0

Just installed Elementary OS on my Macbook pro (2010) with the battery on full charge. I boot up elementary and suddenly I'm told it's on 7%. Granted, my battery is horrendously weak (1hr to reach 0% on macOS), but the charger is always connected and indicating that the battery is at 100%. When I remove the charger though it legitimately seems like the battery is 7% since it decreases every 3 mins (as seen on MacOS), and once it reached zero it requested that I remove the installation device and press enter (consequently shutting off the mac). Without plugging in the charger I boot the device (this time to macOS) and it tells me the battery is at 33%??? Multiple google searches got me nowhere. Anyone has any idea what's wrong?

0

There isn't anything "wrong", per se. This is just a matter of elementary OS using different math from Apple. Let's look at how these two OSes can show different numbers for the same hardware.

Note: As I'm not sure whether you're using a 13" or 15" MacBook Pro, I'll use the battery specifications for the 15" model from 2010.

First, let's take a look at what sort of statistics your battery has to offer with upower:

upower -i `upower -e | grep 'BAT'`

This will give you something like the following:

native-path:          BAT0
  vendor:               SMP
  model:                45N1149
  serial:               3126
  power supply:         yes
  updated:              Thu Aug  5 04:14:40 2021 (106 seconds ago)
  has history:          yes
  has statistics:       yes
  battery
    present:             yes
    rechargeable:        yes
    state:               fully-charged
    warning-level:       none
    energy:              43.93 Wh
    energy-empty:        0 Wh
    energy-full:         43.96 Wh
    energy-full-design:  56.16 Wh
    energy-rate:         38.691 W
    voltage:             12.197 V
    percentage:          99%
    capacity:            78.2764%
    technology:          lithium-ion
    icon-name:          'battery-full-charged-symbolic'

Note: This battery output is from a Lenovo Thinkpad W541. Yours may look different.

When macOS is determining your battery life, it looks at the energy and energy-full values to determine how much life remains, while elementary OS (and many other Linux derivatives) look at energy and energy-full-design. With this in mind, let's do some math.

A 2010-era 15" MacBook Pro notebook usually ships from the factory with a 63.5Wh battery. 7% of that would be about 4.45Wh.

OS Calculation   Value
MacOS energy / energy-full 4.45 / 4.45 100%
elementary OS energy / energy-full-design 4.45 / 63.5 7%

For many Debian-based Linux distributions, the "critical battery shutdown" takes place at 2%. That works out to about 1.27Wh.

OS Calculation   Value
MacOS energy / energy-full 1.27 / 4.45 28.539%
elementary OS energy / energy-full-design 1.27 / 63.5 2%

If we take into account the energy rebound that takes place after a battery stops discharging momentarily (as well as Apple's propensity to use round, "people friendly" numbers whenever possible), we can consider the 33% value that macOS reports as a rounding error.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.