I suspect that it may be to do with the laptop charging system learning the upper and lower limits it has to play with. Rechargeable batteries have vastly improved over the years, the old universal rule of thumb of approximately 500 charge/discharge cycles has rapidly risen to where it is today. With more modern chargers having a two way conversation with the unit they are powering to work out how much current and voltage to supply, I suspect that the charger is throttled down when not needed, and boosted when required as well. The memory effect of NiCad batteries is a distant past with new battery technologies emerging. Think of your battery as an UPS to jump in when power is suddenly lost and you should be fine for many years plugged into the mains.
As a general comment on Acer equipment. Having worked with thousands of them over the years, I have observed if one purchases a unit with a one year warranty, then it will work reliably for one year
and ONE day, and then suddenly fail. Get one with a three year warranty, and it will fail after three years
and ONE day. They are built to very tight specifications, and due to volume, the engineering can be a work of art, where even the case design is such that where a reduction of a screw or two worth a penny can be saved, over the course of a production run of a few million units, massive savings can be made. Far more than with any other item of equipment I have seen, computing or not, you are getting what you paid for, not one penny less or one penny more.
With the recent breathless news missives of
superconductors operating at room temperatures (excluding the entire northern hemisphere with the excessive heat due to climate change will stop them from working), within a few short years laptops will be powering themselves without any external connections, the true perpetual motion machines my uncle dreamily told us about, all those decades ago, as he drew a water wheel at the outside of a boat, being turned by a constant flow of water from a spout coming from a hole in the middle of the boat that produced a geyser that flowed over the top of the wheel, thus turning it for ever from the constant flow of water. When we built a little boat and waterwheel, tried it in the bathtub, the geyser never went higher than the outside level of water the boat was sitting in, this destroying that theory, took away my childhood innocence of wonder at marvellous things, and turned me into a sly old science cynic.
Don't get me started on fusion power! The technology 'just around the corner', driven by laser beams and massive magnets trapping the super-hot plasma into a torus, to be released in 'a year or two', these promises being rolled out at excited investor forums for the last thirty or forty years at least. Go to sleep with one of those ticking away and see if you awake in terror at what could happen. BOOM!
Just a little ditty that is ironic in light of climate change warriors these days:
Perpetual Motion