Toshiba AC100 – Hardware Fault? – (Battery Life)

Posted on 30 August 2010, Last updated on 10 June 2018 by

For the last two nights I’ve been testing the ‘standby’ battery life on the Toshiba AC100. [Unboxing and overview video here] On the first test the battery was at about 30% capacity. I closed the lid and expected to have plenty of battery life left in the morning. When I woke up, the AC100 was dead. On the second test the battery was again at 30%. This time I turned the WiFi off before closing the lid. In that scenario I’d expect next to no drain at all. Again, when I woke up 7 hours later, the device was dead. Something’s wrong.

Looking at the battery information I’m seeing something strange.


Can you spot the issue on my WiFi-only AC100?

Yup, somehow the 3G subsystem is draining power which is really quite strange considering I don’t have 3G on this device. Have they left the 3G radio on the device and just removed the SIM slot? Have they forgotten to turn the 3G off in the firmware? Does ‘cell standby’ actually mean something else? I can’t imagine another subsystem in the AC100 that would take more power than the screen and Wifi. On my Android phone here, cell standby is taking only 9% of the power. When the firmware contains strings like ‘eng/test-keys’, commonly found on test builds, you’ve got to wonder what’s going on.

I’ll have to raise a support issue on this with Toshiba Europe.

Note: 12mins later, the graph was still the same. Cell Standby is taking 77% of the battery drain. Going to ‘airplane mode’ doesn’t appear to help.

Note: 30 mins later and ‘cell standby’ is up to 81%.

Anyone else experiencing the same on their AC100 (Is there anyone else out there with an AC100?)

Update: Just to be clear – active battery life is around the 6hrs mark (50% screen, wifi on) so there’s no problem with that. I’ve also found a lot of threads on forums that question the ‘cell standby’ measurement. One response says it’s a known issue in Android 2.1. Currently manually measuring screen-off drain.

In a third test last night I went to bed with about 60% drain. I woke up with 20% left – and the screen on. Something is turning the screen on and causing the drain. Have now done a factory reset to remove any of my sideloaded apps that may be turning the screen on. I’ll do another overnight test tonight.

Update: 1535 –  31 August.

With a fresh factory reset I’ve been testing the battery life over the last few hours.

With screen off, wifi on, idle, no usb subsystem, no sdcard i’m seeing 6 mins per 1% battery drain. That’s really not that good. – 2.4W average drain. I’m expecting more like 1W.

With screen off, AIRPLANE MODE, no USB subsystem, no sdcard, idle, I’m seeing 13 mins per 1% battery drain. That’s 1.14W drain which is terrible for an ARM system. A smartphone with screen off and airplane mode would take about 20-50mw. Remember, the AC100 is effectively has smartphone internals so when you turn the screen off, there should be no difference (i’ve turned the USB host subsystem off and removed the SDcard to remove that from the equation.)  Something is sapping over 90% of the battery – which brings us back to the cell subsystem which, after these tests, was taking 84% of the power according to ‘battery status’ under Android.  At this stage, i’m tempted to pull it apart. Will I find a surprise 3G module inside?

Update2 – 31st August.

I won’t be doing any more review work on the AC100 until I get to the bottom of this power issue because it’s a huge problem that takes away the main reason to have it in the first place. ARM-based devices do a good job at ‘always on’. Take the Archos 5 for example. It’s a Cortex-based Android device and just 30 minutes ago I checked some stats on it. It’s been sitting on my desk in a screen-off, wifi-off state for 4 days and 8 hours and get this, it has a battery that’s less than half the size of the battery in the AC100. Not only that, there’s 45% of the battery left. That’s under 50mw of drain. 20x less than the AC100. There’s the problem with the AC100!

Update 3: 5th Sept.

Toshiba Germany tell us that Froyo will be delivered in 6 weeks (Mid October) for the AC100. We have also reported the details of the above issue directly to the German product manager.

P.S. Don’t forget to check out my Toshiba AC100 unboxing and overview video. (embeded below)

30 Comments For This Post

  1. Brad Linder says:

    I’ve noticed the same thing on some cheap Android tablets. It seems like the only way to avoid this is to perform a complete shutdown instead of putting the device into standby mode. Not a good solution, since it takes about as long to cold boot an Android device as a Windows computer — which kind of makes me wonder why you’d bother getting one over the other.

  2. says:

    Could it be that it’s difficult to disable (rip out?) the 3G controller stuff? And that leaving it in means it will eternally probe for non-existent hardware to fire up?

  3. Travis says:

    Why 7 tweets about hardware failure all the same most have links to 404?

  4. chippy says:

    Sorry. My fault as Livewriter kept reporting an error (when it had in fact posted correctly!)

  5. John Q. Public says:

    I noticed the same thing on an Augen tablet that I owned for a couple weeks. The solution, although not ideal, was to remove Phone.apk and TelephonyProvider.apk from the device. This prevented Cell Standby from hogging all the battery but had the unfortunate effect of making the YouTube application unusable.

  6. lhl says:

    Looks like my other comment got caught up in moderation (it had a link to how people solved this similar to what John Q posted), but you can also ‘adb logcat’ to see what’s making the calls if you have USB debugging on in the system preferences and the Android SDK that you can plug it into.

  7. chippy says:

    Can’t see any comments waiting for moderation. Try the link again.

    Currently with wifi on and screen OFF, the AC100 is taking about 6 mins per %. Thats 10hrs total – not good for screen off, wifi on with a 24wh battery. It should be 5x that amount.

  8. Friedrich says:

    Hi Chippy,

    as I already said I have got the exact same problems. The AC100 woke up, sceen was on, battery empty.
    Cell standby is always about 78% in my case. Very strange! I have got the model without 3G.

    There is aggressive marketing that the AC100 has lots of battery life.

    here: Always On –


    Do you know a little bit more about the problem by now?
    Can it be solved by a software update?

    If not, I intend to send it back.

    Thanks for any new insights.

  9. chippy says:

    I’m meeting and speaking to Toshiba this week. I think it’s a firmware problem If not, they will need to recall these. They are useless!

  10. pispot says:

    that’s horrible.
    even my X200 thinkpad tablet with core2duo goes below 3.5 Watt/h with wlan on and screen off.

    always on should be THE key feature of a smartbook.

  11. Friedrich says:

    I have got the same problems. Battery drain is too extensive. And I had the same problem that the AC100 had been woken up and battery was empty.
    In my case I guess the culprit was “snowstorm” an weather widget.

    Do you see a possiblity that this can be changed?


  12. chippy says:

    Approved your previous comment. Sorry, it was held due to links.

  13. Friedrich says:

    Chippy, thanks!
    I would be really grateful if you could keep me/us informed. I have to decide whether to send it back in time for warranty or if I keep it.

    Your verdict is clear. And yes, you are probably right.
    I have sent an email to Toshiba. Will keep you informed as soon as I get an answer, if I get an answer.
    Thanks again!

    PS A while ago you helped me with the HTC’s shift. Always grateful.

  14. Guest says:

    Do external 3G USB modems work generally on Toshiba AC100? Not the integrated one.

    If someone would be able to test.

  15. Friedrich says:

    Hi chippy,
    could you speak with Toshiba about the battery problems of the AC100? I know you are drowning in tablets at the IFA, but an answer what Toshiba intends to do would be appreciated. I sent them a mail, but no answer so far.
    Thanks for the blogs form IFA.


  16. Friedrich says:

    Hi chippy,
    in a tweet you just said that the AC100 will get Froyo in 6 weeks. Did you ask about the poor battery performance of the AC100? And did they comment it?
    I have got Froyo on my Nexus. Is there a chance that the battery life will improve?


  17. w0nk0 says:

    I have the same issue with a Dell Streak (5″ smartphone/tablet) running Android 2.1. Cell Standby uses as much power as the display, which is WAY too high. After researching this for 2 days on the web, it seems many people have this issue with all kinds of Android phones.

    I’m beginning to suspect that something in the recent(?) kernels is wrong regarding cell radio management. I’ll try to look at dmesg and other debug kernel output and will conduct more studies on it..

    Please keep us posted on your findings!

  18. PaulR says:

    I have exactly the same problem.

  19. PaulR says:

    I have the same problem ie battery drains overnight.
    Have returned unit to retailer for checking, but there is nothing they can do.
    The 3G slot is sealed up, but probably has a live wire or a short circuit behind the seal.

  20. Chippy says:

    I will be speaking to Toshiba this week about battery issues and 2.2

  21. I4U says:

    I’m encountering exactly the same problem with the AC100-114 (without 3G). I hope a quick fix! I remark that, even sleeping, the bottom center is noticeably hot. Probably the cortex running quite hard.

  22. Sovereign says:

    I’ve been experiencing the exactly same problem.
    It’s pretty absurd that I can barely keep an android device with the 24wh battery turned on for a day.
    As a so-called early adopter, I’ve bought 52 computers and smartphones. Among these are iPhone 4, Galaxy S and AC100 which has been the worst gadget ever.
    As soon as I turned on the device, I encountered lots of problems, to say, the omission of Market, incapability of language toggle (you know, I am a Korean user who bought one of the 50 limited Korean version of AC100. There are language toggle keys, two alt keys and two ctrl keys that are not functioning at all, how foolish), this battery problem and so on.
    I purchased this AC100 here in Korea with almost $500 which can manage to buy many well-finished netbooks.
    I don’t believe Toshiba can release this clummy device.

  23. Andy Garton says:

    FWIW I fixed this problem on my UK 3G model by turning NewsRob synchronization off.

  24. Danny says:

    >>When I woke up, the AC100 was dead. On the second test the battery was >>again at 30%. This time I turned the WiFi off before closing the lid. >>In that scenario I’d expect next to no drain at all. Again, when I >>woke up 7 hours later, the device was dead. Something’s wrong.

    HI..Chippy, there’s one recommendation for improving BATT life.
    Maybe you can try on setting to disable screen time out function for solving battery unexpected drain issue, because screen time out function
    would let system first to idle mode when time out(display off but system on) and drain 1.14W from BATT and not into sleep mode( display off and system off), so when you disable screen time out function in setting, yor system could enter sleep mode smoothly when lid close!

  25. Mzungu says:

    I somehow assume that these problems result from a lousy Android implementation.

    My suspended AC100 also reconnects to UMTS and thus remains hot. Further meanwhile the thing is “Unable to start Wi-Fi”

    We need Ubuntu running!

  26. Friedrich says:

    Let’s face it. The AC 100 is a play thing. It was a rather disappointing experience, but it is over. I am auctioning it and I have already climbed the ladder of gadgetry and I must say Apple’s Air 11″ is the solution for me.
    What a beautiful piece of design and functionality! Just to look at it makes me smile with pleasure.
    I run it in standby mode so it is immediately ready for work. And in standby mode it doesn’t lose any or very little power. I am thrilled!

  27. Sovereign says:

    I’ve also become a user of Air 11″ and I agree with you on every word of your comment.
    I’m afraid I cannot auction AC100 because nobody around me understands the concept of so-called Smart Book and they’d definitely be mad when they come to find out that this laptop-like thing cannot run neither windows games nor itunes apps.

  28. chippy says:

    How do you guys feel about always-on and the app store. Something you are missing from the mba? What about the cost difference? Dual-core networks weren’t in your shortlist? I’m always interested in feedback from you users so if you have time i would love to hear more.

  29. Friedrich says:

    Hi chippy,
    of course, there is a considerable price difference, but as I said before, you can really work with the Air 11″. It has is not considerably heavier than the AC100, it is completely silent, you can use it immediately using standby. Even booting it up is done in 15-20 seconds. It is fast. And you do not have to fiddle like one has to with the AC100. And the finish, whoopee!
    As I recently changed from the Nexus to the Galaxy Tab I can use the app store, but I am not sure what you mean by app store.
    And I also have the iPad. So I can also use their app store.

  30. e3k says:

    any news about the battery issue? i was about to buy this but now i am unsure… is it a hw or sw issue? if sw only i am going to put my own os on this thing:

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