Page 1 of 2 12 LastLast
Results 1 to 10 of 11
  1. #1
    morgenmuffel
    Join Date
    Dec 2004
    Location
    Putaruru
    Posts
    2,905

    Default laptop batteries holding charge

    toshiba M30 laptop
    purchased january 2005

    Do laptop batteries normally lose their charge completely (from being fully charged) if left sitting, not being used

    also in the space of one week it went fom being fully charged to 25% charged without being used

    Thanks in advance
    Morgenmuffel - This word needs to be a part of the english language, in fact you should use it in everyday conversation

  2. #2
    6146-B Billy T's Avatar
    Join Date
    Dec 2004
    Location
    Middle Earth
    Posts
    6,887

    Default Re: laptop batteries holding charge

    Yes

    Lithium-ion batterries have quite a high self-discharge rate, and nicads are not far behind. In addition, the older lithium-ion batteries get, the faster they lose their charge.

    In my experience (and usage patterns) they are no better than nicads in many respects.

    Google will tell you more.

    Cheers

    Billy 8-{)
    Some days it's not even worth chewing through my restraints!

  3. #3
    Pedant and proud of it
    Join Date
    Dec 2004
    Location
    Christchurch
    Posts
    6,047

    Default Re: laptop batteries holding charge

    A lithium-ion should hold its charge quite well. It's an "advanced technology". I have one I bought from DSE for $5 because they hadn't sold it for too, too, long, so it had been a couple of years without being charged. It's at over 90%.

    I'd say you should get a replacement of one you've had for three months.

    If I had 3 month old NiXXs which lost 75% of charge in a week of no use I'd be back for replacements too.

  4. #4
    Senior Member godfather's Avatar
    Join Date
    Dec 2004
    Location
    Central New Munster
    Posts
    3,053

    Default Re: laptop batteries holding charge

    Quote Originally Posted by Nigel
    toshiba M30 laptop
    purchased january 2005

    Do laptop batteries normally lose their charge completely (from being fully charged) if left sitting, not being used

    also in the space of one week it went fom being fully charged to 25% charged without being used

    Thanks in advance
    Just make sure that you are "shutting down" fully, and not just going to "standby" though, or internal computer draw will run the battery down.

  5. #5
    6146-B Billy T's Avatar
    Join Date
    Dec 2004
    Location
    Middle Earth
    Posts
    6,887

    Default Re: laptop batteries holding charge

    They are ok when new and out of the computer Graham, but if left in the computer they run down quite quickly. Their in-built protection circuit also adds to the discharge rate. Keeping them cool helps as the discharge rate rises sharply with temperature.

    Taking all factors into consideration they can go down at 10%/24hrs, which fits with 25% after 1 week so Nigel's experience is not extraordinary, however he could have a bad battery, and the power meter might not be all that accurate either.

    Cheers

    Billy 8-{)
    Some days it's not even worth chewing through my restraints!

  6. #6
    Pedant and proud of it
    Join Date
    Dec 2004
    Location
    Christchurch
    Posts
    6,047

    Default Re: laptop batteries holding charge

    The protection circuits (marvelous chips ... I've had a look at the data sheets, and have a few applications in mind) use microamps (or less). And they are in the battery all the time. 10% in 24 hours would be a continuous drain of over 12 mA (for a 3AH battery).

    GF's suggestion that the computer might be running seems more plausible, but what is it doing? That sort of drain is too low.

  7. #7
    6146-B Billy T's Avatar
    Join Date
    Dec 2004
    Location
    Middle Earth
    Posts
    6,887

    Default Re: laptop batteries holding charge

    Quote Originally Posted by Graham L
    The protection circuits (marvelous chips ... I've had a look at the data sheets, and have a few applications in mind) use microamps (or less). And they are in the battery all the time. 10% in 24 hours would be a continuous drain of over 12 mA (for a 3AH battery).
    Yes, I know it doesn't sound likely, but some lithium battery pack makers quote 5%/24hrs natural discharge plus 3%/24hrs for the protection circuit. Part of that protection is cell voltage balancing and that implies parallel resistance. Add any fixed drain that the laptop may take even when switched off, plus very warm temperatures after use and it is not hard to see where the capacity can go. Keeping the battery in a plastic bag in the fridge between uses will make a big difference.

    My Toshiba Portege has a similar discharge rate and that is with a brand-new OEM high capacity battery.

    Cheers

    Billy 8-{)
    Some days it's not even worth chewing through my restraints!

  8. #8
    Pedant and proud of it
    Join Date
    Dec 2004
    Location
    Christchurch
    Posts
    6,047

    Default Re: laptop batteries holding charge

    So the manufacturers can't sell them, Billy? After manufacture, they are unlikely to be sold in less than a month or so. If Li-Ion cells drop below a critical point, they are unrecoverable. The protection circuits won't allow them to be charged.

  9. #9
    Senior Member Strommer's Avatar
    Join Date
    Dec 2004
    Location
    Masterton
    Posts
    3,869

    Default Re: laptop batteries holding charge

    Quote Originally Posted by Graham L
    If Li-Ion cells drop below a critical point, they are unrecoverable. The protection circuits won't allow them to be charged.
    So we need to keep batteries in laptops and charge them (use the laptop) regularly, say weekly? I recall a similar thread on this topic last year, which said that laptop batteries should be taken out (assuming the laptop is normally used with a power cord) to ensure a long battery life.

    What is correct?
    .
    .

    The whole problem with the world is that fools and fanatics
    are always so certain of themselves, but wiser people so full of doubts.

    ~ Bertrand Russell

  10. #10
    6146-B Billy T's Avatar
    Join Date
    Dec 2004
    Location
    Middle Earth
    Posts
    6,887

    Default Re: laptop batteries holding charge

    Quote Originally Posted by Graham L
    So the manufacturers can't sell them, Billy? After manufacture, they are unlikely to be sold in less than a month or so. If Li-Ion cells drop below a critical point, they are unrecoverable. The protection circuits won't allow them to be charged.
    I don't know the answer to that one Graham, but I do know how fast my new batteries self-discharge. Dont forget though that the self discharge will taper off as the voltage reduces and what is too low to run a computer is not necessarily all that close to the critical "non-recovery" point.

    That critical point is not actually non-recoverable either and there is technology out there that can recover from shutdown. Take a look at This Link

    Cheers

    Billy 8-{)
    Some days it's not even worth chewing through my restraints!

Similar Threads

  1. Varta 15 Min Charge & Go Batteries.
    By bob_doe_nz in forum PC World Chat
    Replies: 10
    Last Post: 21-10-2008, 08:11 PM
  2. Replies: 6
    Last Post: 24-06-2006, 10:00 PM
  3. Laptop batteries- How to extend overall life?
    By Sick Puppy in forum PressF1
    Replies: 4
    Last Post: 18-06-2006, 12:43 AM
  4. Compaq Presario LapTop won't charge battery
    By doccock in forum PressF1
    Replies: 5
    Last Post: 05-05-2003, 04:25 PM
  5. pre loved laptop batteries
    By Hugh Jarse in forum PressF1
    Replies: 3
    Last Post: 05-04-2003, 07:35 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •