Linux

There’s two things you might be talking about here:

The old way of making sure nickel cadmium batteries didn’t degrade, which was to discharge them all the way and charge them back up all the way. Your new laptop is almost certainly using lithium ion batteries which are chemically “damaged” more through that process than just leaving them plugged up all the time.

You could be talking about the old way of dealing with charge controllers, where the controller relied on the bios or os to tell it what to do and didn’t “know” how to respond to batteries at different stages of charge. This hasn’t been the situation for like fifteen years. Nowadays charge controllers go “yup, ready to go boss, 12345mah of charge, 90%” when some bios or os polls them.

You don’t even need to manually keep your battery in the 20-80 range nowadays since almost every charge controller automatically monitors temperature and adjusts charging parameters to not damage the battery. It’s not like the old days where the charge controller was just an ic controlling a fet acting as a slucegate between the battery and the power brick.

Heck, lithium ion batteries nowadays last longest the longer they’re plugged in. Running them to <10% every charge cycle actually diminishes battery life!

Tldr welcome to the future, don’t worry about it!

It should never be needed, even when replacing the battery as that data is part of the BMS.

Calibration was a thing like 25 years ago with the awful NiCD/NiMH batteries as I remember.

Not an expert but: tldr don't.

Battery calibration is supposed to help the battery's firmware figure out how low the battery can go. It also tends to hurt your battery, so you should avoid performing these calibrations and keep the charge between 20% and 80% as much as you can.

It seems what you're trying to do is improve battery estimation by the OS on a new machine. And in that case, ~~Is just trey trip love~~* I'd just try to live with possible insecurity of not knowing whether the machine has 15 or 25 minutes left.

• Thanks, auto-correct!

The charge controller's idea of what's going on is totally independent of what's going on in the CPU. It doesn't know and doesn't care about your OS.

Multiple calibration cycles are pointless. Doing it once (every few months) should be enough. Or doing it never is fine too. I had one laptop (thinkpad l480) that would get out of calibration, such that the charge controller would go straight from 45% charge to 1%.

What's happening is that lithium batteries have a very steady voltage for most of their usage. The voltage mostly changes at the top and bottom ~%10 of charge. Everything else in the middle is guesswork - the charge controller has to measure and count every drop of current going in and out of the battery. Measuring consists of a current meter - you put a very low value resistor in line and measure microvolts of drop across it. You can have a high precision current meter, or you can have one that "doesn't burn a lot of power in the dropper resistor", not both. Some systems have too inaccurate a meter. Some have phantom draws that aren't well accounted for (like the battery's own internal resistance and drain). If the battery spends all of its time in the "voltage never changes" region, the current counter's guess will diverge from reality.

When you discharge/recharge the battery, you are forcing its current counter to realign itself with reality. Whatever it thinks is left in the battery, nope that's really zero when we drop to ~3.2 volts.

The battery state should be controlled by the firmware, which is independent of the installed OS, so a calibration should not be needed

Afaik in almost all cases the battery monitors work independently of the OS (on the BIOS level I guess) so you should only do the calibration if you notice issues with the monitoring and not more often than like once a year. Also if the battery is very worn out, there's no way to get accurate measures.

That should be handled in firmware if I remember correctly.