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    T400 9 Cell Battery

    Discussion in 'Lenovo' started by tornazer, Aug 12, 2009.

  1. tornazer

    tornazer Notebook Enthusiast

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    Is it better to take the batter out of the laptop when I have the AC plugged in? If the battery stays in (I have the stopping threshold of 90), will the AC affect the battery?

    Thanks for the inputs.
     
    tornazer, Aug 12, 2009
    #1
  2. keltix

    keltix Notebook Deity

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    Yea it's best to take it out if you are on your desktop. Although it would work as a backup power supply, you are charging and discharging the battery by leaving it in there.
     
    keltix, Aug 12, 2009
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  3. tornazer

    tornazer Notebook Enthusiast

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    I meant plugging in the AC while the battery is in.
     
    tornazer, Aug 12, 2009
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  4. keltix

    keltix Notebook Deity

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    Plugging in AC while battery is in....

    Pro: back up power supply, in case of outage
    Con: constant discharge AND charge of battery (wearing it out 2X as much)
     
    keltix, Aug 12, 2009
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  5. StealthTH

    StealthTH Notebook Evangelist

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    Setup the charging thresholds and you won't need to disconnect it. Use the Thinkpad Power Manager to do this. I have mine set to not start charging until below 35% (which is still a lot of time on the 9 cell if it sits that low) and stop charging at 95%.

    Obviously you can do what ever number you want, but I think the majority of the community would agree with the stop charging at 95%.

    With these settings you can keep your battery in the laptop, and avoid constant discharge/recharge/unnecessary cycles. Plus, if you keep the battery around 40% (like if it will be primarily plugged in all of the time) you will extend the useful life of the battery.
     
    StealthTH, Aug 12, 2009
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  6. XLiquidIceX

    XLiquidIceX Notebook Guru

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    If the battery is done charging, doesn't the power management circuit just ignore the battery and purely use AC to power the notebook?

    I don't see where these constant charge/discharge cycles come in while plugged in.
     
    XLiquidIceX, Aug 12, 2009
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  7. mbaha

    mbaha Notebook Enthusiast

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    I was thinking the same thing
     
    mbaha, Aug 12, 2009
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  8. Box801

    Box801 Notebook Geek

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    Yeah, same here.
     
    Box801, Aug 12, 2009
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  9. keltix

    keltix Notebook Deity

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    that may or may not be true, but a seller at bestbuy gave me that advice; does it apply to thinkpads??
     
    keltix, Aug 12, 2009
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  10. jonlumpkin

    jonlumpkin NBR Transmogrifier

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    The battery does become idle. However, doing intense tanks will generate a lat of heat and this is not good for batteries (especially at 100%). Additionally, the battery will lose charge over time and as soon as it hits 95% it will top off again.
     
    jonlumpkin, Aug 12, 2009
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  11. tornazer

    tornazer Notebook Enthusiast

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    I see. Is it safe to keep the battery in if I put the laptop to sleep? And I'm thinking I'll take the battery out if I plan on using it on AC for a long time. Also, I have my stopping threshold set at 90%. Is 95% a better choice?
     
    tornazer, Aug 12, 2009
    #11
  12. jonlumpkin

    jonlumpkin NBR Transmogrifier

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    It's fine, the primary concern is sustained heat at max charge. 90% (or lower) is also fine, I just wouldn't recommend over 95% for daily use (although an occasional full top off to 100% [e.g. before a plane ride] is fine).
     
    jonlumpkin, Aug 12, 2009
    #12