Topic: Battery not loading (Novena Laptop)

After completely discharging the battery it won't charge anymore. The behaviour is the same for an avtice/inactive laptop. Pushing the level-button the batteryboard doesn't show anything. Plugging in the AC adapter (standard HW) works for bringing up the OS. I don't think the battery got damaged..would be weird xX Anybody similar experience?

Re: Battery not loading (Novena Laptop)

Michael, If you provide the "stats" output from your battery board that may help somebody understand what is happening/happened to your battery.

Connect to the battery board (senoko) using (or your personally preferred serial program):

sudo screen /dev/ttymxc3 115200

Then press enter once to get a ch> prompt, and then enter the "stats" command

ch> stats
Manufacturer:       Texas Inst.
Part name:          bq20z95
Firmware version:   0x5009
Charge FET:         on
Discharge FET:      on
.
.
.

Paste the full output of stats here.

Re: Battery not loading (Novena Laptop)

Ah cool I didn't know this was possible. Is there any documentation for that?
This is the output:

stats
Manufacturer:       Texas Inst.
Part name:          bq20z95
Firmware version:   0x5009
Charge FET:         on
Discharge FET:      off
State:              battery failure
Time until full:    65535 minutes
Time until empty:   65535 minutes
Chemistry:          LION
Serial number:      0x0001
Charge:             0%
Max capacity:       6038 mAh
Design capacity:    5000 mAh
Temperature:        22.24357 C
Voltage:            7272 mV
Current:            0 mA
Average current:    0 mA
Target voltage:     12600 mV
Target current:     0 mA
Number of cells:    3 cells
Cell 1 voltage:     2947 mV
Cell 2 voltage:     2215 mV
Cell 3 voltage:     2111 mV
Cell 4 voltage:     0 mV
Charge status:      0x2001
    Charging allowed?   yes
    Can suspend?        no
    Can precharge?      yes
    Can maintenance?    no
    Temperature limit?  no
    Temperature limit?  no
    Can fastcharge?     no
    Pulse charging?     no
    Pulse disable CHG?  no
    Cell balancing?     no
    Precharge timeout?  no
    Fastcharge timeout? no
    Overcharge OV?      no
    Overcharge OC?      no
    Overcharge?         no
    Battery empty?      yes
Alarms:
    TERMINATE DISCHARGE ALARM
    REMAINING CAPACITY ALARM
Charge state:
    Battery initialized
    Battery discharging/relaxing
    Battery fully discharged
No errors detected
No safety alerts
Safety status:
    Pack undervoltage condition
    Cell undervoltage condition

Re: Battery not loading (Novena Laptop)

Oh dear, that's very not good.

Your battery is severely overdischarged, with all three cells below the safe lower limit of 3v. The gas gauge won't charge the battery in this state, and forcing the system to use the battery just makes it worse.

You *may* be able to get the battery voltage back up to the minimum voltage level such that the gas gauge will start managing it again, but be aware that it's going to have a severely impaired capacity.

To force the charger to do a precharge, use the following commands in the same shell as you did 'stats' in:

chg pause
chg set 500 12600

That should start slowly charging the battery. Hopefully after an hour or so the cell voltages will rise up above 3000mV and the gas gauge can be reengaged ('chg resume').

Re: Battery not loading (Novena Laptop)

The pack has gone into cell undervoltage lockout.  The charge FET is enabled, which means it can theoretically charge, and the discharge FET is disabled.

That is to be expected, as it is very, very low.  Dangerously low, in fact.  It shouldn't have been possible to get that low.  I don't know that it's safe to charge, but cell voltages are above 1.7V, so it might still be okay.  At least there are lots of protections in place.

The thing is, the gas gauge is telling the charger to not charge at all.  Which is why it isn't charging.

You can try one of two things.  First, try turning on IT.  Run "gg it".  See if that doesn't turn on the CHG FET.

Secondly, try manually charging things.

chg pause
chg set 256 12600
[wait fifteen seconds]
stats
chg resume

Give that about fifteen seconds, then check "stats" again.

Re: Battery not loading (Novena Laptop)

Ehh..ok..so there is a chance that the battery is going to explode? xX

Re: Battery not loading (Novena Laptop)

When it comes to electricity-illiterate folks like me I think some clarification between 'dangerously' and 'critically' low needs to be made.

8 (edited by michael.stahn 2015-05-01 02:51:54)

Re: Battery not loading (Novena Laptop)

xobs wrote:

Secondly, try manually charging things.

chg pause
chg set 256 12600
[wait fifteen seconds]
stats
chg resume

Give that about fifteen seconds, then check "stats" again.


Three repetitions of this manual charging re-established the normal behavior: the battery now charges normally (if it's normal that there are only 3 cells). I'm wondering what lead to this total depletion. Is the battery board online all the time? Pushing the "level" button shows the power state via leds so it seems it's active.
Another thing (not related to the batteries): the eDP adapter seems quite hot..is this normal? I'm wondering if this shortens its lifetime.

Re: Battery not loading (Novena Laptop)

The eDP chip gets warm, not hot. I think the rule is that lifetime is cut in half for every 10°C, but it's cool enough I'm not terribly concerned (though it IS kind of annoying to know it's chewing up power).

Re: Battery not loading (Novena Laptop)

Things get too hot to touch around 50-60C, which IC's will handle readily.

Re: Battery not loading (Novena Laptop)

What I think happened is this:

1) You discharged the battery to 0%
2) The mainboard shut off
3) The battery went below 9V
4) The battery board noticed this, and cut off power to the mainboard
5) The Senoko CPU stayed on, and drew about 8 mA of current (which is normal)
6) This was enough to cause the battery to drain below 7V, which caused the gas gauge to shut off power to the Senoko CPU (https://github.com/xobs/senoko-chibios- … o/gg.c#L51)
7) By the time you plugged it in again, it didn't want to do a deeply-discharged charge cycle.

I think the solution is to increase the shutdown_voltage to around 8.5V rather than 7V.  This will require loading new firmware onto Senoko (which we were planning on doing anyway.)

Re: Battery not loading (Novena Laptop)

Also, if he was running an old version of the senoko firmware then he probably hit the issue with the watchdog reset starting the system spontaneously, which would have drained his battery.

13 (edited by michael.stahn 2015-05-01 17:03:06)

Re: Battery not loading (Novena Laptop)

So the Senoko battery board DOES stay active all the time even the operating system is shut down? If yes is this a special feature of the lenovo laptop or is this also implemented in "standard" laptops? Having a 5000 mAh Battery would lead to a complete discharge in 26 days without doing anything. I wonder I have to shut the battery board down if I want to have total 0 A usage for the whole Laptop.

Re: Battery not loading (Novena Laptop)

Lenovo?

Yes, the battery board stays powered, and only uses a negligible amount of power. It happens in normal laptops too, except the gas gauge/charger IC's are built into the battery pack instead of being external, and are never powered down. If you're going to store the Novena without using it for a month or more, unplugging the battery is recommended (and trivial).

Re: Battery not loading (Novena Laptop)

What is the reason that it needs to remain active when the whole system is off?

Re: Battery not loading (Novena Laptop)

Something needs to be able to monitor the power button, otherwise you couldn't turn it back on.

Re: Battery not loading (Novena Laptop)

It needs to monitor the power button.  It also needs to control the charger, which needs to have values written to it at least once every 300 seconds or else it will stop charging.

Re: Battery not loading (Novena Laptop)

Is 8mA the consumption of all the Senoko board or only the microcontroller? Seems a bit high... is the STM32 entering sleep mode?

Re: Battery not loading (Novena Laptop)

I've always assumed 8mA is the consumption of the entire board.  Which is why you can see 8mA of current draw when not charging (use 'gg deadband 1').  But it could just be a calibration error, which is why the "deadband" command exists at all.

I don't believe the STM32 is entering sleep mode.  We had that working a while ago, but encountered problems.  Now that the system is more stable, I'll re-enable it.

Lots of bugfixes to push out in a new Senoko version.

Re: Battery not loading (Novena Laptop)

xobs wrote:

Lots of bugfixes to push out in a new Senoko version.

Sounds good (: