On 8/10/09, Wolfgang Spraul <wolfg...@qi-hardware.com> wrote: > Rask, > I guess it comes down to price. > Most normal end users won't need the current measurement as they > don't do development, so adding an extra chip to do the measurement > either in the device or in every battery might not be worth it. > > Maybe in the device just run a wire to the 3rd battery pin, then sell > it with a non-Coulomb counter battery normally, and offer the > Coulomb-counting battery as an add-on for developers? > > Thanks a lot for your excellent feedback, we need to study this more... > Wolfgang > > On Sun, Aug 09, 2009 at 01:37:00PM +0200, Rask Ingemann Lambertsen wrote: >> On Mon, Aug 03, 2009 at 01:46:26AM +0800, Wolfgang Spraul wrote: >> > How are people really using the Coulomb counter in gta02? >> > Theoretically I would think that it provides far superior power >> > measurement >> > options for actual software development, just as you write. >> > For example when playing with power saving codes, whether in the kernel, >> > middleware or applications, I would think over the course of several >> > hours or >> > days the Coulomb counter data is the primary means for efficient >> > development. >> >> To me: The clearly most useful part of the bq27000 is the current >> measurement. You get what seems to be a reasonably accurate measure of the >> current flow to/from the battery updated every 25 s or so. It's much more >> practical than an external ammeter: No need to open the case and fiddle >> with >> probes, you can measure battery current while in the train, at work or >> wherever. Having it built in makes accurate current measurement available >> to >> many more people in a lot more places. >> >> Here's a few examples where the current measurements have proven >> useful: >> 1) Tracking down that current leak from the serial ports into the Calypso. >> 2) Finding that 8 mA apmd current leak Debian used to have. >> 3) Confirming the X.org server screen blanker current leak of 38 mA. >> 4) Measuring the effectiveness of reducing CPU clock and core voltage. >> >> Hopefully it will also help to curb assorted forms of spyware because >> they will be easier to detect with the power consumption figures readily >> available. >> >> I don't think it is worth it to spend a coulomb counter on each >> battery. >> The selling point would be to keep track of battery degradation, but I've >> already seen it change its mind from 1067 mAh to 1148 mAh - that's an >> error >> of two hours worth of idle time at 100 MHz. >> >> To get a charge level reading, add a voltmeter connected to the battery >> terminals. As long as the charge and discharge rates are moderate, it will >> be good enough.
Well, for me user experience when using CC battery is much better when using dumb battery. I just tested dumb battery on my gta02 yesterday, and it works fine... but seeing percentage growing up without any charger connected isn't thing which normal user wants to see ;) -- Sebastian Krzyszkowiak dos _______________________________________________ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community