Funny battery values (nx6325)
robert.moore at intel.com
Wed Mar 17 16:28:10 UTC 2010
>From: owner-freebsd-acpi at freebsd.org [mailto:owner-freebsd-
>acpi at freebsd.org] On Behalf Of Joerg Wunsch
>Sent: Wednesday, March 17, 2010 9:19 AM
>To: freebsd-acpi at freebsd.org
>Subject: Re: Funny battery values (nx6325)
>As Kevin Oberman wrote:
>> FWIW, IBM/Lenovo recommend that, should the battery capacity stuff
>> get messed up, you FULLY discharge the battery and then re-charge.
>I'm doing that right now with my TP 600E battery, too. It was
>completely dead (one out of the three cell pairs had 0.0 V), so I
>replaced all cells by some other 18650 cells I've got around. While
>the machine yelled "Battery critically low" after only about 5 minutes
>of run-time, it already lasts for half an hour now. I hope I'll also
>be able to re-train the Coulomb meter chip in the battery there.
>> This is claimed to re-initialize the values stored in the battery
>> and I found this worked on a battery in my old 600E. Mine did not
>> have a weird "Design Capacity" value, though.
>Same here, the "Design capacity" of that TP 600E battery makes sense,
>unlike on the nx6325.
>As Ian Smith wrote:
>> > > Is this consistent or does it vary from boot to boot or if you
>> > > disconnect and reconnect the battery?
>> Or try another battery?
>Only got that one. The machine is normally a semi-desktop one.
>> > That's right, but it wouldn't be supposed to affect the "Design
>> > capacity", would it? ;)
>> It wouldn't be supposed to :)
>> Tracing back through acpi_cmbat_get_total_battinfo in acpi_cmbat.c
>> indicates that calculaing remaining time does uses last full
>> capacity, but from there back through acpi_cmbat_get_bst and
>> acpi_cmbat_get_bif it's all just retrieval, from acpi packages of
>> _BST and _BIF
>Thanks for the analysis!
>> Most of it must be stored in the in-battery chip, but I don't know
>> where specs may be, or even whether they all use same protocols.
>I think this is all called the "Smart Battery specification", which is
>essentially a layer on top of a standard I²C bus. I once looked at it
>lightly in connection with a battery control IC as I did build my own
>battery (out of used 18650 cells, again) for a ham radio transceiver.
>But I haven't really looked into the Smart Battery specs so far, as my
>transceiver didn't want to talk it anyway. ;-)
There are two types of batteries, the "Smart Battery" and the so-called "Control Method Battery".
AFAIK, by far, the control method battery is dominant. Smart batteries are rare.
The file acpi_cmbat.c refers to control method batteries, I don't think smart batteries. Support for these batteries usually requires another driver, I would imagine something like acpi_smbat.c.
>> Peter's factor of 10 sounds plausible.
>Except for the design capacity value.
>> You can dump your ASL (see Handbook for instructions) and search for
>> something like:
>Thanks for that hint, I'll do it as soon as the machine is back here.
>cheers, J"org .-.-. --... ...-- -.. . DL8DTL
>http://www.sax.de/~joerg/ NIC: JW11-RIPE
>Never trust an operating system you don't have sources for. ;-)
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