This is a sign that you need to replace your iPhone battery.

An aging iPhone battery experiences increased resistance, resulting in insufficient voltage for demanding tasks. Therefore, the device will automatically shut down to protect its components, even though the battery percentage may still be displayed on the screen. (Image: Tom's Guide )

Battery capacity dropping below 80% occurs when the device reaches its charging cycle limit. iPhones 14 and earlier models begin to degrade after 500 cycles, while iPhone 15 and later models can reach 1,000 cycles. When the maximum capacity drops below a safe level, the device tends to slow down, shut down unexpectedly, and require frequent charging throughout the day. (Image: 9to5Mac )

Normally, iOS displays a low battery warning when the battery level drops below 80%, but this notification may appear sooner. Even batteries with high capacity can have high internal resistance, causing the device to shut down unexpectedly when taking photos or playing games. Image: iMore .

Charging for too long is a warning sign of battery problems. An iPhone 17 Pro reaches 50% in just 20 minutes with a 40W charger. If the phone takes an hour to charge, even with a good cable and charging port, the battery needs replacing for stable device operation. (Image: PCMag )

Abnormally rapid battery drain is a sign of chemical aging, meaning the components can no longer hold a charge as long as before, even with proper battery saving measures. Normally, a new battery should last a full day with basic usage. Photo: The Sun.

Swollen lithium-ion batteries pose a serious fire and explosion risk, which can be visible through a bulging screen or back cover. This requires immediate service at a service center. (Image: MacRumor )

Constantly overheating on an iPhone indicates that the old battery is providing unstable power, causing it to overwork and generate heat. Ignoring this warning can damage many internal components. Image: Nytstnd .

Apple automatically limits CPU and GPU performance when the battery is low to prevent sudden power outages. As a result, apps open slowly, scrolling is laggy, speaker volume decreases, and the flashlight may be completely disabled. Image: Phonearena .

When the battery has completely lost its ability to store charge, the iPhone will only work when plugged directly into a power source. This is the clearest sign that the battery needs replacing immediately, before the device is no longer able to back up all its data. Photo: Asurion .

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