We plugged in an XO-1.0 with an unknown state LiFePO4 battery (may have been fully discharged a week before, or may have been shut down properly) and the battery LED flashed instead of coming on solid like charging normally does. The battery information in /sys indicated low battery voltage (5.something) but otherwise good health and charging state. We tried the battery in a different XO-1.0 and the same behaviour resulted. We left it plugged in overnight and it appears to have charged normally and the battery now runs the laptop (when it was doing the flashing charge, the laptop would switch off immediately when you unplug the charger).<br>
<br><a href="http://wiki.laptop.org/go/Power_management#Battery_LED">http://wiki.laptop.org/go/Power_management#Battery_LED</a> indicates flashing on charge means trickle charging. Sadly we didn't find this page when it was happening so cannot fully confirm it was flashing orange and with the 4 blinks, pause pattern. This page also doesn't give any clues as to why a battery might be trickle charging.<br>
<br><a href="http://wiki.laptop.org/go/Hardware_specification#Battery">http://wiki.laptop.org/go/Hardware_specification#Battery</a> suggests that the battery has a <a href="http://wiki.laptop.org/images/e/e9/DS2756.pdf" class="internal" title="DS2756.pdf">Maxim DS2756</a> chip in it, but this chip only monitors one cell, so I guess there are two such chips? The /sys interface only gives information about the whole battery, it doesn't tell you about the state of each cell. The specification pdf on the Hardware_specification page describes the Embedded Controller interface to the operating system in terms of "Battery", not "Cell" so I guess it doesn't expose each cell either?<br>
<br>Is it possible to see each cell's voltage separately from within the operating system or the open firmware? I guess if there is no other way, it wouldn't be terribly hard to program a microcontroller to talk to the cell monitors over the 1 wire bus.<br>
<br><br clear="all">Kind regards<br>Tabitha Roder<br>