Trust me, I was using it semi-sarcastically too. This thing is slower than my old Pentium 4 would be, yet has a fast enough 30% to 3% battery discharge rate that it would make the speed of light itself blush.

The main culprit is that anyone estimating battery life in percentages. It's about voltage and current draw. The battery voltage can be read directly.

About being slow, I suppose it does run windows and its infamous 'defender'

> The main culprit is that anyone estimating battery life in percentages.

I thought this was a solved problem, like, decades ago? At least I remember even the first gen MacBooks having accurate battery percentages, and it’s a more vague memory but my PowerBook G4 did too I think.

The "accurate" charging level mostly happens with specific amount of charge cycles (i.e. new). Laptop batteries suffer from higher temperature (over 60C), overcharging (over 4.22 per Li-Ion for most chemistries).

No, I think it's fairly easy to see that a third of the charge suddenly disappearing is a fairly uncommon behavior.

Same for your Windows idea...

"A third" is again fraction/percentage - it's still a representation stuff that depends on charge and charge cycles... and likely previous over charging and heat (Li-Ion doesn't like heat).

To put it simply: the charge level, usually, is just a lookup table for voltage (not under load).

In case it was somehow magically unclear, it's not that I don't understand how batteries work, but that either that exact charge approximation mechanism is working exceptionally incorrectly, making it appear as if the battery suddenly lost so much charge, or the battery is a bust.

I do not know whether the battery is actually experiencing that sudden loss in charge, nor do I care, because in practice the end result is the same...