March 29, 2023 at 2:22 p.m. PST
- The iOS Battery Health statistic measures your iPhone battery’s chemical age.
- The chemical age of your battery depends on age, number of charge cycles, exposure to temperature extremes, humidity, shocks, and other factors.
- Chemical aging of batteries increases electrical impedance, which provides less power for your iPhone.
- Apple abstracts Battery Health into two measurements – Maximum Capacity and Peak Performance Capability, with warning messages for extreme cases.
What is iPhone Battery Health?
Battery Health is a statistic representing your iPhone battery’s chemical age. Your battery’s chemical age refers to its condition over time, charging cycles, and stressors, such as temperature extremes or shocks.
Apple is notoriously tight-lipped on iOS details. Unfortunately, Apple didn’t invent the capability to monitor battery health. My LG Gram laptop had this feature years ago, offering a superior representation of battery health statistics.
Although the Cupertino iPhone maker offers more transparency on battery lifespan, it’s still somewhat opaque and confusing to most end users. Let’s clarify Battery Health.
Apple’s concept of Battery Health refers to how much charge the battery can hold (Maximum Capacity) and whether it can deliver peak power when your iPhone demands it (Peak Performance Capability). Maximum capacity is about how much charge the battery can hold, while Peak Performance Capability refers to its ability to surge power on demand.
Maximum Capacity is represented as a percentage from 0% to 100%. When you get a new iPhone, it should be at 100%. When this number is below 80%, you no longer get the expected runtime of a fully charged iPhone, and you should consider replacing the battery. Typically, Apple will only service an iPhone battery if its below 80% Maximum Capacity.
Apple represents Peak Performance as a series of messages. The following table displays Apple’s Peak Performance messages along with our explanation:
| Peak Performance Message | Explanation |
|---|---|
| “Your Battery is currently experiencing normal peak performance” | Your battery is in great shape and can handle peak power demands. |
| “The iPhone has experienced an unexpected shutdown because the battery was unable to deliver the necessary peak power. Performance management has been applied to help prevent this from happening.” | Apple is throttling performance on your iPhone to prevent it from shutting down. You can disable this behavior, but it’s better for your iPhone to slow down than shut down. I recommend leaving iOS performance management in place. |
| “This iPhone is unable to determine battery health” | Your battery is in such poor condition that iOS can’t even ascertain battery health. Either replace the battery or buy a new iPhone. |
| “This iPhone has experienced an unexpected shutdown because the battery was unable to deliver the necessary peak power. You have manually disabled performance management protections.” | Your iPhone keeps shutting down because you turned off iOS performance management. Unless you enjoy unexpected shutdowns, turn on performance management to slow down your iPhone so that it won’t shut down. |
In addition to Peak Performance messages, Apple displays Important Battery Messages. These are raised for the most severe battery issues. You should take them seriously!
| Important Battery Message | Explanation |
|---|---|
| “Your battery’s health is significantly degraded. An Apple Authorized Service Provider can replace the battery to restore full performance and capacity.” | Your battery is shot, and you should replace it or buy a new iPhone. |
| “Unable to verify this iPhone has a genuine Apple battery. Health information not available for this battery.” | You should always have your iPhone battery replaced at an Apple Store or certified Apple technician. If iOS displayed this message, the replacement battery was so poor it doesn’t offer the diagnostic features to determine battery health. You should replace the battery immediately with an official Apple part, as it may leak, explode, or, at best, offer substandard performance. |
How iPhone Battery Health is Measured
The batteries Apple installs in the newest iPhone models provide diagnostic information to iOS. The data are analyzed and interpreted to produce Maximum Capacity, Peak Performance, and Important Battery Messages.
Most likely, iPhone batteries report statistics like impedance and temperature to iOS. With these data points, Apple can estimate your battery’s performance.
Observations outside of the battery are important too. If your iPhone shuts down unexpectedly because it can’t draw sufficient current from the battery, Apple flags this anomaly and uses it for purposes of Battery Health. In this case, iOS will initiate performance management, so your iPhone slows down instead of shutting down.
It’s important to understand that the official iPhone battery provides diagnostic information for iOS. For this reason, you can’t just get any battery and plop it into your iPhone. Replacing your iPhone’s battery at a legitimate service center is inexpensive. If you do it right, you’ll have 100% Maximum Capacity and normal Peak Performance Capability.
How Battery Health Relates to iPhone Performance
As your iPhone battery ages, your iPhone will slow down. For years, cynics contended that Apple was slowing down iPhones so you’d be forced to buy new ones.
Apple slows down devices to some extent with iOS updates, but I’ve seen it more with the iPad than the iPhone. My 2nd gen iPad was slowed down to uselessness by iOS 8. My old iPhone 6 still runs iOS 12 quite fluidly. It also has 97% Maximum Capacity because I had the battery replaced.
These days, I buy a new iPhone every year, so I’m not as aware of Apple’s planned obsolescence, but I’m sure it’s still in effect. My 8-year-old Apple TV 4 is still performing well, although the UI is more sluggish than when I bought it in 2015.
The truth eventually emerged. Due to a lawsuit, Apple admitted that they slow device performance as the battery ages to prevent unexpected shutdowns. iOS 11.3 added a performance management feature that users could see and deactivate. Although Apple did the right thing, its lack of transparency upset users to the point of lawsuits.
If Apple were more open and honest, much consumer animosity would disappear. They certainly wouldn’t have had so much suspicion and legal action against such a rational decision. When you hide things, you’re going to appear guilty. Apple most likely hid performance management for years to keep things simple for the end user. Thie caused some iPhone customers to believe it was conspiratorial.
How to Reset Battery Health on Your iPhone
Researching this issue, I’ve found some people claim that they’ve improved Maximum Capacity. This is likely due to a statistical anomaly. Colder conditions may temporarily reduce Maximum Capacity, which improves in warmer conditions. It’s likely the result of sustained exposure to cold temperatures, as Maximum Capacity doesn’t fluctuate wildly.
I’ve never seen Maximum Capacity go up on an iPhone. If you want this number back up to 100%, battery replacement is the only option.
Some may have replaced their battery themselves, and they’re wondering how to reset all Battery Health statistics. The DIY kits offer batteries that have 95% Maximum Capacity or higher. This means if you installed the battery yourself and it shows a Maximum Capacity that’s less than 100%, it’s due to battery quality.
It may be worth it. Apple’s cheap battery replacements are history. It now costs up to $99 to replace your iPhone’s battery. You’ll also have to do without a phone or transfer your SIM/eSIM to an older backup phone. Some DIY kits are $39, and you can do it yourself, so you’re not without a device for long. It’s a good option if you own an older iPhone and you’re willing to take the risk.
Installing a genuine Apple battery will reset your iPhone’s Battery Health. It will display 100% Maximum Capacity and reset Peak Performance and Important Battery Messages.
At Appledystopia, we always recommend the best and safest option. If you want to reset Battery Health on your iPhone, it’s best to have Apple replace your iPhone’s battery. Visit Apple’s support site to get started.
If you can’t be without an iPhone or the Apple Store is too expensive, iFixit offers a decent DIY solution for $39 to $44. After replacing your battery, you might see a Maximum Capacity of 95%. But their kit costs as much as 60% less than Apple’s service, and you won’t have to live without an iPhone or use an old spare.
Tips for Reducing Chemical Aging of Your iPhone Battery
If you came to this article trying to make amends with your iPhone battery in the hopes of resetting Battery Health, now you know the truth. Replacing the battery is the only way to reset Battery Health on your iPhone. There are no Settings tweaks that will magically restore Battery Health. But you can sustain Battery Health longer with a few tips:
- Turn off your iPhone when charging. Plug in the charging cable first, or else your iPhone will start up again. This reduces heat when charging, slowing your iPhone battery’s chemical aging.
- Run your iPhone on Low Power Mode. You can always turn it off if you need more power for a game or app. For the most part, you won’t notice the difference unless you have a new iPhone 14 Pro Max with an Always-On display.
- Calibrate your iPhone’s battery. Even though iOS can supposedly recalibrate your iPhone battery, it’s only accurate if you do it manually. My iPhone 14 Pro Max would last 30 minutes at 1% battery life, with everything cranked up and a movie playing. After manual calibration, accuracy improved dramatically.
- Use Dark Mode, especially on a newer iPhone with an OLED display. Since OLEDs illuminate each pixel individually, Dark Mode saves energy.
- Download music and videos that you watch frequently. Network communications, particularly cellular, use a lot of power. If you listen to an album repeatedly, downloading it will save battery power. Download movies and TV shows over Wi-Fi to avoid using power-hungry and costly cellular data.
- Always use secure Wi-Fi when available. If you’re only option is a public Wi-Fi network, VPN will provide sufficient security. Wi-Fi uses much less power than cellular data communications.
- Turn on Optimized Battery Charging. This feature preserves your iPhone battery’s lifespan by limiting battery stress. Optimized Battery Charging analyzes your usage patterns and postpones full charging until immediately before you use it. This is a great way to prolong your iPhone battery’s lifespan, especially if you plug it in before bedtime. Your iPhone will charge to 80%, pause, and then charge to 100% before you wake up.
One can take other, more drastic steps to preserve an iPhone’s battery lifespan. Resetting Battery Health, however, can only be accomplished by replacing the battery. If you decide to take this path, it’s best to get it done at an Apple Store or certified repair shop.
For those with nothing to lose, DIY kits make it easier to replace an iPhone battery. Just be aware that the batteries are of lesser quality than what you’d get from Apple. You may replace the battery only to find it has a Maximum Capacity of 95%. If this is the case, you can’t reset Battery Health on your iPhone and get it up to 100%.
Diminished Battery Health can be the result of an inferior replacement battery. You can dig the battery out of your iPhone and return it. Most iPhone battery DIY kits offer a return policy because few will deconstruct their iPhones over 5% battery capacity. You get what you pay for.