Lithium Ion Battery Powered Devices - Leave Plugged In To Prolong Battery Life?

Discussion in 'Mac Basics and Help' started by shoehornhands, May 21, 2015.

  1. shoehornhands macrumors regular

    Oct 9, 2014
    Consider any MacBook laptop powered by a lithium ion battery. Assuming proper care / maintenance, if you leave it plugged into the wall while using it, the battery will last longer (i.e. you'll go through fewer charge cycles and won't need to replace it as often) than it would if you use it off charger and only plug it in when the battery runs low.

    Is this behavior a property of lithium ion batteries themselves, or does it have more to do with a specific way laptop batteries are engineered?

    For example, I have both an iPhone and a pair of headphones that use a lithium ion battery as well. Both devices can be charged via a USB port. Will these devices exhibit the same behavior as a MacBook in terms of battery longevity, or are they engineered differently?

    Put another way, is battery wear and tear primarily a function of charge (i.e. 100%, 75%, 25%) or can electrons still move through the battery on a full charge, in such a way as to constitute usage of charge cycles (for example, maybe the rate at which the battery is charged is equal to the rate at which a battery is discharged)?

    Anyway, I wasn't really sure exactly how to ask this, so hopefully you can make out what I'm trying to get at.

  2. shoehornhands thread starter macrumors regular

    Oct 9, 2014
    Anybody have any info on this?

    I use my headphones with my MacBook Air all the time. If I leave them plugged into my MacBook's USB port (to keep the lithium-ion battery fully charged) whenever I'm using them with the MacBook, will it increase the life of the battery, or does it still go through charge cycles?

    In other words, are the lithium-ion batteries used in all consumer electronics (i.e. headphones, phones, wireless computer peripherals, etc), engineered the same way as laptop lithium-ion batteries (i.e. if used while plugged in, do they circumvent the battery thus prolonging the lifespan of the battery / avoid using up charge cycles like a laptop does when plugged into the wall)?
  3. Toby Goodbar macrumors 6502

    Sep 8, 2006
    I was under the impression that for both iPhone amd MacBook there's a controller chip that stops the battery from "charging" or what we call cooking or boiling a battery in the non lith automotive world. With that said in my subjective experience it seems that laptops that stay plugged in all the time seem to end up with useless batteries faster.

    It seems like most people I know stay tethered to the cord to save battery longevity but then one day they unplug only to discover that battery doesn't work anymore.

    I realize that none of that is exactly scientific but I hope it helps
  4. redbear1958 macrumors newbie

    Aug 4, 2010
    I leave my macbook plugged in most of the time. The battery will last longer. The more complete charge cycles will shorten the life. I listen to Leo LaPorte The Tech Guy and that is what he recommends.
  5. shoehornhands thread starter macrumors regular

    Oct 9, 2014
    Thanks, appreciate the info.
    Yeah, with most laptop batteries I think the general recommendation is to make sure you run it down maybe 20-30% every week or so to keep the electrons moving (assuming you leave it on charger all the time). Assuming you take these necessary precautions though, I think keeping it plugged in only prolongs the battery life.

    When you mention a "controller chip," that's exactly the sort of thing I'm wondering about. It sounds like laptop batteries might be engineered a bit differently (with the idea in mind that they're likely to be used quite often while plugged in). I'm thinking it might not be a good idea to assume for example, that my headphone lithium-ion battery will behave in the same manner.

    Yeah, this has been my experience as well with laptops. I'm just not sure if other lithium-ion powered devices behave the same way (e.g. if it's a good idea to leave my headphones plugged into a USB port while using them (they charge via USB), to extend the life of the headphone lithium-ion battery).

    Hopefully there's an engineer or battery expert out there that can chime in.
  6. Toby Goodbar macrumors 6502

    Sep 8, 2006
    This may help.
  7. shoehornhands, May 25, 2015
    Last edited: May 25, 2015

    shoehornhands thread starter macrumors regular

    Oct 9, 2014
    Thanks, this article definitely sings a bit of a different tune than what I've been going by. When it says "ideally everyone would charge their batteries to 80 percent then let them drain to about 40 percent," it makes me wonder why they don't just design the batteries or the computer to utilize the battery in a more efficient way (assuming this is possible). Of course, it could be as simple as marketing (i.e. an additional hour or two of battery life probably sells more laptops than 2,000 recharge cycles).

    Anyway, I'll have to read up on this stuff some more, but it sounds like it's of little (if any) benefit to leave my headphones or iPhone on the charger for any reason other than charging the battery. There sure is a lot of contradictory information out there.

Share This Page