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When buying a used cell phone, it's essential to check its battery condition . A degraded battery can lead to reduced battery life and poor performance. In this article, we'll explain how to assess the battery condition of a used phone to avoid any unpleasant surprises.


Why is it important to check the battery condition?

Over time, batteries lose their original capacity, which can cause:

βœ… Reduced autonomy.
βœ… A phone that suddenly turns off.
βœ… Slower or irregular charging.

Before buying a used phone, it is therefore crucial to examine the condition of its battery.


1. Identify whether the battery is removable or integrated

πŸ”Ή Removable batteries : Easy to replace, available on some older models.
πŸ”Ή Built-in batteries : Present on the majority of modern smartphones, require technical intervention to be replaced.


2. Check the physical wear of the battery

Signs of a bad battery:

❌ Swollen battery.
❌ Deformation of the back of the phone.
❌ Excessive overheating during use.

➑️ Solution : If the battery is in poor condition, it is best to replace it before use.


3. Check battery status via phone settings

On iPhone :

1️⃣ Go to Settings β†’ Battery β†’ Battery Health .
2️⃣ Check the maximum capacity (below 80%, the battery is worn out).

On Android :

1️⃣ Go to Settings β†’ Battery β†’ Battery usage .
2️⃣ Check for any alerts indicating a degraded battery.


4. Use apps to test the battery

Recommended applications:

βœ”οΈ AccuBattery (Android)
βœ”οΈ CoconutBattery (Mac/iPhone)
βœ”οΈ Battery Life (iPhone)


5. Test the phone's real battery life

Quick test : Charge the phone to 100% and note how long it lasts under normal use.

Low battery indicators :

❌ Battery drains very quickly.
❌ Phone turns off before 0%.


6. Check the number of battery charge cycles

πŸ“Œ One charge cycle = one full charge from 0% to 100%.

πŸ”Ή On iPhone : Use CoconutBattery or Battery Life .
πŸ”Ή On Android : Use AccuBattery to estimate cycles.

➑️ Beyond 500 cycles, the battery begins to lose performance.


What to do if the battery is in bad condition?

βœ”οΈ Replace the battery (if possible).
βœ”οΈ Use a power bank to extend battery life.
βœ”οΈ Call a professional repairer .


Tips for extending the life of a used battery

βœ… Avoid full charges to 100% all the time.
βœ… Use a suitable and certified charger.
βœ… Do not leave the phone plugged in overnight.
βœ… Avoid excessive heat, which accelerates battery degradation.


Checking the battery condition before buying a used cell phone is essential to avoid unpleasant surprises. By following these steps, you can be sure of getting a phone with decent battery life and optimal performance.