What everyone is missing is this: Lithium batteries have a finite life whether you use them or not. Sure, you can extend their life by storing them at a low state of charge, but that is a pretty inconvenient thing to do, and still leads to 15% capacity loss in 4 years. Best case, you are only going to get 300-500 cycles or 3-5 years out of a battery, no matter how much you baby it. I currently have 341 cycles on my MacBook battery, and I still get 2.5 hours of life out of it on a full charge. I leave it plugged in all day at work, and then take it home asleep. It also sleeps all weekend.
I take your point, but I am not sure that the page you link to really supports your position:
It looks to me, from what they say there, that by storing my battery, most of the time, while I am running the computer off the mains, at about 40% charge level, I could pretty much double its useful life, from about two years to about the 4 that you suggest is a reasonable expectation.
Yeah, great - all you need is a telepathic charge controller!
See, most people want to USE their laptops. They don’t want to unplug the laptop from the wall (where it’s been “charging” all day), and find that they only have 2 hours of battery life when they should have 5 - because the charging circuitry was trying to maximize battery longevity! That’s why all these schemes to increase battery life are just a red herring - keep your battery full, and just put up with a 3-year lifespan. Spending $100 every three years on a new battery is only a dime a day - isn’t it worth that to actually be able to use your machine on the road without worrying whether it is fully charged or not?
Re my experience with the last 3 Li-on battery tech notebooks I’ve owned. I’ve used them plugged in 99.99% of the time. Battery life uptime after 2 years (when I sold them) was approx 55% - 65% of new. About what I would expect if not plugged in. Keeping them plugged in does not appear to negatively impact battery life vs cycling them.