ACPIBAT(4) | Kernel Interfaces Manual | ACPIBAT(4) |
The battery status is made available through the envsys(4) API. The battery information can be displayed also with the envstat(8) command:
$ envstat -d acpibat0 Current CritMax WarnMax WarnMin CritMin Unit present: ON design voltage: 14.400 V voltage: 16.267 V design cap: 74.880 Wh last full cap: 48.260 Wh charge: 47.910 5.000% 0.414% Wh (99.27%) charge rate: N/A discharge rate: 16.641 W charging: OFF charge state: NORMAL
Depending on the battery, the unit of measurement is either watt-hour (Wh) or ampere-hour (Ah) for the capacity related information. From these the “charge” is usually the most interesting value, but it is possible to derive useful information also from the other values. For example, when acpiacad(4) is disconnected, the “discharge rate” gives a coarse approximation of the current power consumption. The ratio between the design capacity and the last full capacity on the other hand reveals the overall “health” of deteriorating lithium-ion batteries.
March 17, 2010 | NetBSD 6.1 |