I’m only about a month into using Manjaro (specifically, KDE Plasma) on an ASUS X556 laptop / Intel Core i7. As I was adjusting some power management settings, I noticed the battery and brightness menu also provides a battery health measurement.
Not having seen this measurement before, I’m curious how this measurement is calculated. Additionally, is it a component of KDE Plasma? Manjaro itself?
This is done at a lower level, and the battery itself forwards the information to the kernel/desktop/widget.
Some BIOSes (UEFI) also have additional battery health checks and optimizations that are OS-independent.
For reference, some manufacturer’s batteries are considered to meet the requirements as refurbished if it still retains 80% or more of its original rated capacity.
Keeping an Li-ion battery “healthy” is an unfair catch-22:
The more discharge-recharge cycles it goes through, the more it wears out the cells. (The deeper the discharge-recharge, the worse!)
However if you leave it indefinitely plugged in at 100%, it essentially keeps the battery at a high “stress” level (think “high pressure” in a water tank.)
Of course, if you never use the battery, well, then you’re not getting you money’s worth out of it.
I’ve found the best results with: never charge an Li-ion battery beyond (self-reported) 80%, and to not let it drop below 40%. This works splendidly for phones, but it’s not as feasible with a laptop for obvious reasons. (“Never” is a strong word. Perhaps “only when really necessary”.)
Using a cheap USB fan to keep the battery cool during recharge also helps. (Doesn’t hurt to have one placed on your night-stand or desk, and turn it on to blow air over the phone as it’s charging.)
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