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Comment by notemaker | Hacker News Reader

In my experience, the damage of not stopping at 80% is minimal. Perhaps it is more related to the quality of the battery / hardware surrounding it?

I have not been particularly kind to my battery, but all the same my Samsung Ativ Book 9 Plus from 2012/2013 still has 83% capacity and can live for about 4-5 hours browsing/reading/programming.

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I am not a battery expert, but my understanding is that the most significant way that batteries degrade is through the heat production when charging near capacity (say 80-100%). This is why high end laptops like macbooks or thinkpads have battery management hardware/software that never automatically charges the battery to 100%.

For instance, based on recommendations by TLP, my thinkpad internal battery only charges to 60% and external to 75%.

> This is why high end laptops like macbooks or thinkpads have battery management hardware/software that never automatically charges the battery to 100%.

Here:

> Software may limit charging above 80% when the recommended battery temperatures are exceeded

https://www.apple.com/ca/batteries/maximizing-performance/

I recall seeing another document on apple.com (that I can't find) that described the behaviour where leaving a macbook plugged continuously cycles between back and forth charge and discharge between something like 90-96% to avoid trickle charge and prevent wear due to heat.

Anecdata: my work laptop has been basically stationary and therefore plugged in for the best part of the last three years, and the battery is in outstanding condition. My personal one has been mobile more often but still plugged in for extended durations, and at four years old its battery is in a similarly awesome condition.

The definition of 80% (or 0 or 100) is up to the manufacturer, so the apparently same charging behavior may have vastly different effects on the cells.

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