| 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 7.1 |