> not charging or using the battery at all once it is done charging, without me having to physically remove the battery Most flagship devices already do this.

> not charging or using the battery at all once it is done charging, without me having to physically remove the battery Most flagship devices already do this. They automatically enter kiosk mode after being plugged in for a few days which eliminates the spicy pillow problem by keeping battery voltage significantly lower than normal. Eg https://support.apple.com/en-gu/HT208710 https://support.apple.com/en-gu/HT208710 > I thought this is how laptops used to work Transients are a problem for laptops and desktops too. Eg: - Macbooks go into limp mode by asserting PROCHOT when the battery is <10% (or disconnected or high internal resistance) regardless of whether the laptop is plugged in. If they didn't, a sudden increase in power usage would cause enough voltage sag to reset the machine or cause data corruption. See https://apple.stackexchange.com/questions/380493/cpu-throttling-on-macbook-with-bad-battery-and-catalina https://apple.stackexchange.com/questions/380493/cpu-throttl... - An RTX 3090 draws only 350W, but transients are often double that. A lotta people with weak PSUs and aggressive OCP had random reboots and bluescreens until they upgraded their PSU. The newer RTX 4090 has a better VRM which causes smaller transients so it can work with a smaller PSU despite having a 450W TDP.