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kabooya

macrumors newbie
Original poster
Oct 18, 2008
11
0
hey i just got the new macbook and am wondering if i can leave the magsafe charger plugged in, or does it hurt the battery.
 
sorry i'm a bit new here, so i never saw the earlier posts... i have some questions:

1. if the battery is fully charged and you leave it plugged in, won't that be overcharging the battery and won't it decrease the battery's longevity?

2. if you charge the battery only halfway and have to stop charging because you need to bring the laptop away from the power source, does that decrease battery longevity also?

3. i heard that lithium batteries should never be completely discharged. so is it advisable to start charging when your power falls to 20% and not let it completely discharge except to callibrate it every few weeks?
 
If your battery is fully charged the computer should bypass the battery and only deliver a trickle charge which is due to a battery naturally losing a charge over time.
 

Standard Maintenance

For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Apple does not recommend leaving your portable plugged in all the time. An ideal use would be a commuter who uses her MacBook Pro on the train, then plugs it in at the office to charge. This keeps the battery juices flowing. If on the other hand, you use a desktop computer at work, and save a notebook for infrequent travel, Apple recommends charging and discharging its battery at least once per month.

doesn't this contradict what you guys advised earlier?
 
sorry i'm a bit new here, so i never saw the earlier posts... i have some questions:

1. if the battery is fully charged and you leave it plugged in, won't that be overcharging the battery and won't it decrease the battery's longevity?

2. if you charge the battery only halfway and have to stop charging because you need to bring the laptop away from the power source, does that decrease battery longevity also?

3. i heard that lithium batteries should never be completely discharged. so is it advisable to start charging when your power falls to 20% and not let it completely discharge except to callibrate it every few weeks?

1. The battery has a power controller built in meaning that it knows when it is fully charged and stops charging. From that point on the computer runs off of the magsafe only.

2. Because it is a lithium battery it has no memory meaning you can charge it to any percentage anytime.

3. Your MacBook will go to sleep at around 5% power so you shouldn't worry about fully discharging the battery.

Just make sure that you calibrate it once a month. If you want to see battery stats you can get a program called coconutbattery. It will tell you things like current capacity versus original capacity.
 
Standard Maintenance

For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Apple does not recommend leaving your portable plugged in all the time. An ideal use would be a commuter who uses her MacBook Pro on the train, then plugs it in at the office to charge. This keeps the battery juices flowing. If on the other hand, you use a desktop computer at work, and save a notebook for infrequent travel, Apple recommends charging and discharging its battery at least once per month.

doesn't this contradict what you guys advised earlier?

the key words there are "all the time". its ok to leave it plugged in overnight say or for a couple of days if at a desk. just make sure your calibrate it once a month. you may need not to calibrate it anyway if your using it mobile as depleting the battery will count as a calibration. also be aware that the ultimate killer of a lithium battery is charge cycles.
 
the key words there are "all the time". its ok to leave it plugged in overnight say or for a couple of days if at a desk. just make sure your calibrate it once a month. you may need not to calibrate it anyway if your using it mobile as depleting the battery will count as a calibration. also be aware that the ultimate killer of a lithium battery is charge cycles.

Exactly. Apple's use of "all the time" is really confusing and misleading. Leave it charged at night and when you're at your desk, only disconnect it if you're going to class or want to take it outdoors, but if you have the opportunity to charge it to 100% and leave it there while you're working that's the best.

This way you don't cycle you're battery too much, and increase its longevity. Someone at an Apple store told me I should be cycling my battery all the time, so every time it reached 100 i pulled the plug. What happened? My battery wouldn't last longer than 40 minutes (with brightness on minimum, wifi off, and no programs running besides Word).

So let it charge and leave it there! Only unplug if necessary, keep the cycle's low!







*just don't leave it charging for weeks straight
 
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