I watch a lot of movies streaming online. Should I keep my computer on the power cord, or should I charge the unit completely, remove the power cord, then wait till it gets to a low battery and plug it in again?

My main concern is that if I keep it plugged in, it will degrade the life of the battery, but if I keep plugging and unplugging, it will cycle through the battery life anyways.

My question is essentially: Should I keep it on the charger when doing something that would cause the battery to drain faster than normal?

  • I'm sorry but how is the streaming of the movies relevant?
    – Gerry
    Commented Aug 28, 2012 at 8:28
  • @Gerry Becausw when I'm streaming video, or watching a video offline, it eats the battery a LOT quicker than when I'm not watching a video. Commented Aug 28, 2012 at 13:33
  • Why do people insist on changing what my question is about? I wanted the streaming aspect specifically because thats the only time I would consider having it on the charger...My question was about whether I should keep it on the charger when doing something that would cause the battery to drain faster than normal. Commented Aug 28, 2012 at 14:07

2 Answers 2


To get the most out of your MacBook's battery, follow the Notebook Battery advice from Apple: unplug and use your battery until empty about once a month, then charge back up to full. Your question expands a bit on another question on the site about general charging:

Should I disconnect my MacBook Pro's power cord when the battery is fully charged?

In your case, streaming video is usually a high power usage event that can drain a battery in 4 or 5 hours. You will therefore be more likely to have a higher recharge cycle count than someone that isn't using as much power. For that reason, I would try to keep it plugged in when running. Everything is a balance, and it would be hard to reach the 1000 recharge cycles design lifetime of the new batteries in Apple portables - but as long as you are once a month draining it down, you might be better off keeping it on power the rest of the time it runs just in case you reach that limit before you are done with using the Mac.

  • The first place I went to was the site you linked to get info about my battery. My question was about whether I should keep the computer on the charger when doing things that would drain the battery faster. Commented Aug 28, 2012 at 14:08
  • In this situation, do what best suites your needs. Apple provides no guidance about whether it is better to drain a battery quickly or slowly. The only guidance Apple provide about batteries is in the link above; anything else is conjecture and personal preference. Commented Aug 28, 2012 at 14:40

Well, Apple does not recommend leaving your portable plugged in all the time, as for a lithium-based battery, it's important to keep the electrons in it moving occasionally. MacBook / Pro, though, are designed to deliver up to 1000 full charge and discharge cycles before it reaches 80% of its original capacity.

A charge cycle means using all of the battery’s power, but that doesn’t necessarily mean a single charge. For instance, you could listen to your iPod for a few hours one day, using half its power, and then recharge it fully. If you did the same thing the next day, it would count as one charge cycle, not two, so you may take several days to complete a cycle. Each time you complete a charge cycle, it diminishes battery capacity slightly.

Since 2009-2010 laptops carry a technology called Adaptive Charging which basically is a chip within the battery that talks to its cells monitoring everything from charge level to temperature. The chip relays this information to the computer, which uses an advanced algorithm to determine the optimal charging current. Adaptive Charging reduces the wear and tear on the battery giving it a lifespan of up to 5 years.

So, I'll actually won't worry that much about the battery. Just try not to keep it plugged all the time, and remember to do a full charge cycle at least once per month.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .