Nice discussion on the follow mails, but i've a doubt<br><br><div class="gmail_quote">On Sun, Aug 2, 2009 at 7:07 PM, Paul Fertser <span dir="ltr"><<a href="mailto:fercerpav@gmail.com">fercerpav@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Hi,<br>
<br>
This is a text version of the wikipage [1], feel free to ask new questions<br>
there on the talk page. Discussion on this ML is also appreciated (and<br>
in fact i'm more comfortable with ML than the wiki).<br>
<br>
Openmoko devices<br>
Battery questions and answers<br>
<br>
NB: Some of the described behaviour depends on the kernel, the<br>
relevant code was pushed on 02 Aug to andy-tracking<br>
<br>
<br>
Hardware capabilities<br>
<br>
Q: What batteries can be used with gta01 and gta02?<br>
A: Original OM gta01, gta02, Nokia BL-5C, BL-6C and compatibles.<br>
<br>
Q: Do other BL-5/6C compatible batteries fit?<br>
A: If the battery is thicker than BL-6C, you won't be able to close<br>
the back cover.<br>
<br>
Q: What is the difference between all those types?<br>
A:<br>
<br>
Capacity:<br>
gta01, gta02 - 1200 mAh<br>
BL-5C old (newer/new) - 850 (970/1050) mAh<br>
BL-6C - 1150 mAh<br>
<br>
Temperature control:<br>
gta01, BL-5C, BL-6C - thermistor<br>
gta02 - bq27000<br>
<br>
Special features:<br>
gta02 - accurate and sophisticated reporting of capacity,<br>
time_to_full, time_to_empty, temperature and battery current during<br>
both charge and discharge thanks to bq27000 (aka Coloumb Counter)<br>
<br>
Q: What are hardware capabilities of gta01 and gta02 with regard to<br>
battery management?<br>
A:<br>
<br>
gta01: charging all battery types, measuring temperature with<br>
battery-integrated thermistor (currently charging and measuring<br>
temperature for non-gta01 batteries doesn't work due to the kernel<br>
driver issues but it's software limitation), measuring battery output<br>
voltage, very inaccurate and noisy measuring of battery current<br>
<br>
gta02: charging all battery types, measuring battery output voltage,<br>
communicating with bq27000<br>
<br>
Q: Can nokia phones use/charge gta01/gta02 batteries?<br>
A: gta01 and gta02 batteries will fit wherever BL-6C fits but they<br>
can't be charged in nokia phones unless you isolate the middle pin<br>
from the battery and connect a resistor of ~50k (actual measured value<br>
on a cold (25C) battery is 75k, on a slightly warm battery - 82k) from<br>
it to the ground (to fake a thermistor presence).<br>
<br>
Q: Can third-party chargers charge gta01/gta02 batteries?<br>
A: The "good" ones will most probably require the same trick needed<br>
for nokia phones. More cheaper ones are more likely to ignore<br>
thermistor absence.<br>
<br>
Q: I have several compatible batteries. What are the storage<br>
requirements for them?<br>
A: Keep in a dry cool place charged to no more than 75%.<br>
<br>
<br>
Safety issues<br>
<br>
Q: Do OM devices control temperature to stop charging if the battery<br>
gets too hot?<br>
A: No (probably gta01 does, need to check).<br>
<br>
Q: Isn't it dangerous?<br>
A: No, since all batteries (not raw cells!) have an integrated<br>
protection circuits.<br>
<br>
Q: Can i use that fancy 2800 mAh BL-5C-compatible battery i saw on<br>
ebay?<br>
A: Unless you want an explosion in your pocket i wouldn't recommend<br>
using any battery that is not produced by a reputable vendor and<br>
widely tested. And even reputable vendors make mistakes, nokia once<br>
had to recall 46 million batteries manufactured by Matsushita (<br>
<a href="http://batteryreplacement.nokia.com/batteryreplacement/en/advisory-2007.html" target="_blank">http://batteryreplacement.nokia.com/batteryreplacement/en/advisory-2007.html</a><br>
).<br>
<br>
Q: You say that BL-5C is compatible with my gta02. Does that mean i<br>
can use that BL-5C-compatible bat i bought for a buck from a bum?<br>
A: You bet, go ahead.<br>
<br>
<br>
Charging<br>
<br>
Q: My battery charges to 100% but then charging stops and the battery<br>
keeps discharging, wtf?<br>
A: LiIon batteries don't like to be kept fully charged, so the charger<br>
stops as soon as charging current becomes less than threshold. If you<br>
have GSM on it will discharge the battery.<br>
<br>
Q: But why doesn't it ever stop charging on my device?<br>
A: The GSM modem is connected directly to the battery terminals so if<br>
it's active, charger will think it's still charging the battery and<br>
won't turn off unless GSM becomes inactive. The default threshold is<br>
about 16mA, the latest Qi increases the threshold to ~32mA.</blockquote><div>Is this true for gta02 deevices only or it's the same for gta01? <br></div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<br>
<br>
Q: Does it mean if i leave my phone plugged it will eventually fully<br>
discharge the battery?<br>
A: On gta02 the charger will restart the charge automatically once the<br>
battery voltage reaches ~4V which corresponds to ~76%. Not sure about<br>
gta01, requires more investigation. :-/<br>
<br>
Q: Ok, how to make sure my battery is fully charged before a long<br>
trip?<br>
A: Replug the charger, it will trigger charging no matter what the<br>
current capacity is.<br>
<br>
Q: My power/aux LED indicates charging/discharging/whatever, what does<br>
that mean (aka why it's still blue even after i unplugged the<br>
charger)?<br>
A: Ask FSO guys about it, some of them think that the user shouldn't<br>
really know what's happening and therefore they do some special<br>
mangling of "status" sysfs node before presenting it to the user. If<br>
you want to make a decent bugreport please add clear steps to<br>
reproduce and /sys/class/power_supply/battery/uevent contents for all<br>
relevant states.<br>
<br>
<br>
Using compatible batteries with gta02<br>
<br>
Q: So, how do i use "dumb" batteries with my freerunner?<br>
A:<br>
<br>
First you need to unbind bq27000 driver:<br>
echo bq27000-battery.0 > /sys/bus/platform/drivers/bq27000-battery/unbind<br>
<br>
Then you load the dumb battery driver:<br>
modprobe gta01_battery<br>
<br>
If you need to use bq27000 driver again, do:<br>
rmmod gta01_battery<br>
echo bq27000-battery.0 > /sys/bus/platform/drivers/bq27000-battery/bind<br>
<br>
If you use Enlightment you might need to restart it after that.<br>
<br>
Q: Is capacity reported for dumb batteries accurate?<br>
A: During discharge it should be pretty (+-10%) accurate, during<br>
charge the capacity reported is ~20% more than real.<br>
<br>
Q: Why does /sys/class/power_supply/battery/charge_full says i have a<br>
850 mAh battery no matter what i use?<br>
A: It's a workaround to make popular battery gadgets work with this<br>
driver.<br>
<br>
<br>
This Q&A were prepared by<br>
Paul Fertser <<a href="mailto:fercerpav@gmail.com">fercerpav@gmail.com</a>><br>
Joerg Reisenweber <<a href="mailto:joerg@openmoko.org">joerg@openmoko.org</a>><br>
<br>
[1] <a href="http://wiki.openmoko.org/wiki/Battery_Questions_and_Answers" target="_blank">http://wiki.openmoko.org/wiki/Battery_Questions_and_Answers</a><br>
<font color="#888888">--<br>
Be free, use free (<a href="http://www.gnu.org/philosophy/free-sw.html" target="_blank">http://www.gnu.org/philosophy/free-sw.html</a>) software!<br>
mailto:<a href="mailto:fercerpav@gmail.com">fercerpav@gmail.com</a><br>
<br>
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</font></blockquote></div><br>Regards,<br clear="all"><br>-- <br>___________<br>Rafael Campos<br>o0 Methril 0o<br><a href="http://openblog.methril.net/">http://openblog.methril.net/</a><br>