Why it takes faster to charge from 0 to 50% then from 50% to 100%?

[bj097]

Just wondering. It's said it takes 30 minutes to charge to 50% but it obviously takes much longer to charge from 50% to 100%. Why isn't it 30 minutes too? Is it the nature of the chemistry of battery that makes it impossible to have proportional charging time?

 

[now i see it]

All lithium ion batteries can accept more current during charging when they’re mostly discharged vs getting near full.
It has to do with what’s going on inside the battery. High current when nearly full shortens the battery’s ultimate life span.
Don’t worry, Apple undoubtedly has world renown experts making millions of bucks designing the charging algorithms for their gadgets.

 

[bj097]

All lithium ion batteries can accept more current during charging when they’re mostly discharged vs getting near full.
It has to do with what’s going on inside the battery. High current when nearly full shortens the battery’s ultimate life span.
Don’t worry, Apple undoubtedly has world renown experts making millions of bucks designing the charging algorithms for their gadgets.

I'm not worried. I'm just wondering. I wish the charging speed would even faster in the future. Now I need to charge the phone twice every day on occasional gaming