My iPhone's Battery Health shows a maximum capacity of 72%. Does that mean the phone can only charge up to 72%, or does charging to 72% mean I'm getting 72% of that already reduced capacity? I'm trying to understand how the percentage relates to the battery's original capacity and whether the battery may need replacing.
3 Answers
A 72% maximum-capacity reading means the battery can store about 72% of the energy it could when it was new. The phone can still charge to 100%, but that 100% is now roughly 72% of the original design capacity.
At 72% health, noticeably shorter battery life is expected. For example, if the phone originally had a 10,000 mAh battery that lasted 20 hours, it might now hold around 7,200 mAh and last closer to 14–15 hours under similar use. Replacing the battery should restore capacity much closer to its original level.
If the original battery capacity is treated as 100%, charging a battery with 72% health to 72% would give you about 51.84% of the original capacity. Charging it all the way to 100% gives you the battery’s current full capacity—approximately 72% of what it held when new.
That clears it up, thanks! So the 72% health figure is separate from the normal charging percentage.