1226856 - Option to Enable / Disable charging via USB when connected to PC

Status: RESOLVED WONTFIX

(Firefox OS Graveyard :: General, enhancement)

Description

[kskarthik]

When using phone as USB thetering or Storage device, the phone get's charged unnecessarily which decreases the battery life. So, An option should be provided in settings whether the user want to enable charging / disable charging the phone connected via USB.

Comment 1

[kskarthik]

Looks like we need to implement it by making kernel level changes.

Comment 2

[Jon Hylands [:jhylands]]

Note that its worse than that - you simply can't access the switch on most phones (its something that is available only from the baseband processor).

Note that we already have a solution for the Flame:

Turn off charging:  adb shell "echo 0 > /sys/class/power_supply/battery/charging_enabled"
Turn on charging:   adb shell "echo 1 > /sys/class/power_supply/battery/charging_enabled"

This switch, although available on the Z3C, doesn't work there.

Comment 3

[kskarthik]

(In reply to Jon Hylands [:jhylands] from comment #2)
> Note that its worse than that - you simply can't access the switch on most
> phones (its something that is available only from the baseband processor).
> 
> Note that we already have a solution for the Flame:
> 
> Turn off charging:  adb shell "echo 0 >
> /sys/class/power_supply/battery/charging_enabled"
> Turn on charging:   adb shell "echo 1 >
> /sys/class/power_supply/battery/charging_enabled"
> 
> This switch, although available on the Z3C, doesn't work there.

So what's your opinion ? Close this bug ?

Comment 4

[Jon Hylands [:jhylands]]

Dave - do you think its worthwhile for someone to investigate this again? We should probably update some of the original bugs with the findings...

Comment 5

[Dave Huseby [:huseby]]

Jon,
First of all, is charging the device bad for the battery?  Second, is it really something we should be concerned with?  Third, can't the host machine disable charging?  Like can you tell the laptop to not supply power on the USB port?

My intuition on this is that we shouldn't worry too much about this.

Comment 6

[Jon Hylands [:jhylands]]

You can't do that from the host - USB stops working if you don't provide power to the device.

I agree, though, I don't think people should worry about this with respect to battery life. Its a concern to me when I try and measure power consumption, and for some people who are working with device storage, but other than that it probably isn't worth the headache.