Is it bad to leave the charger plugged in to the wall while not charging anything?

Discussion in 'MacBook Pro' started by -A113-, Nov 16, 2015.

  1. -A113- macrumors newbie

    Nov 8, 2015
    I leave my charger plugged in to the socket but not actually turned on (Live in the UK, we have switches on the plug, turning off the switch is just like pulling it out of the socket) so have to crawl under my desk any time I need to charge the MacBook.

    It's kind of annoying crawling under the desk though so I'm thinking of leaving it on all the time (Not charging the Mac, just leaving the charger on) but I've always known it to be good practice to let chargers discharge before you unplug it all, so by just pulling the MagSafe off of the MacBook you're not letting it discharge and it'll damage it over time. I've also heard it still draws a small amount of energy.

    I don't know, maybe I'm being a bit pedantic here, why would it matter if it causes a slight bit of damage over time anyway? Just FYI this is a secondary machine (My iMac is my primary) so it spends most days in sleep mode in the case, the battery works really well and rarely needs charging.
  2. yukyuklee macrumors 6502


    Jan 4, 2011
    Boston, MA
    You can leave it plugged in and no need to worry about discharging anything. As long as you use the laptop once a week even with it plugged in the mac adjust its battery and if it needs to drain a little it will due to software built into the mac. Cheers!
  3. T5BRICK macrumors G3


    Aug 3, 2006
    My charger is basically never unplugged from the wall.
  4. Adamantoise macrumors 6502a

    Aug 1, 2011
    Of course. Engineering has come a long way. We have circuits to regulate all that stuff now.
  5. snaky69 macrumors 603

    Mar 14, 2008
    Mine's been plugged in for years on end with no ill effects.

    Chargers regulate all that by themselves now.
  6. takeshi74 macrumors 601

    Feb 9, 2011
    That's it really.

    How do you "know" this? Source?
  7. fisherking macrumors 603


    Jul 16, 2010
    ny somewhere
    -A113- said:
    "I've always known it to be good practice to let chargers discharge before you unplug it all, so by just pulling the MagSafe off of the MacBook you're not letting it discharge and it'll damage it over time."

    really, that makes no sense. the charger has no 'idea' of how much it's charged the battery (only the battery knows...)
  8. Toutou macrumors 6502a


    Jan 6, 2015
    Prague, Czech Republic
    This is certainly true, but that "small amount" is more like zero point zero zero nothing. Don't worry, leave it plugged in. Just like every other piece of electronics, your monitor, your TV or your iMac. I never unplug mine, I'm too lazy to crawl under the table.
  9. waquzy macrumors 6502


    Sep 9, 2013
    Leicestershire, UK
    Same here
  10. -A113- thread starter macrumors newbie

    Nov 8, 2015
    Thanks for all the replies! Sorry for this late response. Not sure where I heard about needing to let chargers discharge onto something, I think I was just watching some tips on taking care of your camera and they mentioned letting the charge light go off before actually removing the battery, something about it being bad for the capacitors inside the charger to store energy like that.
  11. Rustrans macrumors newbie

    Nov 26, 2015
    There could be another problem though. Does this present a fire hazard problem?
    If by accident you manage to somehow short the pins on the loose end of the charger then you get electrocuted or cause a fire.
    I don't even know if it is a viable concern for macbooks' chargers so this is really a question, not a statement.
  12. priitv8 macrumors 68030

    Jan 13, 2011
    They should have a short-circuit protection. Also, voltages around 12V (ok, the 85W model puts out 18V if I'm not mistaken) can not electrocute anyone.
  13. Aneef macrumors regular


    Jun 4, 2015
    Lahore, Pakistan
    There is no harm in leaving the chargers connected to the wall. The charger adapter is merely an AC to DC converter, it merely supplies DC (Current) to your laptop. If the battery is drained, current (flow of electrons) would start accumulating in the battery. When the battery gets full, the charging the battery circuitry gets cut off and now the laptop just runs on the DC Supply. Hence, when the Macbook is not connected to the charger (but charger is on), the electron flow(current) isn't happening(flowing) so there would be no energy dissipation. The only little energy dissipation would be of the internal resistance in the AC to DC conversion circuitry but it'd be in the order of micro-watts perhaps
  14. c1phr macrumors 6502

    Jan 8, 2011
    I've had the same charger plugged in for the better part of the last 5 years, and it's still going fine. For the most part, I only unplugged it to move (I was a student during that time, so I moved every few months).

Share This Page