On 9/12/2013 4:42 PM, John Andersen wrote:
Where does this thing get its battery state measurements?
The widget in the taskbar as well as the plasma thingie on the desktop indicate 32% while the battery level in KSysGuard indicates 68%.
Why would two utilities from the same release of KDE differ about the state of the same battery?
Answering my own question.... For the Google Spiders: (Pardon my pedantry) KSysGuard appears to be calculating its capacity based on last full charge capacity. The Widget is basing its charge on the Design Capacity. On an older battery, there will be a significant difference between the two. An old battery will never charge to its design capacity. KSysGuard's calculation is more accurate for any given age of battery. Example: (from my Aging Dell Inspiron 9400) poulsbo:~ # cat /proc/acpi/battery/BAT0/info present: yes design capacity: 4800 mAh <------- Full Capacity when new last full capacity: 2388 mAh <------- Full capacity today. battery technology: rechargeable design voltage: 11100 mV design capacity warning: 480 mAh design capacity low: 145 mAh cycle count: 0 capacity granularity 1: 48 mAh capacity granularity 2: 48 mAh model number: DELL F51336 serial number: 883 battery type: LION OEM info: Sanyo Today, the charge circuitry shut down when the battery reached 2388 mAh. This "Full charge" occurs when the battery reaches the voltage threshold and the current drops to three percent of the rated current. (The charging current drops as the battery gets closer to a full charge due to increasing battery resistance) A battery is also considered fully charged if the current levels off and cannot go down further. Old Batteries will simply not charge to their design capacity. KSysGuard reports your battery percent full by measuring the current remaining charge compared to the last known "Full Charge". So it is reporting the percent of battery life in your battery compared to a "Full Charge" given your battery's capabilities as the are today not as they were when the battery was new. So after a "Full Charge", my ancient dell battery reports this as soon as I start using the battery poulsbo:~ # cat /proc/acpi/battery/BAT0/state present: yes capacity state: ok charging state: discharging present rate: 3047 mA remaining capacity: 2226 mAh <-------- This is all I can expect these days. present voltage: 11906 mV KSysGuard reports that as 93% capacity. (2226 / 2388 * 100) The Battery Widget on the other hand reports that as 46% capacity based on original "factory full charge" 2226 / 4800 * 100. So BOTH KSysGuard and the Widget are correct, they are just measuring different things. The widget's calculation method is use by the power management settings to decide when the computer should sleep, or shut down or hibernate, because this gives a more consistent expectation of battery capacity (minutes) remaining, allowing for a proper shutdown. 2% of design life is consistently mappable to minutes. 2% of current life is a shrinking window. Ricardo: You were closer to right than you realized. ;-) -- _____________________________________ ---This space for rent--- -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org