# **Why iPhone updated to new iOS often drains battery, charges slowly** **Many users say it takes them up to 3 hours to fully charge their iPhone battery to 100% after updating to iOS 16.5.** Later When Apple released iOS 16.5 version on May 18, many users reported having battery problems. “iOS 16.5 is the version with bad battery life,” an iPhone user shared on social networks. Some other users also reported battery draining faster than usual after updating to iOS 16.5. ## Reasons why iPhone battery is low, charging for a long time after updating iOS According to *TechRadar*, battery drain error occurs very sporadically, appearing only in some cases but the problem of slow charging speed suddenly appeared on most machines. Some users shared that their iPhone took up to 3 hours to fully charge 100%. “Has anyone noticed that the battery life on iOS 16.5 is so bad,” one user posted on his personal Twitter. Another person responded: “iOS 16.5 on my device makes the battery drain faster than before, the charging speed is also too slow. The device charges with a genuine 20 W charger from 23% to 100% and takes up to 3 hours. “After a few reboots, my iPhone 13 Pro seems to be working much more smoothly but the battery life is terrible,” another user complained. *TechRadar* thinks this phenomenon is actually quite normal. Not only Apple, but other software publishers, every time they announce a new operating system update, force the device to recreate the data index file, calibrate the battery settings. This causes the battery to drain faster. This condition is only temporary and will return to normal after a few days of stable operation. ## Not Apple’s fault Apple has previously encountered similar reflections. The company recommends that users wait a few days, at least 48 hours to see if the battery life is back to normal. The process of installing a new operating system on an iPhone requires a lot of background work, which can take hours to days, said Adrian Kingsley-Hughes, a researcher at *ZDNet*. “Not only does this waste energy, but calibrating the battery settings can also give the impression that the battery is draining faster when it is not.” Calibrate the battery settings i.e. fully charge and fully discharge the battery to get the correct capacity of the battery. Agreeing with this point of view, *MacWorld*’s Jason Cross also thinks that the iPhone system is running a lot of tasks in the background such as optimizing data, rescanning images with a new machine learning algorithm, so it will cause problems. battery drain condition. Besides, the battery adjustment process is carried out by many different complex algorithms, so it is normal to have a few cycles of discharge and full charge of the battery. In addition, the new operating system version also comes with a number of updates and new features, which may drain the phone’s battery more. Therefore, according to *TechRadar*, your iPhone is just updating the system so there is no need to worry about long-term effects on the device. Users should use the phone for a few days and see if system errors such as battery drain, long full charge will disappear or not. You can also go to **Settings > Battery > Battery Status** to check. If the maximum capacity is still at 80% or more, you can rest assured this is only a temporary error when installing new iOS. In the latest iOS 16.5 update, Apple has fixed a bug that allows anyone to view the contacts in the phone from the lock screen. However, in version 16.5, Apple’s Lightning to USB 3 accessory also encountered another serious error. Specifically, as noted from posts on Apple support forums, Reddit and *MacRumors*, many users reported that the accessory suddenly became useless after updating to iOS 16.5. Lightning port does not transmit power to charge iPhone and iPad. Meanwhile, connecting the accessory to the adapter via the USB-A port will result in a power overload device error message. This port switch is very popular when it comes to connecting iPhone to other devices for features like networking or audio.