1. You may have noticed things look a little different around here - we've switched to a new platform (XenForo) and have some new forum styles and features. This how-to guide will help you find your way around. If you find anything that looks strange, post it in this thread.

Battery removal and CMOS battery

Discussion in 'Hardware Components and Aftermarket Upgrades' started by JOSEA, May 23, 2010.

Thread Status:
Not open for further replies.
  1. JOSEA

    JOSEA NONE

    Joined:
    Feb 6, 2010
    Messages:
    3,525
    Likes Received:
    166
    Trophy Points:
    131
    Location:
    World@WAR
    I just got an ASUS G73JH.. and have been told to charge the battery to 40% and store it out of the computer. I rarely use it on battery and power down when not in use via AC. By not leaving it plugged in, will this eventually drain my CMOS battery (as has happened on my Dell D610 (circa 2005) ?
    Thanks a lot in advance, Josea
     
  2. Fintan

    Fintan Notebook Consultant

    Joined:
    May 20, 2006
    Messages:
    138
    Likes Received:
    0
    Trophy Points:
    30
    Location:
    The Netherlands
    Yes, of course it will eventually drain the CMOS battery.

    However, this will take years.
    If you want to leave it that long on a shelf, I suggest to sell it! ;)
     
  3. moral hazard

    moral hazard Notebook Nobel Laureate

    Joined:
    Jun 17, 2009
    Messages:
    7,809
    Likes Received:
    0
    Trophy Points:
    205
    Location:
    Australia
    I suggest leaving the battery in. It's not going to wear out the battery.
     
  4. OneCool

    OneCool I AM NUMBER 67

    Joined:
    Oct 5, 2009
    Messages:
    713
    Likes Received:
    0
    Trophy Points:
    30
    Location:
    RIGHT HERE!!!
    How will the main battery drain the CMOS/Motherboard battery?
     
  5. moral hazard

    moral hazard Notebook Nobel Laureate

    Joined:
    Jun 17, 2009
    Messages:
    7,809
    Likes Received:
    0
    Trophy Points:
    205
    Location:
    Australia
    I think he means without the main battery installed, the CMOS battery wont be re-charged.

    I know with my toshiba notebooks, the CMOS battery wouldn't charge while the notebook was off (plugged into the mains but switched off).
     
  6. JOSEA

    JOSEA NONE

    Joined:
    Feb 6, 2010
    Messages:
    3,525
    Likes Received:
    166
    Trophy Points:
    131
    Location:
    World@WAR
    Exactly right that is what I mean MoralHazard (that is how it was with my Dell D610). Thanks a lot to all who have replied, I have been out of the loop for about 2 years and am trying to not ruin my new notebook. You guys are the best!:p
    I guess I will leave it in and discharge it occassionally.
     
  7. Fintan

    Fintan Notebook Consultant

    Joined:
    May 20, 2006
    Messages:
    138
    Likes Received:
    0
    Trophy Points:
    30
    Location:
    The Netherlands
    An empty CMOS battery is no great drama anyway, is it?

    Just put a new one in and you're good to go.
     
  8. ramgen

    ramgen -- Morgan Stanley --

    Joined:
    Oct 6, 2007
    Messages:
    1,322
    Likes Received:
    0
    Trophy Points:
    55
    Location:
    New York City
    Well, it may not be easily accessible. Who would like to rip his laptop entirely apart for that?


    --
     
  9. Fintan

    Fintan Notebook Consultant

    Joined:
    May 20, 2006
    Messages:
    138
    Likes Received:
    0
    Trophy Points:
    30
    Location:
    The Netherlands
    Very annoying to lose correct time on every reboot.
    Would certainly tear it apart to replace this battery (99% of cases the warranty is by then expired anyway)!
    Quite sure many are with me on this point, it isn't exactly open heart surgery.
     
  10. Trottel

    Trottel Notebook Virtuoso

    Joined:
    Jul 19, 2009
    Messages:
    2,303
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Say the bells of St. Clement's.
    Those cmos batteries aren't rechargeable. Whether you keep the battery in your laptop or not, or you keep it plugged in to ac or not isn't going to make a difference.
     
  11. moral hazard

    moral hazard Notebook Nobel Laureate

    Joined:
    Jun 17, 2009
    Messages:
    7,809
    Likes Received:
    0
    Trophy Points:
    205
    Location:
    Australia
    My Toshiba tecra A9 did charge its CMOS battery (so did my M9).
    This info was written in Toshibas documentation.

    I believe all notebooks should recharge their CMOS batteries. Otherwise how could 1 small battery keep its charge for 3+ years (I have a 10 year old notebook that never had a problem with its CMOS battery).
     
  12. Trottel

    Trottel Notebook Virtuoso

    Joined:
    Jul 19, 2009
    Messages:
    2,303
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Say the bells of St. Clement's.
    If you take out the battery, look at it, and read it, you will see that it is a non-rechargeable, 3v lithium button cell battery. Think about how often you need to replace the battery in a watch. Just because the battery is small doesn't mean it won't last a very long time under such minute loads.
     
  13. moral hazard

    moral hazard Notebook Nobel Laureate

    Joined:
    Jun 17, 2009
    Messages:
    7,809
    Likes Received:
    0
    Trophy Points:
    205
    Location:
    Australia
    When I was a kid I used those batteries for small moters and other things, I recharged them myself many times. Ripped them out of old desktops.

    Anyway, if you don't believe me, maybe you will believe the toshiba tecra a7 service manual:

    Toshiba Satellite Pro A100 / A105 - Tecra A7 Service Manual free download,schematics,datasheets,eeprom bins,pcb,repair info for test equipment and electronics

    It's a multi part download, if you have trouble downloading it, I will upload it for you on rapidshare or something (it's a 10Mb file). Just let me know.
     
  14. Trottel

    Trottel Notebook Virtuoso

    Joined:
    Jul 19, 2009
    Messages:
    2,303
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Say the bells of St. Clement's.
    Neat. I never knew NiMH CMOS batteries existed. They don't appear to be very common.
     
  15. BruBoo

    BruBoo Notebook Evangelist

    Joined:
    Mar 19, 2010
    Messages:
    486
    Likes Received:
    0
    Trophy Points:
    30
    Location:
    UK
    Agree. Every CMOS battery I have seen in ages has been a disposable lithium coin cell type, but moral hazard illustrates the need to read the service guide for your particular machine. good old Tosh ! :) My experience of rechargeable backup batteries in domestic time switches has been that they last less time than the lithium disposable ones.

    It is true that keeping the battery in the laptop will avoid the CMOS battery having to supply the CMOS. But generally it is big enough to last c 5 years doing that. The shelf life of a Lithium back up battery is 8 - 10 years but less at high temperature . .ah that would be in a a laptop then . ..

    Best assume you will replace your cmos battery in year 5. Even if soldered in it is not too hard a job - your local TV repair shop can do it quicker and cheaper than a laptop specialist if you have opened it up for them.

    The main battery will also die in 5 - 6 years even stored at 40% outside the laptop. Stored at 100% inside the laptop 3 years is more like it before significant capacity loss. Main batteries also have a cycle life so if you use it as a 'laptop' a few days a week it will last less time.

    Better approach is to assume a 3 - 4 year old laptop is about to start needing expensive replacement HDD's, Batteries, adapters, Fans, CMOS batteries etc and that if you bought all of those one day you could probably spend half the cost of a new, guaranteed 2013 model netbook with the same (now totally obsolete) spec. So be glad it lasted that long and save up for the new one :)
     
  16. woofer00

    woofer00 Wanderer

    Joined:
    Mar 4, 2010
    Messages:
    1,086
    Likes Received:
    0
    Trophy Points:
    55
    Location:
    New York
    I was under the impression that CMOS batteries didn't discharge unless no other power source was plugged in - so for desktops, if the power is disconnected; for laptops, if both AC plug and main battery are out. I've got had computers that survived well over 8 years without ever changing the CMOS battery, as well as CMOS batteries that came to me dead from the manufacturer. Oddly enough, 2 of the 8 or 9 desktop motherboards I've purchased over the years arrived with the CMOS battery flipped over.
     
Thread Status:
Not open for further replies.

Share This Page