iPhone Battery Replacement | Declining Health, Unexpected Shutdowns and Overheating

Why do iPhone batteries age?

Apple explains that chemical ageing reduces a lithium-ion battery's capacity, shortening battery life and reducing peak performance. This is normal for all lithium-ion batteries, rather than a mechanical fault. Spending long periods fully charged, or frequently charging or operating in high temperatures, can accelerate ageing.

When should I replace an iPhone battery?

• Maximum capacity below 80%: This means battery capacity has declined significantly and runtime will be shorter.
• Unexpected shutdowns: Charge remains on the indicator, but the phone shuts down during use or in cold weather.
• Performance management message: Peak Performance Capability reports a previous unexpected shutdown and that performance management has been applied.
• Rapid drain and heat: Battery charge falls much faster than before under the same usage.
• Battery swelling: If the screen or back is lifting, stop using the device immediately (see safety advice below).

Rapid battery drain is not always a battery fault; background apps, low storage or system issues can contribute. See Software Troubleshooting; charging failure may involve Charging port problems. We inspect to identify the cause rather than immediately recommending a new battery.

Will a new battery make my iPhone faster?

It depends. Apple states that after an unexpected shutdown caused by insufficient peak battery power, performance management helps prevent recurrence. It may slow app launches, scrolling and some games, dim the display or reduce speaker volume. A healthy replacement generally removes the need to limit performance. If the phone has never had a battery-related shutdown, performance management is not automatically enabled; replacement mainly improves runtime.

Extend battery life: Optimised Battery Charging and charge limits

Apple states that Optimised Battery Charging reduces the time an iPhone stays fully charged by delaying charging beyond 80% in certain situations. On iPhone 15 and later, Settings → Battery → Charging lets you set a charge limit from 80% to 100% in 5% increments. Charging stops near your selected limit and resumes after the level falls by more than 5%. Apple also notes that even with a lower limit, the iPhone occasionally charges to 100% to maintain accurate battery readings.

Genuine versus non-genuine batteries: what is the difference?

Apple states that genuine batteries are designed to work correctly with iOS, including accurate reporting of charge level and battery health. Non-genuine batteries may be poorly designed or manufactured, used, damaged or unsuitable for the model, resulting in insufficient capacity, poor fit or performance issues. Problems may appear after installation, a system update or during charging.

*Refer to Apple's official guidance for the differences above. We will explain the battery options and prices after inspection.

We explain the battery type and possible effects before repair so you can choose according to your budget and needs. For parts quality, see Parts quality explained.

How can I tell whether an iPhone battery has been replaced?

Apple states that iPhone XR, iPhone XS and later support Parts and Service History under Settings → General → About. If a repair uses genuine Apple parts and procedures, “Genuine” appears next to the battery. “Unknown” appears if the battery is not genuine, is not functioning properly, has not been verified and linked after repair, or has been modified. You can use this when buying a used iPhone to check whether the battery has been replaced.

How does battery replacement differ between models?

Battery attachment methods differ between iPhone generations. Apple's repair manuals show that iPhone 16 and iPhone 16e use electrically released adhesive, requiring appropriate tools and procedures, and recommend running Repair Assistant after replacement. Apple also states that the foldable iPhone Duo has two batteries. The technician confirms the model and parts availability first; WhatsApp ahead for the latest models. For other model differences, see iPhone Repair.

Official versus independent iPhone battery replacement: which suits you?

Apple's Hong Kong website states that the limited warranty excludes normal battery wear, while AppleCare plans offer free replacement below 80% capacity. Apple's repairs and replacement parts are covered for 90 days or the remaining warranty, whichever is longer. For an out-of-warranty device without AppleCare+, the website estimates HK$999 for an iPhone 18 Pro battery repair (October 2026; check Apple's latest prices).

*Official terms are subject to Apple's latest information. Our terms are stated in the in-person quotation and written warranty. We are not an Apple Authorised Service Provider.

What should I prepare before battery replacement?

• Back up first: Battery replacement normally does not involve the logic board, but back up first as a precaution.
• Make sure you know your passcode: Unlocking is required for testing at collection.
• Take a battery-health screenshot: Compare before and after battery replacement.
• Describe the symptoms clearly: Whether it drains quickly, shuts down suddenly or heats up, and any previous liquid exposure or drops.
• Confirm the battery type:, along with the effects on parts history and the warranty period.

For Android battery replacement, see Samsung Repair and Pixel repairs; for MacBook battery replacement, see MacBook Repair. For more practical advice, see Phone repair guide and Phone repair FAQs.