date, and more, with a Material Design 3 UI.  

Battery Guru

This app offers detailed battery statistics and monitors charging activity, allowing for thorough analysis of battery health, discharge rates, and usage patterns.  

Battery Life & Health App

This app is a “One-click app” to check the status of your battery, calibrate battery status easily, and check temperature, voltage, and technology indicator.  

Using Codes 

Samsung users can dial *#*#4636#*#* to access information like battery health and usage statistics. Please note that in other phones, this code can lead to a screen showing phone information like the mobile network, signal strength, Wi-Fi information and DL Bandwidth etc.  In such settings, you can do a ping test for checking phone features but may not see any battery-related information. 

Secret Tip to Check a Used Phone Battery 

Beyond software diagnostics, a hands-on approach can reveal much about a battery’s condition. Popular among older models, this method checks battery health against any visible swelling on the back. Place the phone on a flat surface and try to budge or spin it. If the phone wabbles, there is a reason it does because of outdated battery.  

Since many newer phones do not allow battery detachment, you can closely monitor the back cover. If it feels uneven and fattened in the middle or where the batter generally is, there might be a performance issue with the battery. 

There is another secret hack to check battery health on bulged battery phones: the charging test.  

You can always plug it in the socket and check how fast it heats up. Sometimes these phones give off uneven charging percentages as well, so keep an eye out. 

In Conclusion 

Maintaining the performance and lifetime of your phone depends on you keeping an eye on your Android battery condition. Whether you use a device history report, third-party apps, or built-in capabilities, keeping informed helps you make better choices.  

You may increase the lifetime of your phone and cut replacements by changing your charging habits and often monitoring battery life. While buying a secondhand smartphone can be a wise financial decision, only if you know how to look for battery life will it be.  

Fortunately, phones include built-in tools and third-party apps that illustrate how well the batteries can provide power. The vendor also must run and screenshot these tests on their own and be honest about the findings regardless of their outcome.