Do you charge your phone 100% all the time? If you are, then you might be actually damaging the battery and reducing its lifespan. It may put your mind at ease when your smartphone’s battery reads 100 percent charge, but it’s actually not great for the battery. A lithium-ion battery doesn’t like to be fully charged.
Typically, a modern phone battery’s (lithium-ion) lifespan is 2 – 3 years, which is about 300 – 500 charge cycles as rated by manufacturers. After that, the battery capacity will drop by roughly 20%. You can often observe that your phone usually charges quickly from 20-80% but, from 80-100% it usually takes more time than expected. Some research shows that after 80 percent, your charger must hold your battery at a constant high voltage to get to 100 percent, and this constant voltage does the most damage.
If you’re on a device that runs iOS 13 or later, you are lucky because Apple’s new Optimized Battery Charging option allows you to do exactly this. When the feature is enabled, your iPhone will delay charging past 80% in certain situations. Your iPhone uses on-device machine learning to learn your daily charging routine so that Optimized Battery Charging activates only when your iPhone predicts it will be connected to a charger for an extended period of time. The algorithm aims to ensure that your iPhone is still fully charged when unplugged. That said if you can avoid getting full to the brim on a regular basis you can actually extend your battery’s lifespan! Another reason to let your phone be while it's re-energizing in peace is that using your phone while charging - especially for intensive tasks like watching videos or gaming - can disrupt the charge cycle and reduce battery life too.
That said, if you can avoid getting full to the peak on a regular basis, the practice will pay dividends in the long run. If you can live with an energy band of about 80 percent instead of 100 percent, you can easily increase the battery life. For most of the time, if you are at home/ office and you have a charger right next to you it is recommended to charge your phone upto 80% but, if you are heading out and you know that you need that extra juice, it is better to charge upto 100%. Whether you are charging 80% or 100% batteries degrade and reduce capacity over time. Lastly, but perhaps most importantly, your phone is not going to last forever.