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Ask HN: How can I get data on watt-hours power use per day from my MacBook?

20 points by 35mm ↗ HN
There is a voltage readout, so is there a simple utility that will record how many wH / day my Macbook uses?

8 comments

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mardiyah
Using the ioreg CLI utility?

It is included with Apple's developer tools.

In the registry, Apple stores lots of hardware data, including information about your battery usage

adamrmcd
Wow, this utility is insane.

Looks like some raw data the OP can use is available here:

  ioreg -l -r -n AppleSmartBattery
35mm
Perfect, this is what I was looking for!
kbouck
if plugged in and at 100% at the start of the measurement, wouldn't a simple kill-a-watt give a decent per-day measurement?

if you are looking to get the measurement data in the computer, then this isn't for you...

killingtime74
This is the only right answer. if you get the data from inside your computer it will not take into account conversion losses in the transformer and the true usage at the plug
nicolaslem
Solution without any tool: lookup online the battery size of your specific machine, charge to 100%, unplug it and count how long it takes of normal usage to deplete.

Nitpick, watt-hour is a unit of energy, not power. Also watt-hour per unit of time is basically a convoluted way to describe watts.

srvmshr
Minor additional info: From System Information, note the maximum capacity, instead of the designed spec-sheet capacity (with use, always a smaller number than mint condition) and use that as 100%. Battery wear gets to be factored in then.