Here’s how to check your iPhone’s battery health, reliably and for free

Atherton Research

Apple Made Billions Hiding That It Slowed iPhone Performance with an aging battery, pushing people to buy a new phone rather than a new battery.

Worse still, the tech giant only admitted to the existence of its secret power management ‘feature’ in iOS to prevent phones from ‘sudden shutdowns’ only after being taken in the act by performance benchmark tool Geekbench last December.

More than a month later, Apple still hasn’t released the iOS 11.3 software update that will allow iPhone owners to turn off the “battery saver” feature that plagues the iPhone. 6, 6 Plus, SE, 6S, 6S Plus, 7 and 7 Plus.

The tech juggernaut, which just had the best iPhone year ever in 2017, also promised that the update will show the health of the phone’s battery and a recommendation on whether the battery should be replaced. However, in the meantime, Apple still bans battery health apps from App Store for security reasons . Go figure!

There is hope, however. Mac developer Chris Sinai released a free app, coconut batterywhich measures the current state of the internal battery of your Mac as well as all iOS devices (iPhone, iPad and iPod touch) connected to it.

It shows your battery’s current charge level, its full charge capacity and most importantly its design capacity, which is the original capacity of your battery when it left the factory.

Apple officially calls a battery “bad” when its health drops below 80% within the first 1000 charge cycles. In our tests, the batteries of the iPhone 5 (28.8%) and 6S (76.6%) need replacing while the 2-year-old 6S Plus is at the limit (80.8%) and the brand new iPhone X is already down a notch (99.5%).

Sinai’s battery app also offers other interesting information like the age of your battery, the number of cycles (how often has your battery been charged from 0% to 100%) that needs to be maintained low to increase the life of your battery, as well as the temperature inside your battery.

Below is an edited transcript of my email conversation with Sinai about why iPhones suddenly shut down and his take on the performance throttling issue.

Jean Baptiste Su: How would you explain that a phone turns off even if it indicates that there is 20% or more battery charge left?

Chris Sinai: This is quite a complex technical (and chemical) subject but in short: A battery is not like a bucket full of energy that you can dip into until it is empty. Due to the law of physics, the maximum amount of amperage you can draw from a battery depends on temperature (when a battery gets cold, you can’t draw as much power from it as when it was hot, you also see it on car batteries in the winter) and the charge level (you can’t draw as much power from the battery when it has a low charge). Normally, a device manufacturer needs to accurately calculate the battery capacity and power consumption of the device to avoid sudden shutdown. I guess Apple tried really hard to get that much power into their devices and maximize battery life and couldn’t find the right setting.

JBS: Is there a way to tell if your device is throttled?

CS: Sure, personally I can see some animations stutter, but there are also a few tools that can read the current CPU speed or benchmark your device.

JBS: What’s your take on this battery performance throttling issue?

CS: From a technical point of view, this throttling makes sense if the battery cannot provide the necessary power. (a choke is better than a stop). From all other points of view, Apple’s lack of communication is really the problem here. Only Apple can tell if older phones are also throttled, maybe they found the right power consumption/battery size setting in those devices or they just don’t cover them because those devices are “obsolete”. Apple really tries hard to steer users away from technical matters, but in this case, communication would have been the key to trust.