touch-packages team mailing list archive

[Matthew Exon <mat.ubuntu@xxxxxxxxx>]

@pat-mcgowan:

"The battery then decides that charging is over and automatically
switches off."

This model of battery pack tries to figure out when the plugged-in
device has got to 100% charge, and when it detects that situation it
switches itself off and stops supplying power.  It then won't supply any
more current until I switch it back on by pressing a button on the
front.  Presumably the idea is to save power by switching off both the
battery pack's and the device's charging circuits.

In this case I have a phone at 60% charge and I want to top it up.  I
plug it into the battery and it starts drawing current.  Then I go to
sleep.  After a couple of hours the phone is at 100% and it stops
drawing current from the USB battery.  The battery detects this drop in
current and switches itself off.  But the phone's screen stays on.
After a while it would like to top itself up again, but the battery is
switched off and won't supply current until I press the button.  So the
phone just keeps draining itself until I wake up, by which time it's
back to 60%.

This is a fairly normal USB power bank, brand name Anker (but likely a
fake).  I'm pretty sure I've seen this behaviour in other battery packs.

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https://bugs.launchpad.net/bugs/1512211

Title:
  Charging from USB battery, phone stops charging, switches on screen,
  and discharges

Status in Canonical System Image:
  Incomplete
Status in Ubuntu UX:
  Fix Committed
Status in Unity System Compositor:
  New
Status in unity-system-compositor package in Ubuntu:
  New

Bug description:
  When I was travelling recently I found that if I plugged into a USB
  battery overnight to charge my phone, when I got up the next morning
  the phone didn't have any more power than when I started.

  Turns out the reason is: when the phone decides the battery is full,
  it stops drawing current.  The battery then decides that charging is
  over and automatically switches off.  The phone then decides that it's
  been unplugged and turns the screen on.  I had set the phone to not
  automatically switch the screen off, so it just left the screen on all
  night.  The next morning it was as if it had never charged.

  So I have the following suggestions:

  1) Just don't turn the screen on when the user unplugs the charger
  2) If the intention is to let the user know that the charger has been unplugged, pop up a message.  Just turning the screen on isn't very useful feedback.
  3) If you are turning the screen on automatically it "doesn't count" wrt the user's "automatically turn off screen after..." setting.  This should always be just a few seconds.
  4) If the user has configured the phone to not automatically switch off the screen, don't automatically turn it on either
  5) Give me a few more options for automatically switching off the screen - 1, 2, 3, 4, 5 and 10 is a lot of resolution at the low end.  Where is 30mins and 1hour?

  P.S. this has nothing to do with webbrowser-app but I still can't
  figure out how to search launchpad for Ubuntu touch packages.

  
  ===============UX comment===================
  I will try to address all the points raised in the bug description.

  1) is invalid, we should turn on the screen when the user unplugs
  the charger and possibly show a message reminding the user to unplug
  the charger from the wall socket (if any).

  I agree with 2), the system should show a system message as well. This is already specified as one of the usecases of the new notifications system UX (which hasn't been implemented yet). 
  https://docs.google.com/document/d/1xDSZ_dnAMAlhgFnnyjJEibaITXjVLp1_pnj_tATNm9I (private link)

  I agree with 3) and this behaviour is already specified in the Screen blanking policy, that means it is on the plan to implement it (if it's not already)
  https://docs.google.com/document/d/1RBoVknCLZ4GQ8E_iVftd3i_KmdxI5d6JrBt7i5EDZO0 (private link)

  4) is taken care of by implementing 3)

  Point 5) is valid but requires a new bug which should also specify the usecases when those longer values would be needed, so that UX designers can better understand the needs and the reasons behind a UX suggestion :)
  Matthew, could you please file that bug? :)

  Point 6) (the one presented in comment #1) is valid but requires a new bug, mentioning the usecases, just like 5). I have to say I am not really into that feature, because the screen backlight of devices like the Meizu MX4 probably consumes more power than a USB port provides (which is usually 500mA). So it needs special care and convincing usecases :)
  Matthew, could you please file that bug, specifying some usecases when this feature would be really handy? :) I can't promise we will implement it, but we can discuss it ;)

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