Sidebar Sidebar
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

Safe to leave power cable on after a full charge?

Icaras

Icaras

macrumors 603
Original poster
Mar 18, 2008
6,349
3,396
Just wondering if its advisable to keep the magSafe connector hooked up the MBP after the battery is fully charged. Right now I just leave it, but I've always heard that on mobile devices, keeping the charger on after a fully charged battery might actually shorten the life span of the battery. Would this be the case for the MBP too?
 
I'm not positive, but i'd bet the farm that it would be just fine. I leave my PowerBook plugged in for days at a time when it gets to full charge within hours of being plugged in.
 
Yeah its fine. When I have mine plugged in for a few days it usually drops to 99% or 98%. I just unplug the charger run on battery for a little and let it charge back up. The battery is back at 100%. As long as you sometimes run on battery power its all good.
 
Icaras said:
Just wondering if its advisable to keep the magSafe connector hooked up the MBP after the battery is fully charged. Right now I just leave it, but I've always heard that on mobile devices, keeping the charger on after a fully charged battery might actually shorten the life span of the battery. Would this be the case for the MBP too?
Click to expand...

It stops charging at 100%. You'll be fine.
 
I've left my MBP plugged in a few days at a time. Your MBP shoul definitely be fine with this.

However, it will probably be a good idea to make sure you use your battery for at least one full charge cycle once in a while (Apple's support page for batteries recommends at last once a month, minimum). This should keep the battery in good shape.
 
it's safe.
but for your battery's sake, use your MBP on battery at least once a week. ad let it drain up to the lowest possible level up to the time your MBP falls asleep.

this will improve the life of your battery
 
Ah right. Or in Apple's notes, "Calibrating" the battery, I think. Great, thanks for the tips guys. :cool:
 
apfhex said:
I've left my PowerBook plugged in almost 100% of the time since 2002. :cool: Of course the battery doesn't work anymore. :eek:
Click to expand...

I'll chime in and say that I have similar results. I mainly use my Powerbook while it is plugged in, since 2004, and even after the monthly battery calibration the battery will only charge to 69%, so I get pretty abysmal unplugged times. Now I wouldn't necessarily attribute this to being plugged in all the time, but just giving a +1 to this type of case. Cheers.
 
Most of the more modern devices have battery technology that has a circuit that essentially shuts down input when it reaches full. This avoids "overcooking" the chemistry in the battery and hurting its overall life.

There were earlier technologies used in some older devices that did not have this feature. I believe these were Nickel Cadmium or maybe NiMH batteries used in some cel phones and computers, that did not have this feature and so you could indeed overcook the battery by leaving it plugged in all the time.

Since the advent of Lithium chemistry and the improving battery circuitry this is now a thing of the past.
 
I would let mine charger to 100% and then leave it connected for a while then just un-hook the cable and let it drain. After reading what you guys are saying seems it's safe to just leave it plugged in. My batteries health is at 97% after a month, give or take, almost of having the new Per. MBP.
 
You must log in or register to reply here.
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.
Top Bottom
Back