[Bug 255] New: battery voltage scale is not correct
bugzilla-daemon at bugzilla.openmoko.org
bugzilla-daemon at bugzilla.openmoko.org
Sun Mar 11 14:44:24 CET 2007
http://bugzilla.openmoko.org/cgi-bin/bugzilla/show_bug.cgi?id=255
Summary: battery voltage scale is not correct
Product: OpenMoko
Version: current svn head
Platform: Neo1973
OS/Version: Linux
Status: NEW
Severity: normal
Priority: P2
Component: kernel
AssignedTo: tony_tu at fiwin.com.tw
ReportedBy: laforge at openmoko.org
CC: sean_chiang at fic.com.tw
Since we don't have a coulomb-counting battery gas gauge, we cannot give proper
battery metering.
Our current battery percentage reading is based on battery voltage, and uses a
linear scale between 2.8 and 4.2V (see drivers/i2c/pcf50606.c:battvolt_scale()).
This scaling is obviously wrong and just a 'proof of concept' scale.
Somebody needs to do proper charge/discharge measurements and come up with a
non-linear algorithm expressing estimated battery life based on present battery
terminal voltage.
This needs a lot of experimentation/measurement, as well as a couple of
calculations. Please provide me either with a patch against battvolt_scale(),
or give me a mathematical formula expressing battery lifetime percentage as
function of terminal voltage.
------- You are receiving this mail because: -------
You are on the CC list for the bug, or are watching someone who is.
More information about the buglog
mailing list