1. CafeChemist's Avatar
    I've had my Surface 2 since soon after launch. I had been pretty happy with it, especially with the standby battery life. However, around November 22nd, my battery life plummeted. Instead of charging every 5 days or so, I had to charge daily or every other day. I did some searching using cmd powercfg and I think the problem has been narrowed down. It looks like Microsoft's drivers for the Surface 2 are preventing the Surface 2 from entering the correct sleep state during connected standby, along with a Tegra driver that is also problematic. The worst thing is that the Microsoft driver issue (Microsoft UART V2 Driver) has been known since Window 8.1 Preview, and apparently the November updates unfixed it. The workaround for this is to turn on the bluetooth radio to reduce the battery consumption (counter-intuitive, right?). Unfortunately, when I went to turn on my Bluetooth, the menu option was missing (?!). Further investigation in the device manager revealed that the hardware was not recognizing the Bluetooth radio. So apparently the November updates that fixed some issues caused a lot of collateral damage. Evidence below:

    Used cmd powercfg -battery report to check battery drain patterns. Connected standby battery life plummets after Nov. 22nd (also the first day when my sound drivers started acting up):

    So I used cmd powercfg /sleepstudy to see what was going on during connected standby. Results show that during connected standby, the computer is being kept active, rather than using the proper sleep state:

    Looking at the processes that were active, two drivers seem to be causing the issues: Microsoft UART V2 Driver and Tegra I2C Controller Driver:

    Did some web searches for offending drivers. While not much info about the Tegra driver, the Microsoft driver had many discussions. Apparently, UART V2 is somehow connected to the Bluetooth ratio state. There is a known bug in the Windows RT 8.1 Preview that was causing high battery drain when the Bluetooth radio was off. Turning the Bluetooth radio on resolved the issue:

    More info, with Microsoft acknowledging issue in Preview build:

    It's a shame that an issue known in Preview wasn't fixed for general release, or was unfixed by the November update, but that seems to be the case. I decided to check my Bluetooth radio to see if turning it on would help. However, the PC and devices menu somehow lost the Bluetooth menu (should be between Display and Devices):

    Web search reported that changes in desktop Bluetooth settings could remove menu option in modern settings... Going into the device manager to look for the Bluetooth settings, it turned out that Bluetooth was greyed out:

    Checking the properties of the Bluetooth controller, is seems that my Surface 2 no longer has Bluetooth:

    My next steps are to try refreshing my Surface 2 to see whether my Bluetooth will come back, and whether that will fix my connected standby power drains. Altogether, it is absolutely ridiculous that I'm having to go through this, just to have a product that functions as it is marketed. If Microsoft wants to sell products to general audiences, they cannot have software/hardware(?) issues that require so much poking around to fix. The apparent mantra of "Check for updates/refresh your Surface" by tech support really is not acceptable, when issues acknowledged more than four months ago are the underlying problems. Will post my observations after refreshing.
    11-28-2013 03:09 PM
  2. malberti1993's Avatar
    I had set my mail to push hourly and it made my standby battery drain a lot less.
    11-28-2013 04:47 PM
  3. cbreze's Avatar
    That explains why my Bluetooth would never connect, paired but no connection. One just has to wonder and shake their heads regarding some of these "updates" that actually do more harm than good. Thanks for the post OP.
    11-28-2013 05:52 PM
  4. realwarder's Avatar
    I have to say that the Surface Engineering Team are pretty poor. An example is with the original Surface RT... they took months to fix the Wi-Fi driver, and I mean 12 months. And then at one point the sound driver was updated to 'make things louder'. The trouble was it introduced a bug which meant that when the volume was quiet it faded the sound in and out. Seriously! Didn't anyone bother to test a quiet volume?

    Other things were wrong with the keyboards not always working and Windows button not always waking the unit...

    And they only had ONE tablet to test and get solid. It's like they had their interns testing and fixing it.

    * rant over *

    I like the hardware, just very very disappointed in their platform support from a software/firmware perspective.
    11-30-2013 09:31 PM
  5. livekyle's Avatar
    @OP: have you managed to resolve the issue?

    When I went to bed last night my Surface had 26% left. This morning I was surprised to see that it had turned off over night and that it displayed the low battery sign when I hit the power button. powercfg /batteryreport revealed that it had been active for over 2 hrs from the point where I went to bed (screen obviously turned off). It lost 22% during that period and then turned itself off. powercfg /sleepstudy is problematic for me. It only worked once when I tried it like two weeks ago. I tried it several times since then (and also today, obsiously) but all it says is that an error occured and it can't generate the report (yes, I run cmd as admin!).
    So I can't be sure what caused the drain but I guess it was the same problem that you had (or at least a similar one...).

    Do we have to live with this sluggish software forever or will they fix this at any point? Any infos on that?
    12-21-2013 07:42 AM
  6. cbreze's Avatar
    I notice if I leave my USB mouse plugged in when I'm not using it, it drains battery pretty fast. I need to unplug it when I leave for the day or else turn off the surface. I always turn it off at night anyway. I really like how it re-charges quickly tho. Full charge in about 90 minutes where my iPad takes at least 6 or 7 hours to do the same.
    12-21-2013 11:08 AM
  7. Warpc0re's Avatar
    i ran a test myself.
    So I charged my surface 2 and then started the timer.
    With the WiFi on, and not using the Surface at all for anything (sleep mode) it was draining 1% every 30 minutes. It dropped to 92 % in just about 6 hours.
    With the WiFi off, and not using the Surface at all for anything (sleep mode) it went from 100% to 99% in about 3 1/2 hours.

    definitely something going on with the surface set to have the wifi on.
    MDak280 likes this.
    12-26-2013 10:08 AM
  8. cbreze's Avatar
    If I'm going to be away from it more than 30 minutes I'll just turn it off. Zero battery drain and it boots back up in 22 sec, sign in 3 sec, for a total 25 sec for zero battery drain. My iPad doesn't boot up that quick. Anyway, problem solved IMO.
    12-26-2013 10:34 AM
  9. Warpc0re's Avatar
    I agree w/Cbreze, basically you can do that., however, I just did this to test out and see if indeed the wifi was eating up the battery. Granted, my Ipad, when its in sleep mode, no issues there.... I can charge it fully and 8 hours later, the reading is still 100% without having to turn it off. Maybe it might not be a fair comparison because they are built different and use different OS. Maybe , I have been to spoiled with the Ipad battery life :)
    12-26-2013 02:32 PM
  10. photobriangray's Avatar
    Connected standby does take a bit more power than the simple push info of other tablets, it seems. I will give up a bit battery life to have all my updates staring me in the face when I pick up the tablet.
    12-28-2013 11:47 AM

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