Your iPhone uses a lithium-ion battery that degrades over time, but there is little reason to worry about battery health in a new device. Here’s what you need to know about your iPhone’s battery.
Batteries are not mysterious black boxes that power your iPhone, in fact, they are quite simple products compared to the advanced silicon they are powering. The physical nature of batteries mean that they will ultimately wear out and become less useful over time, but device owners don’t need to worry.
Understanding a little bit of the science behind batteries can go a long way in intelligently managing your device’s lifespan. Controversies surrounding iPhone relating to planned obsolescence and expected upgrade cycles can easily be dismissed as hyperbole with a little bit of knowledge.Lithium-ion battery basicsA battery consists of an anode (+) and cathode (-) separated by a generally flammable electrolyte. When a device draws power from the battery, charged lithium ions move from the anode to the cathode through the electrolyte, releasing electrons.
These freed electrons power the device and return to the cathode, creating a complete electrical circuit. The opposite occurs when charging the device — electrons are passed into the anode and move to the cathode.
Without getting too technical, these two chemical reactions are imperfect and introduce heat loss and wear to the battery. The lithium material slowly depletes, oxidization reduces usable surface area, and filaments grow from battery plates. All this leads to cell degradation and eventual battery exhaustion .
There is nothing a user can do to stop this process desolately. Take using fuel in a car, for example, it eventually runs out. However, exhausting a lithium battery takes a great deal of time and can be mitigated somewhat by user and software behaviors .
So, when a new iPhone has a 100% battery rating, it has all of the rated milliamp-hours of power available when fully charged. It also means the battery can provide enough power to the CPU at peak current draw without issue.
Apple says its batteries are designed to retain up to 80% of their original capacity at 500 complete charge cycles. A charge cycle is defined by a complete drain of the battery to zero, followed by a complete charge to 100%.
This expected battery life can vary from user to user. The average user is expected to keep their battery health north of 80% for the first two years with regular use. Hitting 80% within a year is cause for concern, and Apple will replace your battery for free with AppleCare or for a fee without.
Others who use their iPhone constantly and charge their device from near dead to 100% multiple times a day will see their battery degrade faster. Looking at your Screen Time will reveal if you’re unconsciously overusing your device — maybe it’s time to put down your iPhone if TikTok shows multiple hours of use in a short time.
Of course, iPhones are bought to be used. But, like anything, moderation is important, especially if you’re worried about something as physical as battery chemistry.
Ultimately, once the battery degrades below 80% of its original capacity, protections within the operating system will engage to ensure the device doesn’t shut down inadvertently. This throttling can be avoided by having the battery replaced at an Authorized Apple Service Provider.
After the iPhone throttles the processor for the first time to prevent a shutdown, a new toggle will appear in battery settings. This gives users the ability to turn off the throttling feature and allows the processor to draw full current.
However, the device will shut off as soon as the current draw exceeds what the battery can provide. It is highly unadvisable to turn off the throttling feature and can lead to battery damage.
Degraded batteriesBefore iOS 10.2.1 in 2017, the iPhone didn’t do much to account for aging batteries in its software. However, a perfect storm of circumstances set AppleBattery up for user complaints about inadvertent shutdowns in older devices.
Recent devices had more powerful processors, thinner designs, and brighter displays. These factors led to smaller batteries with lower capacities that died faster. A smaller battery also meant a lower peak voltage, which meant aging batteries would dip below peak rated voltages sooner.
Those factors were coupled with more people buying iPhones than ever, then keeping them for longer than expected, which led to more reports of batteries becoming exhausted. Note that the “Plus” models and iPads were not encountering shutdown issues thanks to their larger battery capacities .
Intermittent shutdowns were reported by owners of the iPhone 6, iPhone 6s, and iPhone SE. Users complained that the device would show battery levels of 30% or more then suddenly shut off as if the battery died.
This occurred because these devices’ batteries had been exhausted to the point that they could no longer provide peak power during peak CPU draw. Since there were no other protections in place, the iPhone would sense the CPU power draw exceeding the available current and just shut down to protect the iPhone battery.