Strange Apm And Battery Behaviour On C1000

[Gatu]

Hi,

I found a rather strange behaviour at my C1000:

When I suspend it (by the  menu on the X-screen) even after beeing fully charged  and try to resume after some days then it won't resume properly.
If I connect the charger then after some minutes it will be able to boot (no explicit reset necesary.)
It seems that the battery was completely empty because also the time settings are lost.
So something seems to draw the battery empty while the device is suspended because self discharge will not empty it in some days. There are beside the SD card no other cards inserted.

Also if I use it normally with battery it will show 100% ..... 50 % .... one step more (I do not remember which) and then it is suddenly empty. Result: see above.

The battery and the Zaurus are new, I run Pdaxrom beta3.

Is this behaviour normal? Is there any work around?

Thanks,
Gatu

[CktRider]

Have your new battery checked.

The last battery I purchased would drop from about 50% capacity to zero in a very short time.  I saw some similar behavior to what you describe, and decided it was the SL-C1000 performing normal shutdown procedures under low-battery conditions.  When I had the new battery checked by my vendor, he indicated it was bad and provided me with another new one.  The problems then vanished.

[Gatu]

The battery is the original one... the problem is that I did not buy the Zaurus locally but through the internet so I cannot just go to the store and ask them to check... And I do not want to send it back while I am not sure that it is really broken.
I will observe some days more.
Is there some software which can log the state of the battery? I do not look at the battery icon all the time so I do not know exactly the behaviour just before it is empty.

Br,
Gatu

[Drake01]

Is there some software which can log the state of the battery? I do not look at the battery icon all the time so I do not know exactly the behaviour just before it is empty.
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If you type apm at the command line, it will print the system's assessment of your battery level (100%, 85%, etc.).  You could write a simple cron job to log these to a file, along with a timestamp, at regular intervals.  This should provide you with some idea of how fast your battery is fading.

I don't know if there is a command that will provide you with anything like actual voltage or current.

[Gatu]

I observed the Zaurus while discharging. Until 38% everything was ok. Then I went away 10 minutes and when I came back it was off. After charging some minutes I could resume it, so obviously it did not just turn off but rather suspend. Dmesg shows something about battery (fatal event or similar).
Is it possible that the filling state of the battery is shown wrong?

Br,
Gatu

[Gatu]

Hi,

now I used a script which I found here: http://ldrolez.free.fr/software/zaurus/ to log the battery discharge. I had do do some modufications to make it work on pdaxrom
I began to run it after I disconnected the fully charged C1000 from the charger. The CPU frequency was at normal speed. Screen blanking etc turned of. No software beside X-server (with panel etc) and the logging script running. No cards beside the SD-card inserted.

The battery lasted 298 minutes (= almost 5 hours) in this conditions.
Is this time normal in this conditions?
Everything went very slow until 43 percent, then it keeped during 6 minutes 38 percent, then in ten minutes it dropped to zero percent and the device suspended.

There is one number taken from cat /proc/driver/battery/sharpsl_main_battery_voltage which seems to represent the battery voltage. It starts at 216, then remains between 200 and 190 for a long time and at the end drops to 178 in the last minutes.
Basically the discharge curve of the battery seems to be quite flat and then drops sharply and the kernel does not seem to take this really in account.

Br,
Gatu

[Gatu]

Something interesting:

echo 2 > /proc/driver/battery/msglevel make the dmesg quite verbose about battery issues, this may be interesting for troubleshooting.
echo 0 > /proc/driver/battery/msglevel will revert to normal.

Br,
Gatu

[pelrun]

I did some battery testing today...

/proc/driver/battery/sharpsl_main_battery_voltage can be converted to a true voltage by dividing by 51 (the MAX1111 A/D used is 8-bit with a 5V reference). A full battery will be at about 4.2V (214), with the AC attached too it will show max about 4.3V (221).

/proc/apm refuses to give a charge level with AC attached, so you can use sharpsl_main_battery_voltage to give you a vague idea of what point the charging is at without unplugging. I say vague because a LiIon cell will only be 70% charged  when it first reaches the "full" voltage, and charging will continue at that voltage for the remaining 30%.

Anyway, with AC disconnected, the voltage will go down roughly linearly until about 3.65V (186), at which point there's only 17% runtime remaining; the voltage then plummets to reach 2.8V (143) at 0% runtime remaining. At that point the protection circuit in the battery cuts the power to the Z.

So to get a reasonable percentage value, at least for my battery:

volt = value from /proc/driver/battery/sharpsl_main_battery_voltage
if (volt >= 186)
{ percent = (volt*83 - 14843) / 35 }
else
{ percent = (volt*17 - 2431) / 43 }

I'll have to try this with the BL-08 and third-party batteries I have to see what difference age or capacity makes. I'm hoping it just changes runtime and not the shape of the curve, but without data I'm just wildly guessing at this point...

Edit: AUGH! Had 414 instead of 214, and used it instead of 221 in the original math. Fixed now (and made more integer-math friendly.)