Apple Explains Why iPhones with Older Batteries Might Seem to Run Slower

Here’s the complete statement provided to TechCrunch:

“Our goal is to deliver the best experience for customers, which includes overall performance and prolonging the life of their devices. Lithium-ion batteries become less capable of supplying peak current demands when in cold conditions, have a low battery charge or as they age over time, which can result in the device unexpectedly shutting down to protect its electronic components.

Last year we released a feature for iPhone 6, iPhone 6s and iPhone SE to smooth out the instantaneous peaks only when needed to prevent the device from unexpectedly shutting down during these conditions. We’ve now extended that feature to iPhone 7 with iOS 11.2, and plan to add support for other products in the future.”

So the very short answer is that Apple “smooths out” the maximum power draw of iPhones with older batteries to prevent a shutdown and spreads that out over a few cycles.

All lithium-ion batteries become less efficient with age, and Apple’s power management system is attempting to balance performance without users seeing random shutdowns.

If your handset is out of warranty, you can have your iPhone battery replaced through Apple for a $79 charge. The battery is backed by a one-year warranty.

Many other third-party shops charge less.