Two days ago, my HP laptop’s battery was working perfectly fine. Then I had to unplug the AC adapter and do stuff with the laptop elsewhere, so the battery was completely discharged afterwards. Then, I charged it again, but when going to bed I unplugged the adapter again when the battery was around 50% charged.

Fast-forward to the next afternoon, when I’m going with my family to celebrate stuff, and I turn on the laptop while in the car. Linux resumes from hibernation fine, and I see my KDE desktop again, with the battery meter at 50%. I check the Wesnoth.org forums for spambots as usual, fire up my IRC client…

And then the battery meter drops to 0%, KDE warns about suspending to disk in 5 seconds, and the laptop’s front panel battery status LED starts flashing.

I assumed that the laptop had just gone bonkers like it’s done before and ignored the warnings of imminent failure. Just as I was mentioning the ongoing problem on IRC, the laptop shut down completely, as it ran out of power.

It seems that this battery has finally collapsed, since the maximum charge dropped dramatically afterwards, and even the BIOS software warned me about it on the next boot. Here’s what acpitool has to say about the poor thing:

$ acpitool -B
  Battery #1     : present
    Remaining capacity : 704 mAh, 100.0%
    Design capacity    : 9000 mAh
    Last full capacity : 704 mAh, 7.822% of design capacity
    Capacity loss      : 92.18%
    Present rate       : 0      
    Charging state     : charged
    Battery type       : rechargeable 
    Model number       : 25 mAh
    Serial number      : Primary

(Note: Linux has always reported 9,000 mAh as the battery’s design capacity since day zero. This information is incorrect, and the correct value should be 4,000 mAh. Also note the bogus model/serial information.)

Since this is a rather critical situation, I’m probably going to buy a new battery for the laptop soon — besides sending it away for maintenance, which is in my list as soon as I buy that external hard disk drive on which I’ll be able to fit a complete raw disk image of my laptop’s HDD.