Has your iPhone ever dropped to 1% and then remained there for an unusually long period of time without turning off? There is a reason for this.
It must be a revelation to know that this behavior is not limited to iPhones, and virtually any rechargeable device can exhibit it. Many users get baffled that their phone does not know how much charge is left in the battery. Nothing is analyzing the chemistry within the battery and reporting it to the phone. Instead, the phone, including any electronics built into the battery, can only make an educated guess based on what it observes at the battery terminals over time.
For example, it could keep track of how much charge it has used since the battery was last fully charged and subtract that figure from the most recent battery capacity. However, this most recent capacity figure is also an estimate based on the previous usage.
Is it true that there is only 1% left, or is it being used to scare you into charging?
One simple explanation for why 1% might last a long time is that the phone underestimated the current battery capacity. Then, when the phone reaches what it believes to be almost empty, displaying 1%, it discovers that the battery can hold more than expected. Before the battery reaches its minimum output voltage, it indicates that it is indeed empty. In fact, the algorithm designers understand that it is preferable to underestimate capacity and have the battery run out unexpectedly. Hence, the tendency is to err on the pessimistic side, with any unexpected capacity being a bonus.
In practice, the algorithms used to estimate usage and current capacity are complex, and they differ between models and battery manufacturers. Allowing the phone to re-calibrate the algorithm using a full discharge/recharge cycle can often help improve the estimate, at least temporarily. Even so, this assumes that the battery is still functioning normally. As the battery nears the end of its life, the charge varies in ways that the algorithms do not anticipate, so the percentage displayed can be a long way out regardless of what happens.
As it so happens that the battery capacity decreases as it deteriorates. The difficulty is interpreting the voltage level as a percentage of the remaining battery capacity because other factors influence the number. For example, if you use an iPhone in freezing temperatures, a portion of its battery will be unavailable until the temperature rises. In addition, if you’ve had your iPhone for a long time, the battery may be in poor condition because lithium-ion batteries deteriorate chemically over time.
This decrease in performance results in issues such as shorter battery life and causes a slow rate of app launching, lower frame rates, lower speaker volume, and incorrect battery percentages. That’s why your iPhone’s battery life can drop from 90 percent to percent in less than an hour.
So, while companies such as Apple develop complex algorithms to calculate the remaining battery life, they aren’t perfect. In fact, they frequently underestimate the amount of battery life remaining just in case. As a result, it may appear that your iPhone drops from 100 percent to 90 percent faster than it does from 30 percent to 20 percent. Despite the fact that the battery decreases by 10 percent in both scenarios, the algorithm discovers additional power surge towards the end of the discharge cycle. It is primarily because of capacity underestimation.
While in some cases, your iPhone will reach one percent with plenty of juice left in the tank. As a result, that last percent provides unusually long usage before the device shuts down.
Apple also explained many years ago that their algorithm masks the higher and lower 5 percent of battery capacity because phones and computers will cycle through minimal charges and discharges to maintain battery health when plugged in, and people would suspect a problem with the phone if it went from 100 percent to 95 percent while plugged in. It was also due to batteries in the lower section not liking being fully discharged. So, indicating the 1 percent level earlier than expected would encourage people to recharge sooner, thereby preventing some battery decay.
Although there’s not much that to do as it’s all math and algorithm, here are a few ways to extend your iPhone’s battery life and performance:
- Maintain the most recent iOS upgrade. Every major upgrade brings new features for preserving and extending battery life.
- Keep your phone in temperatures ranging from 16 to 22 degrees Celsius on average. Anything above and beyond this may be harmful to your lithium battery.
- When charging, avoid generating too much heat. Some cases or surfaces can cause your phone to overheat, resulting in battery damage. Check it while it’s charging to make sure it’s not overheating.
- Keep your phone partially charged. Emptying the battery ultimately may cause it to go into deep discharge, resulting in significant damage. The drain from a fully charged battery may have the same effect.
- Enable auto-brightness. The brightest screen settings tend to drain your battery quickly, forcing you to cycle through charge cycles and lose battery health quickly.
- In Settings > General > Background Refresh, look at your background activity. Running too many apps in the background tends to drain your battery.