WetGeek My question would be, "what's considered a charge cycle." If your unplugged laptop is at 90%, and you plug it in long enough for it to reach 100%, does that count as a charge cycle? If you unplug it and use it until it quits, and then charge it up to 100%, that's more like what I think of as a charge cycle.
I don't think that it is a precise measurement, but this explanation is as good as any:
"_A battery cycle simply refers to one full drain of a battery's charge, from 100 to zero percent. This doesn't have to happen all at once. For example, if your laptop battery drains from 100 percent to 50 percent, then you charge it back up to 100 percent and let it drop to 50 percent again, that counts as one cycle.
Battery cycle count, then, is the number of times that your battery has gone through a cycle. The lower your laptop's battery cycle count, the "healthier" its battery is. A healthy battery will hold close to its factory-maximum charge, compared to one that's been heavily used._"
As I understand it, from this and other similar explanations, a "battery cycle" occurs every time a battery is charged from drained to fully charged. 0>100 counts as one battery cycle, 50>100 counts as one half a battery cycle, 25>100 counts as three quarters of a battery cycle, and so on:
"Essentially, a charge cycle equals one full discharge down to 0% and then a recharge back up to 100%. A discharge down to 50% and then back to 100% would equal half a cycle. Over time, each charge cycle decreases a battery’s capacity from its design specifications, meaning that the fewer times you drain it, the longer the battery lasts — all other things being equal."
When plugged in a battery continues to drain, slowly but surely, because the battery needs a certain amount of energy to maintain itself. That's why some manufacturers set up a laptop so the battery won't charge until it is down to 90%. The theory is that a periodic 10% charge (10 count as a battery cycle) builds battery cycle count more slowly than having the battery charge from 99% to 100% frequently. My Latitudes do that using Windows 11, but not using Solus.
The reason that battery cycles are important is that each battery cycle uses chemical reactions and slowly lose the ability to fully charge. If you look at a battery that is several years old, it won't charge to full battery capacity. As an example, the battery in my Latitude 7390 (now two years and 6 months old, give or take) has about 85% capacity -- designed for 60AH, it now can charge only to 49AH.
