Stream Tablets Standby Battery Drain Workaround

[darrenc]

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@jeffmdaemon wrote:

So after doing some testing the past several hours I have come to this conclusion about UART,

When using connected standby;

1) UART rains battery at a huge rate when BT/Wifi is enabled. 

2) UART drains at a huge rate when BT is turned off and wifi is left on. 

3) Nothing happens when airplane mode is activated, sleepstudy showes everything at %0 and the battery didnt drop at all over 2 hours. 

So if i had to point fingers at anything, it is a wifi issue. I tried uninstalling the bluetooth radio and letting it reinstall too (because past UART issues were a bluetooth bug when it was OFF) but it changed nothing.

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But that is likely a manifestation of your router not supporting low-power mode.  As you can see in my sleep study, my wifi is active (as is my bluetooth) but my wifi is in-fact dropping to low-power mode and its battery drain is then minimal.

[jeffmdaemon]

Lack of LPM on my router does not cause devices to drain the battery. -_- Low power modes is a nice perk, but much like bluetooth pre-4.0, the chips we use in todays portables are pretty low powered allready. 

[darrenc]

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@jeffmdaemon wrote:

Lack of LPM on my router does not cause devices to drain the battery. -_-

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How do you figure that?

As long as your device's wifi adapter is connected to a router that will not support LPM, your device must keep the wifi adapter in high-performance mode.  High performance mode of your device's wifi adapter uses SIGNIFICANTLY more power.

[jeffmdaemon]

Because none of my other portable devices like my phones are doing the same. Nore if you search google, not once is the lack of LPM mode on the router blamed for killing batteries. There is a small amont of power savings, but it is not the difference between a mear sippage of %3 battery life in 12 hours, and losing %80 of your battery when you wake up the next morning. 

[darrenc]

You said yourself that if you turn the wifi off, the power drain stops.  As far as we know so far, the only difference between yours and mine is that mine drops to LPM and yours doesn't.  Chances are pretty good that any of your other low-battery-capacity portable devices don't even have an energy-sucking high performance wifi mode.  Your Stream is running a full Windows OS that will use lots of power unless it's forced not to.

As far as finding anything on google about it, what's really comparible that's been around long enough?  Once there are more tiny tablets with tiny batteries running full versions of Windows, you'll start to see lots of things about what does and doesn't use too much of that tiny battery.

[jeffmdaemon]

I am suspecting a driver issue.. something clearly isn't behaving. UART doe not stay active %100 of the time because of LPM, it does it because something is wrong. I am trying to figure out if I installed anything new driver wise, there does not seem to be a rollback option available so I think not. At the same time windows wants me to install a lan usb2 for high speed ethernet driver which is off cause there is no ethernet. ^^ 

[teeth_03]

Here is a thought, why don't you delete the wireless profile for your router so it disconnects but leave WiFi still turned on?

[stream63]

I have found the best solution to the battery drain is to shut down my stream when not in use. It boots up fast enough on start up.

[brachiopod]

Yeah, I set mine to shut down. It uses "fast boot" which is sort of a hybrid between booting and hibernation where the OS is placed in a hibernation file. I think that maybe the best solution for now would be to set the tablet to hibernate, although that would use 1GB of disk space. Unfortunately they have removed the hibernate option in the power settings, even if you go in and try to "edit unavailable options". There may be a way to restore the hibernation option by using the "group policy editor" on the tablet, but that is not installed either and it is quite a procedure to get that installed so I have not tried yet.

[darrenc]

Jeff, are you still having this UART issue?

I noticed yesterday that my sleep power drain had jacked way back up again (even worse than with the volume issue).  When checking into it, guess what was doing it?  Yep, UART.  After messing with it for quite a while, I finally figured out that my drive sharing was the problem.  I had recently set up an advanced share on my MicroUSB card so I could transfer music files from my laptop straight to the Stream using wifi lan.  Previously, I had simply used a USB thumb drive to move bulk files and went the other way over the network (used the Stream to pull them rather than the laptop to push them) for isolated files.

Once I disabled the share, the UART has disappeared back out of my 'no sleep' requests and my power drain is back to minimal.

Just an idea, maybe worth checking to see if something like that is what's hitting yours so hard.