Force faster charging

[cheapie]

Is there a way to force the charging circuit to draw 1A (or whatever) from a port that is capable of delivering that much? (Without using a USB-Barrel Jack adapter)

 

[EvilDragon]

I've no idea - MWeston or notaz should know that.

 

[ashcloud]

echo 1000 > /sys/devices/platform/omap_i2c.1/i2c-1/1-004b/twl4030_bci/power_supply/twl4030_usb/charge_current

seems to raise the current limit to 1000mA. I just don't know what's the maximum useful number to write in there.

 

[mcobit]

But make sure to set it back after charging or risk damaging your PCs usbport when hooking it up for masstoragesession the next day.

 

[notaz]

echo 1000 > /sys/devices/platform/omap_i2c.1/i2c-1/1-004b/twl4030_bci/power_supply/twl4030_usb/charge_current
seems to raise the current limit to 1000mA. I just don't know what's the maximum useful number to write in there.

No it doesn't, charge_current is not in mA but in some nonlinear units, you have to read /sys/class/power_supply/bq27500-0/current_now and check what it was actually set to. Also you should use /sys/class/power_supply/twl4030_usb/charge_current and not that long path above as it might change on future updates.

I also don't recommend changing this, yet more using large values, the charging chip starts to heat significantly and that might reduce it's lifetime or even burn it.

 

[urjaman]

The units for range 1023-512 are roughly (value-512)*3.32mA. The TPS65950 datasheet will have an exact(er) formula. The 512 is a bit setting CGAIN, so values 0-511 are roughly half of the values in the upper range (value*1.66mA).

So 1000 is roughly 1620mA. I would not recommend doing that. If you want 1A out of usb the correct value is roughly 810. Also, the USB port is rated for 1.1A max, so I'd say dont exceed that with usb.

EDIT: Also, I'd say that above about 1.2A the time for a full charge is not that much affected. The charge will reach 4.2V earlier but the fill up phase will take longer. (== the constant current phase will be shorter while the constant voltage phase will be longer). Of course if your battery is dry and you want the maximum amount of charge in a limited time... it will void your warranty (i think I've voided my warranty so many times over that I cant count them anymore ), but atleast my pandora has survived charging at 1.7A - your mileage might vary...