Prolonging laptop battery life

Discussion in 'General Electronics Chat' started by Alec_t, Jan 24, 2016.

  1. Alec_t

    Thread Starter AAC Fanatic!

    Sep 17, 2013
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    My newish Lenovo laptop had the decency to pop up a message recently to remind me that running the laptop most of the time off the mains adapter (i.e keeping it at full charge) wasn't good for the battery and would shorten its life. However, bearing in mind that battery life is also dependent on the number of charge/discharge cycles, it is clear that running mainly from battery is also not good for battery life. From what I recall, lithium batteries are best kept at around 70%(?) of full charge. So, what is the Forum's view on the best way to maximise battery life?
     
  2. cmartinez

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    Jan 17, 2007
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    Interesting question... there's a website named Battery University, that I'm sure has the answer to that.

    I do remember that, when it comes to lithium batteries, what really does damage them is when they get discharged below 22%. But I've never heard before that keeping them fully charged affects them negatively.
     
  3. GetDeviceInfo

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    Jun 7, 2009
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    I see different things from different sites, but, if you consider that a fully charged battery is under higher voltage potential, or stress. A lithium delivering the bulk of its power in the 3.7 to 3.3 range, has less capacity at the higher 4.2 range, but is under increased stress. My vote is to cycle it through its nominal voltage range, avoiding the extremes.

    That just speaks to the battery, it doesn't address the long term strategy of cycling the battery as opposed to running on AC. Id say that your battery will last much longer if you don't use it, compared to cycling.
     
    Last edited: Jan 25, 2016
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  4. recklessrog

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    May 23, 2013
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    My Samsung laptop has an option for when it is primarily used on mains power to reduce the battery charge to 80%. This, they say, is to prolong battery life.
     
  5. crutschow

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    Mar 14, 2008
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    Yes, I've also heard that keeping a Li-ion battery continuously on the charger is not good for its life.

    I run my laptop on mains most of the time but occasionally run the battery down to about 2/3rds capacity, to sort of de-stress it (not sure if that really helps, though).

    I also never leave it on charge when I'm not using it, unless I'm trying to charge it for some portable use without the charger.

    Perhaps it would help some to run the laptop on the battery for a few minutes before you shut down so the battery is not totally fully charged when idle.
     
  6. Alec_t

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    Thanks for the replies, guys.
    That's what I tend to do. But then the next time I use mains power the battery goes back to full charge, of course. Does this partial charge cycle count against longevity as much as a full charge cycle would? I guess not, but it's only a guess.
     
  7. hp1729

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    Nov 23, 2015
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    Yes, batteries have a finite life no matter what you do.
    Just don't let them discharge down too far. That really shortens their life.
     
  8. wayneh

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    Sep 9, 2010
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    Ditto.
     
  9. MrSoftware

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    Oct 29, 2013
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    Different battery chemistries have different characteristics. Lead acid batteries last longest if they're kept at full charge. Lithium Ion batteries last longest if kept somewhere in the middle. IMHO, just use it and replace the battery when necessary. If battery expense is a real concern for you, then run the battery down to around 50%, hibernate the OS and remove the battery before plugging into mains. Now you can just resume. When it's time to travel, hibernate, insert the battery and charge it up.
     
  10. Alec_t

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    Interesting suggestion, but is that safe? I would be concerned that the battery could be part of the supply voltage regulation/stabilisation arrangement within the laptop. Also, it could perhaps provide high instantaneous current to meet short-term peak demands, which the mains brick might not be able to. Are those concerns unfounded? This is the sort of info which isn't in the typical laptop user manual :(.
     
  11. MrSoftware

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    We've run plenty of laptops sans-battery around here, never had a problem. Unless someone unplugged it while it was on. ;)
     
  12. Alec_t

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    That's encouraging. Thanks.
     
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