Acer C720 battery hassles

gurucubano

Hello,
I own since 2015 an Acer C720 which works like a dream and fulfills all my needs. After some years the battery seemed to go to EOL. It went down from 100% to 50% in 2 hours relatively linear, and then from 50% to zero within a few minutes. So, what? I just bought a new battery (the dealer claimed "Acer original"). This showed on first boot 100% and lasts for around 4,5 hours, After this, it charged only to 78% and the amber light turns blue, but the battery level shows 78% only. During the next few days this maximum went up day by day by 1%. And while working it lasted yesterday from 88% to 12% four hours and the rest was consumed within 2 minutes.  What does this mean, that the maximum does not reach 100% ?
Thanks, Matthias

Commodore_1995#

A slight variation in voltage is acceptable. Even the battery you have installed is compatible with your notebook, see:

MaClane

Good Morning gurucubano !

Being a new battery, did you calibrate the cells?

gurucubano

I booted the C720 without power supply attached, it showed 100%, and I let it drain until power-off. Then I plugged-in power and it charged only until 76%. Anything else I should have done or do?

MaClane

CALIBRATION AND BATTERY RESET

First, disable Quick Start in the power options and disconnect the notebook from the power outlet.




BATTERY CONTROLLER RESET
Access the device manager and look for the "acpi-compatible control method battery driver" and "Microsoft AC Adapter" and give it up.
Then restart the notebook for Windows to reinstall and remove any errors.




Process to reset the battery

    Disconnect the power adapter.
    Locate the hole to reset the battery in the bottom of the computer.
    He inserted a small clip into the hole. Hold the reset button for 05 seconds.
    Let the computer rest for 5 minutes without power.
    Plug in the power adapter and turn on the system.




External Battery Pack

If your notebook has an external battery, proceed as follows:
1- Unplug the appliance from the mains and then disconnect the battery.
2- Press the power button for thirty seconds, so that the static power is dissipated.
3 - Replace the battery and turn the unit on.

Process for calibrating the battery

For this, you must turn off the device and give a 100% charge.
Then unplug and use the battery until the battery runs out.
Reload it as before.
Repeat the process 3 times so that all cells are fully calibrated.

gurucubano

You guide looks like for Windows (my Acer C720 does not run Windows) and your photo from its bottom part does not look like an Acer C720.

MaClane

gurucubano disse:

You guide looks like for Windows (my Acer C720 does not run Windows) and your photo from its bottom part does not look like an Acer C720.

Really!
Your device uses Chrome OS.
I was targeting another user with the same problem and I ended up performing the wrong post.
My apologies for that!
As for the battery reset, the video created by Acer just to inform.
But all the sparks have such a hole in the back, not always in the same position.

Commodore_1995#

Verify this links:
https://us.answers.acer.com/app/answers/detail/a_id/51932#_ga=2.8516534.203756701.1523479791-1187228471.1523479791
https://community.acer.com/en/discussion/553149/c730-chromebook-battery-no-longer-charging

gurucubano

The is no hole in the back of the Acer C720, see the foto below. The device was running ChromeOS when it came from Acer, but is today running FreeBSD and Ubuntu.

gurucubano

This page https://sites.google.com/a/chromium.org/dev/chromium-os/developer-information-for-chrome-os-devices/acer-c720-chromebook has a view from below in an open Acer C720. Maybe you're talking about the switch with the number 5. I will open the device and will have a loook what kind of switch this is...

gurucubano

Also videos about battery replacements like this https://www.youtube.com/watch?v=hyQNHqQh6gw , do not mention any additional switch or hole to press.

Commodore_1995#

check this: https://askubuntu.com/questions/217895/the-battery-indicator-power-setting-panel-shows-wrong-battery-state

gurucubano

I booted the Acer C720 yesterday from an external USB disk with an Ubuntu 18.04. The tools there show the same values:

/sys/class/power_supply/BAT0/uevent:
POWER_SUPPLY_NAME=BAT0
POWER_SUPPLY_STATUS=Unknown
POWER_SUPPLY_PRESENT=1
POWER_SUPPLY_TECHNOLOGY=Li-ion
POWER_SUPPLY_CYCLE_COUNT=0
POWER_SUPPLY_VOLTAGE_MIN_DESIGN=10800000
POWER_SUPPLY_VOLTAGE_NOW=12293000
POWER_SUPPLY_CURRENT_NOW=0
POWER_SUPPLY_CHARGE_FULL_DESIGN=3920000
POWER_SUPPLY_CHARGE_FULL=3900000
POWER_SUPPLY_CHARGE_NOW=3137000
POWER_SUPPLY_CAPACITY=80
POWER_SUPPLY_CAPACITY_LEVEL=Normal
POWER_SUPPLY_MODEL_NAME=AP13J3K
POWER_SUPPLY_MANUFACTURER=SANYCor
POWER_SUPPLY_SERIAL_NUMBER=0001

/sys/class/power_supply/BAT0/voltage_min_design:
10800000

/sys/class/power_supply/BAT0/voltage_now:
12293000

I think this battery is just broken (i.e. old). even if the dealer claims it is new and original from Acer

Commodore_1995#

I do not see anything wrong here! In my opinion, you should calibrate the battery!

gurucubano

How should I calibrtate it? I have only Ubuntu or FreeBSD on this Acer C720, no Windows, no ChromeOS, and no hole in the bottom case as someone suggested :-)

Commodore_1995#

Verify here my friend: http://manpages.ubuntu.com/manpages/xenial/man8/power-calibrate.8.html

gurucubano

Does this tool power-calibrate(8) from Ubuntu does anything with the battery itself and will it after reboot to FreeBSD have the battery fixed or does it only fix the "impression" in the Ubuntu kernel about the capacity of the battery? If not, it's useless for me, because I use my Acer C720 with FreeBSD. In any case, I will bring up this tool power-calibrate(8)  in the FreeBSD groups to see how the FreeBSD community thinks about "battery calibration" (what ever this means). Thanks for the pointer.

Commodore_1995#

You can also calibrate the battery manually, that is, by fully charging it with the notebook off and then use the notebook uninterrupted until it shuts off!

gurucubano

Can you please give an exact procedure to do it manually? Like:

1. switch it off
2. charge until full (how I do know that it is charged fully?)
3. switch it on without power supply
4. let it consume all energy until it goes off

The problem is in (2). Well, I did this already more than once. It charges only until ~80%

Commodore_1995#

2) Let the battery charge fully until the blue light appears!

gurucubano

I did so. When it was down (after consuming all energy of the battery), I plugged in the power, rebooted and now it charges only up to 75% and the LED turns from amber to blue. I know this already, in the following days of usage this percentage of this "LED=blue full point" will go up day by day around 1%, i.e. tomorrow 76%, the day after 77% ... etc.

Commodore_1995#

Can you still replace the battery with the dealer?