Ubuntu – How to get the correct battery status


At this moment, ever since I installed Ubuntu on this machine, the battery status says: not present.

Looking at this answer, however, I find that /proc/acpi/battery/BAT1/info (sometimes its /proc/acpi/battery/BAT0/info, use tab complete to help) has the following info:

present: yes
design capacity: 4400 mAh
last full capacity: 4400 mAh
battery technology: rechargeable
design voltage: 11100 mV
design capacity warning: 300 mAh
design capacity low: 132 mAh
cycle count: 0
capacity granularity 1: 32 mAh
capacity granularity 2: 32 mAh
model number: BAT1      
serial number: 11        
battery type: 11        
OEM info: 11        

In accordance to this answer, I've checked the /proc/acpi/battery/BAT1/state file:

present:                 yes
capacity state:          ok
charging state:          charged
present rate:            unknown
remaining capacity:      unknown
present voltage:         10000 mV

The acpi -b command returns:

Battery 0: Unknown, 0%, rate information unavailable

Any suggestions on getting the battery info updated?

Best Answer

The acpi -b error you have reported most probably indicate an ACPI type issue.

ACPI is an open-standard for device and power-management.

Some laptops (most googled that I found were Acer) incorrectly report its battery details to Ubuntu. I'm not sure of your laptop type and model - nor its BIOS version.

Sometimes you need to compile your own kernel with a fixed DSDT table.

Sometimes you need to upgrade your BIOS to the very latest offered by your manufacturer.

If you decide on the latter action you should remember that updating the BIOS of a motherboard or laptop is always a risky operation, because if something goes wrong, the risk of irreparably damaging the hardware is very high.

You will need to follow the instructions for BIOS updates from your manufacturer.