Advanced Configuration and Power Interface Specification

Advanced Configuration and Power Interface Specification
Figure 3-6 Re;maining Battery Life Formula
Smart Batteries also report the present rate of drain, but since they can directly report the estimated
run-time, this function should be used instead as it can more accurately account for variations
specific to the battery.
3.9.4 Low Battery Levels
A system has an OEM-designed initial capacity for warning, initial capacity for low, and a critical
battery level or flag. The values for warning and low represent the amount of energy or battery
capacity needed by the system to take certain actions. The critical battery level or flag is used to
indicate when the batteries in the system are completely drained. OSPM can determine independent
warning and low battery capacity values based on the OEM-designed levels, but cannot set these
values lower than the OEM-designed values, as shown in the figure below
Full
Last full charged capacity
F
OSPM-selected low battery warning capacity
Warning
OEM-designed initial capacity for warning (minimum)
E
Low
Critical
OSPM-selected low battery
OEM-designed initial capacity for low (minimum)
OEM-defined Battery Critical flag
Figure 3-7 Low Battery and Warning
Each Control Method Battery in a system reports the OEM-designed initial warning capacity and
OEM-designed initial low capacity as well as a flag to report when that battery has reached or is
below its critical energy level. Unlike Control Method Batteries, Smart Batteries are not necessarily
specific to one particular machine type, so the OEM-designed warning, low, and critical levels are
reported separately in a Smart Battery Table described in Section 5.2.14.
The table below describes how these values should be set by the OEM and interpreted by the OS.
48 April, 2015 Version 6.0