Please explain like I'm five: if continuously charging and drawing power at 100% hurts my laptop's battery, why doesn't the laptop bypass the battery circuitry, keeping it idle, and use the incoming juice directly?
The same happens with your battery. If you charge it to 100% a lot and leave it there then it gets "stretch marks" and the permanent defects affect how long the battery lasts.
I'm boycotting laptops until this gets fixed
I’m not unhappy with that…so I am always a bit skeptical of these laptop plugged in all the time are bad claims because it just doesn’t match my recent experience.
"In terms of longevity, the optimal charge voltage is 3.92V/cell"
https://batteryuniversity.com/article/bu-808-how-to-prolong-...
That maps out to roughly 65% charge state. So a little trickle charge on/off doesn't really help things much at all. You simply need to keep the battery in a lower charge state while plugged in for longer periods.
As bad as this is alone, the toxic combo that kills a plugged in laptop's battery in a year or two is regularly pushing it hard at full charge.
…for you. For me, I am perfectly content with the algorithm deciding, and then me, deciding when I know I am going to be disconnected outside of my normal usage pattern…telling the machine to charge it to a 100%.
But the key point is that the battery will drop to 99% very quickly and on it's own because no battery can keep the energy in perfectly. So it's recharged for the missing 1% over and over again which causes the damage.
Unless some smart charging logic prevents that, see other comments here.
Edit: typo
However, keeping "a lot" of energy in the battery is kind of the purpose, no one is using 50% max to increase battery life. But I guess most damage increases exponentially with energy stored, so charging it from 95% to 100% will damage it a lot more to than charging it from 90% to 95%.