Rich Mingin (PLUG) via plug on 30 Apr 2020 17:44:40 -0700

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Re: [PLUG] Acer Chromebook 14: 18% battery loss in a year?

What you're seeing is battery wear, or charge/discharge cycles, and it has very very little to do with the CPU or your use case of the system. What it *does* relate to is how many times the laptop battery has been discharged and recharged. Lithium Ion batteries aren't magical, they're a fairly simple chemical reaction at the gross scale, and like all chemical reactions, things don't ever quite return to the original state. Imagine water that you freeze into ice cubes and then allow to melt in an empty glass. After a couple of cycles, you'll notice the ice cubes are smaller, because water is lost to evaporation while the ice is melting. Your laptop battery has a similar issue, but it's the graphite anode in the battery cells that "evaporates" a tiny amount each time the charge/discharge cycle happens. Once the graphite anode has been worn down, it has less usable surface area for reactions, so the battery capacity drops. Once it drops enough, you no longer have any usable run-time. You might see this in very old and heavily used laptops, where you unplug the laptop from the wall and the screen instantly winks off. This is because the battery, even at maximum charge, is not providing the expected voltage for any amount of time. The graphite anode breaks down *very* rapidly past a certain amount of wear.

16% is a lot of wear for a year, but not unreasonable. It is reaching the point where it will impact your usable battery run time, though. You can replace the battery with a new one to get full capacity back. Otherwise it's a one-way process. Do NOT follow any Facebook or Googled "wisdom" about One Simple Trick to restore capacity, though, they are all quacks, nothing you do in normal use is capable of physically recreating the anode rod.

If you minimize full charge/discharges, that can help a bit, and not keeping the battery at levels significantly above/below ~70% charge can help. Do not follow advice to unplug your laptop when the charge reaches 100% or to charge to 100 and discharge to 0% multiple times over a few days or similar. As noted, these will *not* restore the chemically reacted parts, and may in fact make the problem more severe.

All is not hopeless, though. Recently most laptops have started shipping with various "smart" battery techniques. I have a gaming laptop that does not charge or discharge the battery as long as charge level is between 60-100% (configurable) and the AC is connected. While it would be even better to physically remove the battery and store it somewhere that's cool and dry, I'll take a little cure over none at all.

On Thu, Apr 30, 2020 at 7:16 PM Floyd Johnson via plug <> wrote:
This morning, after suspending my GalliumOS-outfitted Chromebook and
unplugging it, I found the "battery remaining" at 79% upon restore,
rather than the 98% that usually happens when I do that.

Xfce Power Manager clued me in that the fully-charged level is now 36.4
watt-hours versus the 44.7 watt-hours when it was new.

Granted, I've been using this rig to develop standalone apps (mobile
productivity-ware and 3-D games) and stream media, but suddenly, I have
a feeling I'd pushed the whole system harder than what it was meant for.

The upshot: Even with an N3160 CPU (Braswell System-on-a-Chip), I don't
think the Acer CB3-431 (board id EDGAR) makes it for a long-term,
high-intensity (Android Studio and Unity3D) development rig.

On the upside, the keyboard and casing are intact after a year of use -
that HP Stream 14 I had in 2018 bombed out in those departments.

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