Does It Affect an iPhone to Unplug It When It's Not Fully Charged?by Ashley Poland
It's a common myth that you must charge your rechargeable batteries until they're completely full and not charge them until they're empty. That was true for nickel-cadmium batteries, which can suffer from capacity issues when improperly charged. The iPhone uses a lithium ion battery and does not need the same care as nickel-cadmium batteries. Unplugging your iPhone before it's fully charged does not damage the battery or its capacity.
Your iPhone's lithium ion battery has a lifespan measured in charge cycles -- the number of times your battery has been charged to 100 percent and run down to zero. A charge cycle is not defined by every time you've plugged in the phone. Apple uses the following example: if you charge your battery to 50 percent on day one, deplete it and then charge to 50 percent again on day two -- that's one charge cycle. Apple recommends doing a full charge/discharge once a month, where you charge the battery to full capacity and run it down completely.
iPhone Charging Time
The iPhone uses a feature known as a fast charge, which rapidly powers your battery up to 80% in two hours, provided you're not using the iPhone while it's charging. Once you've reached 80 percent, the iPhone goes into a trickle charge, where it charges the last 20 percent in another two hours.
Battery Life Expectancy
Even with the best charging habits, your iPhone battery will eventually drop to about 80% of its original capacity. From there, the battery will continue to lose life until you'll eventually need to replace it. According to Apple, you should go through 400 charge cycles before losing battery capacity. However, other factors may cause damage to your battery and result in it losing capacity sooner.
Avoid using or storing your iPhone at extreme temperatures. Apple recommends an operating environment that ranges from 32 to 95 degrees Fahrenheit. Avoid any temperatures lower than -4 degrees and higher than 113 degrees. You should also consider removing your phone from its case, if you have one. Heat during charging can be amplified by the case, and overheating can drop the battery's capacity over time.