K-3iii and in-camera battery recharging

altis wrote:

Just avoid extended periods sat above 80% or below 25%. Otherwise, use as is convenient.

https://batteryuniversity.com/article/bu-808-how-to-prolong-lithium-based-batteries

really interesting article. My initial read suggests the following for longer battery life:

1. It's not a problem charging the LI90 frequently, and probably better to do that than use one to exhaustion before replacing. So plugging in the camera in the evenings shouldn't be a problem.
2. On the final day of use, don't top off the battery for storage--leave it at a reduced charge. If carrying the camera and a spare battery, swap out the main battery for the spare (without charging the main), for the last day/session, so that neither is stored at full charge.

Past that, it's hard to translate the information into operational rules such as "above 80% or below 25%" without better instrumentation or documentation on the camera itself. For example:

At what charge level does the status screen battery indicator actually indicate a low charge?

What does 'low' actually mean? The only terms the manual generally uses are insufficient, low, and full or fully charged. None of these terms are actually defined either technically or operationally AFAICS.

How accurate is the charge level icon? For example, at what level of charge does the battery no longer read full? If the icon shows 'half full' (say two little fill indicators down, but not indicating low charge yet), what's the actual charge level? My experience with the K-3 was that it would indicate it was fine/full until suddenly it wasn't--there was really no way to know "okay, I'm at 35% charge." And the final fill indicator on the battery icon went away much faster than the first did--the icon didn't seem reliably linear.

At what level of battery charge does the USB charging turn off? The manual says it turns off when "fully charged" so I assume that means 100% I don't know any way to charge to 80%, nor really any way to estimate remaining charge in percent-of-fill.

Suppose a battery is at 100%, but I've just returned from a trip and know I won't need it for a while why I process trip pictures. How would I de-stress it (reduce to say 75% charge) for storage?

Perhaps this is all a bit obsessive, but I do try to take care of my gear as best I can. I had a laptop that was usually/generally/always plugged in at home, and it became totally useless for the road. Working capacity unplugged dropped down to maybe 10 minutes simply because I almost always had it plugged in. My new laptop provides a way to avoid that by limiting/shutting-down charging even when plugged in. I wish I had the same level of control with the camera.

Anyone have the PF ebook? Does it add any useful information here?