Linux – Notebook’s Battery is not calibrated. Operates at 0% for an hour

batterylaptoplinuxpower supplywindows

My problem is that even if the battery percentage is 0 the notebook can stay on around an hour.
I have disabled "critical battery action" on my operating systems to use more time my notebook.
The designed capacity is 66 Wh, the battery currently reports 9 Wh when battery is full.

I tried to fully charge the battery (around 5 hours) and then let the battery drain completely.
That increased the full energy value from 3 Wh to 9 Wh.

Is there any way to trully fix the full capacity value of the battery?

I think that the battery's problem occured from my previous faulty power supply.

My notebooks is Dell Inspiron 3521.
Operating Systems: Ubuntu 14.04 based & Windows 8.1

Battery Details:

Vendor : Simplo
Model : DELL 4DMNG31N
Energy : 9,2 Wh
Energy When Full : 9,2 Wh
Energy (design): 66,6 Wh
Voltage : 12,2 V

More Info Requested:

The battery is 1.5 years old, the previous battery after a year was dead ("Battery has experienced permanent failure" message at boot) and Dell send me a new one. The power supply some times couldn't charge the notebook and sometimes gave less watt than 90 that my notebook needed (problem with the cable, just received a new one from Dell too) Bios doesn't have any utility for the battery.

Best Answer

All I can say is re-calibrate the battery. here's how :)

  1. have a way to keep track of time. this can be done with a stopwatch or even a phone (IOS & android both have that function built in, android has an app called stopwatch, IOS 7-9 has it in the clock app).

  2. charge the battery all the way to 100% (simple enough)

  3. take note (on a piece of paper preferably) of how long the computer estimates the battery will last (this will make the later steps easier)

  4. tweak the battery settings so the display will never shut off and set the critical and low battery actions to none

  5. open the stopwatch app (or just get it out if you have a physical one) and start it the moment you unplug the battery being sure to not touch the computer and ignore all battery low and battery critical notifications.

  6. stop the stopwatch as soon as the computer shuts off and record that time.

  7. calculate the difference between the 2 times

  8. do steps 1-7 once more so you have 3 results (a. the computer's estimate, b. test 1, c. test 2)

  9. charge the battery once more and record the computer's new estimate and compare it to the 2 tests, hopefully the computer's estimate will be more accurate then before.

The reason the battery get's un-calibrated is because the is a little microchip in the battery compartment that measures the voltage of the batteries (which are only a set of 18650s by the way).

I don't know if that's entirely correct, but if you need more info, check out this video by "the 8-bit guy" (formerly "the IBook Guy") (https://www.youtube.com/watch?v=iy9Mp1vik-s).

If you need a new battery, you can try rebuilding one. the same guy from the previous video also did a video on this topic (he's doing it to an I-Book G3 Clamshell, but the same technique can be done to almost every other laptop battery) (https://www.youtube.com/watch?v=VrDnTXqoqjM)

hope this helps :)

Related Question