Watt Support?#

Tue, 02 Oct 2007 23:53:00 +0000

I wrote

Battery query: I have the 3 cell battery for this machine, which is labelled as 28Wh @ 10.8V - so I calculate the expected capacity as 2.55Ah

However, /proc/acpi/battery says the "design capacity" is 1481 mAh. Actual battery life is ~2h30, but the system indicates 0% at 1h30-2 hours, so I don't know when to save work and hibernate. I have tried (twice) a full charge and discharge to calibrate the battery as described on your web site, but it has had no effect.

 # fully charged, and with the ac adaptor connected 
dan@toy:~$ sudo cat /proc/acpi/battery/C1B6/* 
alarm: unsupported 
present: yes 
design capacity: 1481 mAh 
last full capacity: 1481 mAh 
battery technology: rechargeable 
design voltage: 10800 mV 
design capacity warning: 75 mAh 
design capacity low: 15 mAh 
capacity granularity 1: 100 mAh 
capacity granularity 2: 100 mAh 
model number: Primary 
serial number: 29392 2007/02/10 
battery type: LIon 
OEM info: Hewlett-Packard 
present: yes 
capacity state: ok 
charging state: charged 
present rate: 528 mA 
remaining capacity: 1467 mAh 
present voltage: 12337 mV 

How do I make the capacity gauge work? Linux kernel version is Linux toy 2.6.22-2-686 #1 SMP Fri Aug 31 00:24:01 UTC 2007 i686 GNU/Linux

HP replied

Dear Daniel,

Thank you for contacting Hewlett-Packard's Commercial Solutions Center.

This is with reference to your e-mail regarding the HP Business notebook Nc2400.

From the information provided in your e-mail, we understand that the Battery is not providing the optimum performance

We would like to inform you that we do not support Linux Operating system because of which we would not have any idea regarding the capacity gauge.

We would like to inform you that different Operating systems and its functions would consume different amounts of battery power. For e.g. with Windows XP installed, the battery should provide 2.5 hours of backup. While with the Vista Operating system, it would be 1 - 1.5 hours. This is subject to the number of applications running and devices that are connected to the notebook.

In order to check for the battery you could download and install the battery health test from the following web-link:

http://h20239.www2.hp.com/techcenter/battery/battery_ts.htm?jumpid=reg_R1002_USEN

This would only work for the Windows XP version.

I have a suggestion: if you do not support Linux (and I suppose I shouldn't have been misled by the claim on your web site to be "the global enterprise open source and Linux leader" into believing that you might), then do not provide it as an option on your web form for submitting support requests. Actually, I have another suggestion: learn to read and write English, and then maybe you'll be able to (a) address the issue (design capacity apparently misreported) instead of fobbing off with "we would not have any idea", and (b) understand the correct use of the word "because".

In the meantime, http://www.notebookreview.com/default.asp?newsID=3537 seems to describe a similar problem, albeit on different hardware