21

I have found myself in situtations where the internal battery has been used frequently. How do I check its status without diving into the mountain of directories?

NOTE I need to know about the CMOS battery. not the laptop's power supply, so this isn't a duplicate of those questions

Zanna
  • 72,312
Death_by_Ch0colate
  • 353

5 Answers5

13
$ cat /proc/driver/rtc | grep batt
batt_status     : okay
Martin
  • 131
9

use app lm_sensors:

$ sensors-detect

next , run sensors and look for Vbat value:

$ sensors
it8718-isa-0290
Adapter: ISA adapter
in0:          +1.18 V  (min =  +0.00 V, max =  +4.08 V)
in1:          +1.89 V  (min =  +0.00 V, max =  +4.08 V)
in2:          +3.31 V  (min =  +0.00 V, max =  +4.08 V)
+5V:          +2.91 V  (min =  +0.00 V, max =  +4.08 V)
in4:          +0.69 V  (min =  +0.00 V, max =  +4.08 V)
in5:          +0.08 V  (min =  +0.00 V, max =  +4.08 V)
in6:          +0.42 V  (min =  +0.00 V, max =  +4.08 V)
in7:          +2.93 V  (min =  +0.00 V, max =  +4.08 V)
Vbat:         +2.94 V  
fan1:        1713 RPM  (min =    0 RPM)
fan2:        1558 RPM  (min =    0 RPM)
fan3:           0 RPM  (min =    0 RPM)
fan4:           0 RPM  (min =    0 RPM)
temp1:        +48.0°C  (low  = +127.0°C, high = +127.0°C)  sensor = thermistor
temp2:        +39.0°C  (low  = +127.0°C, high = +70.0°C)  sensor = thermal diode
temp3:         -2.0°C  (low  = +127.0°C, high = +127.0°C)  sensor = thermistor
intrusion0:  ALARM

radeon-pci-0100
Adapter: PCI adapter
temp1:        +55.0°C  

coretemp-isa-0000
Adapter: ISA adapter
Core 0:       +56.0°C  (high = +80.0°C, crit = +100.0°C)
Core 1:       +55.0°C  (high = +80.0°C, crit = +100.0°C)
N0rbert
  • 103,263
zersh
  • 221
5

If you open up the laptop, you can use a multimeter to check the voltmeter reading of the CMOS battery. This is the only reliable way that I know of.

N M
  • 159
4

The sensors command doesn't output the CMOS battery voltage for my laptop. This article gives other pointers:

To summarize the link:

A constant beeping sound is another sign that your CMOS battery is dying. The final sign that your CMOS battery is going dead is that you'll receive an error message. The three main types of error messages are: CMOS Checksum Error, CMOS Read Error and CMOS Battery Failure.

WinEunuuchs2Unix
  • 105,762
3

It seems that it can not directly detected on many systems (rtc_cmos), because the RTC time will be corrected when the kernel is loaded and the failed oscillator flag will be reset. Then the RTC is powered by the system.

Therefore the answer of Martin doesn't work, as the result is always okay on such systems.

$ cat /proc/driver/rtc | grep batt
batt_status     : okay

But the rtc driver seems to fix the time itself, some drivers would log this to the kernel log, but even when it's not logged you could determine it by verify the rtc clock setting in the log.

$ sudo journalctl -k -g rtc.*setting
Jan 26 22:48:36 pc-4711 kernel: rtc_cmos 00:00: setting system clock to 2012-01-01T00:00:30 UTC (1325376030)
jeb
  • 137