Here's exactly how your iPhone gets slower when you have an old battery

Here's exactly how your iPhone gets slower when you have an old battery

iPhone 6

Ben Gilbert / Tech Insider

  • Apple apologized on Thursday because some customers are upset that it slows down iPhones with slower batteries.
  • Older iPhones can take longer to launch apps, may display choppy scrolling, and can have dimmer screens and quieter speakers.
  • According to Apple, it's a "power management" feature that helps protect the iPhone from random shutdowns and damage to its components.

If you've got an iPhone that's getting on in age you may have noticed it runs slower after the latest updates.

That's because Apple slows down older iPhones when they have aging batteries. According to Apple, software updates throttle older iPhones because their batteries are "less capable of delivering peak energy loads," according to an apology the company issued on Thursday.

If you're wondering what slower performance means for your iPhone, Apple posted a help document on Thursday that outlines exactly what its "power management" does.

If your phone has a really old battery, Apple says that your phone may take longer to launch apps, and may display apps at lower frame rates - meaning you get a choppy user experience


Here's the full list of reductions in performance your iPhone might see with an old battery:

  • Longer app launch times
  • Lower frame rates while scrolling
  • Backlight dimming (which can be overridden in Control Center)
  • Lower speaker volume by up to -3dB
  • Gradual frame rate reductions in some apps
  • During the most extreme cases, the camera flash will be disabled as visible in the camera UI
  • Apps refreshing in background may require reloading upon launch

Apple also provided a list of features that won't be affected by on older iPhones:

  • Cellular call quality and networking throughput performance
  • Captured photo and video quality
  • GPS performance
  • Location accuracy
  • Sensors like gyroscope, accelerometer, barometer
  • Apple Pay

How to fix it

iPhone 6s lower power mode


Here's Apple's technical explanation for its power management software:

"This power management works by looking at a combination of the device temperature, battery state of charge, and the battery's impedance. Only if these variables require it, iOS will dynamically manage the maximum performance of some system components, such as the CPU and GPU in order to prevent unexpected shutdowns."

"As a result, the device workloads will self-balance, allowing a smoother distribution of system tasks, rather than larger, quick spikes of performance all at once. In some cases, a user may not notice any differences in daily device performance. The level of perceived change depends on how much power management is required for a particular device," it continued.


Basically, in English, this means that an iPhone with an older battery can't provide enough power to operate at full capacity without hurting the iPhone's components. When an iPhone realizes the battery might not provide enough voltage and could hurt its parts, it automatically shuts down. That's a feature, according to Apple.

So Apple programmed a new piece of software that would prevent the iPhone from taking full advantage of its components. Instead of letting the iPhone run at full power, Apple instead has its phones "self-balance" and take a little longer to complete tasks.

The good news is that replacing the battery on your iPhone 6, iPhone 6S, or iPhone 7 should help it get back to full strength. If you're unsure if your battery is old, Apple will release a software update that will let you check on its health. For the next year, Apple is only charging $29 for a battery replacement at one of its stores.

The battery replacement deal will start in late January, according to Apple.

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