My phone, a Nextel i830 (motorola) draws as much as 750mA when charging a low battery and transmitting at the same time.
I've modified the datacable to try to charge from USB, but the per-port current limit quickly kicks in and puts an end to it. As I understand it, the 500mA as per the usb 2.0 spec is only available after a device enumerates as needing that much current. The default of 100mA is all that will be allowed, unless the device specifically asks for more. I don't think my phone enumerates as a high power device, since I'm not able to draw more than 100mA. I don't think there's anything that can be done on the host side to enable more current, the limits are probably imposed at the microcode level, inside the USB host interface chip. On older computers, those having only usb 1.1 ports, you might be able to get the full 500, or more, since I don't think current-limiting routines were imposed until 2.0 came around. Just my two-cents! Gordon On 3/12/07, Ingo Rohloff <[EMAIL PROTECTED]> wrote: > On Mon, Mar 05, 2007 at 01:06:49AM +0100, Michael Mauch wrote: > > Alan Stern wrote: > > > On Sun, 4 Mar 2007, Ingo Rohloff wrote: > > > > > >> I have got a mobile phone and I want to charge the battery > > >> of the phone via the USB port. > > > > It really wouldn't have hurt to mention the brand and model of the > > phone. > > Argh, I feel stupid now :-). > It is an Sony Ericsson K800i > > > > > > > No, that isn't the problem. PCs always provide the maximum 500 mA, apart > > > from situations where the device is suspended. More likely it's the phone > > > which has to be configured to use all of the available current. > > I had a look into the sysfs entries (as far as I could find them). > There the "bMaxPower" file contained a setting of "500mA". > So maybe the problem really is, that the phone somehow has to be told > that you really want to charge with maximum charge current or > something like that. > (I guess the windows driver hopefully does that...) > On the other hand the 500mA might simply be not very much ? > > with best regards > Ingo > > ------------------------------------------------------------------------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share your > opinions on IT & business topics through brief surveys-and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > _______________________________________________ > Linux-usb-users@lists.sourceforge.net > To unsubscribe, use the last form field at: > https://lists.sourceforge.net/lists/listinfo/linux-usb-users > ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Linux-usb-users@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-users
