On an Apple OS X system, such as a MacBook Pro laptop, the command
pmset
-g rawlog displays an ongoing log of battery state as read
directly from the battery. When the system has external alternating
current (AC) power, the value for external connected
is "yes". If the battery is 100% charged, battery charging
is "no".$ pmset -g rawlog pmset is in RAW logging mode now. Hit ctrl-c to exit. * Battery matched at registry = 12803 external connected = yes battery present = yes battery charging = no cap = 3839/3839 time remaining = 1092:15 current = 0 cycle count = 194/1000 location = 0
If I disconnect the power cable, pmset will periodically update its display showing me the current status for the battery, including the estimated time remaining on battery power.
$ pmset -g rawlog pmset is in RAW logging mode now. Hit ctrl-c to exit. * Battery matched at registry = 12803 external connected = yes battery present = yes battery charging = no cap = 3839/3839 time remaining = 1092:15 current = 0 cycle count = 194/1000 location = 0 2/2/16 9:45:29 PM EST external connected = yes battery present = yes battery charging = no cap = 3839/3839 time remaining = 1092:15 current = 0 cycle count = 194/1000 location = 0 2/2/16 9:46:24 PM EST external connected = no battery present = yes battery charging = no cap = 3839/3839 time remaining = 1092:15 current = 0 cycle count = 194/1000 location = 0 2/2/16 9:46:54 PM EST external connected = no battery present = yes battery charging = no cap = 4209/4209 time remaining = 3:03 current = -1377 cycle count = 194/1000 location = 0 2/2/16 9:47:25 PM EST external connected = no battery present = yes battery charging = no cap = 4209/4209 time remaining = 2:47 current = -1509 cycle count = 194/1000 location = 0 2/2/16 9:47:55 PM EST external connected = no battery present = yes battery charging = no cap = 4209/4209 time remaining = 2:45 current = -1528 cycle count = 194/1000 location = 0
In the above output I can see that the estimated time remaining for battery power doesn't necessarily match the amount of time that has elapsed since the last update was displayed. E.g. at 9:45:25 the time remaining value was 2 hours and 47 minutes, yet at 9:45:55, 30 seconds later, the estimated time remaining has been decreased by 2 minutes. The above readings where the "cap" value was x/x, e.g., 4209/4209, were displayed at times the battery capacity display at the top of the screen was reading 100% When the value displayed at the top of the screen for the OS X GUI dropped to 95%, I saw the following:
2/2/16 10:01:06 PM EST external connected = no battery present = yes battery charging = no cap = 4004/4209 time remaining = 2:20 current = -1716 cycle count = 194/1000
I.e., the capacity reading was then x-y/x. Plugging the power cable
back in changed the battery present and battery
charging values to "yes".
