MacBook Pro battery life

**jhatter** · 11-29-2012, 01:12 PM

Hi,

I use my MacBook pro for about 6-7 hours each day. I have had it for about a year now. Sometimes I have it plugged into the mains all day. Sometimes I work off the battery and let it run down. Sometimes I work until it runs out of battery and then I plug it into the mains again and start working again.

So as you can see there is no consistency to the way I charge, re-charge and run down the battery. Is this detrimental to the long-term life of the battery?

Thanks in anticipation of your replies.

( MacBook Pro 2.53, Intel Core i5 )

**bernie1227** · 11-29-2012, 06:14 PM

This article here basically explains your question in terms of what way to charge:
http://www.zdnet.com/blog/apple/the-...s-battery/4310
While this is a link to Apple, explaining themselves how to charge your battery:
http://www.apple.com/batteries/notebooks.html

The conclusion that I draw from these two websites, is that it's not a good idea to leave your MacBook plugged in all day, as that's just not how the battery's are designed to work, but instead to do cycles.

**jhatter** · 11-29-2012, 08:02 PM

Many thanks Bernie, now I know.

**djr33** · 11-29-2012, 11:53 PM

While I know nothing about how batteries technically work, that seems like a horrible design on the part of Apple.

Bernie's reply is correct. I've been told the same thing. You're supposed to let the battery run down then recharge it.

Or, more generally, you should USE the battery to preserve it, rather than overcharging it.

Why there isn't some feature of the $2000+ computer that fixes this.... I don't know. But that's apparently the case.

It's inconvenient when you want to use the computer in real life-- good to charge it in case you'll be moving it around, rather than just letting the battery go down while you're sitting with the power adapter right next to you.

And for the record, the battery life is, I think, somewhere around 300 cycles. At least I think they said "cycles". I don't think it's literally 300 charges because obviously that would run out pretty quickly. But there's some measure they have I suppose.

**bernie1227** · 11-30-2012, 04:58 AM

Originally Posted by djr33

And for the record, the battery life is, I think, somewhere around 300 cycles. At least I think they said "cycles". I don't think it's literally 300 charges because obviously that would run out pretty quickly. But there's some measure they have I suppose.

It's 1000 full cycles actually.

**djr33** · 11-30-2012, 12:07 PM

Maybe for the new batteries that it's. I know they said 300 a couple years ago with my older mac.
And a "cycle" is just a full use of the battery? That doesn't seem like much at 300x2hrs (old mac), although 1000x5hrs isn't too bad this time around, although realistically it's probably 1000x2.5hrs as the battery life gets lower over time.
So, including time it's plugged in, you get something like 5,000 hours out of a battery? Does that seem low?

**bernie1227** · 11-30-2012, 08:02 PM

I know for a fact that MacBook is meant to do 7-8 hours on a single charge, so were looking at a bit more than 5000 hours.

**djr33** · 12-01-2012, 03:10 AM

Unfortunately, that statistic is incredibly misleading. Fresh out of the box the computer will do around 80-90% of what it claims to do. Note that it's probably actually realistic-- it would do close to 100% if I was using the computer very lightly-- maybe typing a plain text document and nothing else, with the screen dim. So, ok, fair enough.
And that lasts for a while. Then after a while of use, I'd say around 6 months, the battery life goes way down. Now it's been well over a year for me and it's a fraction of what it used to be. But at least that fraction is still around 2 hours. With my old one by this time it was about 30 minutes.

So, from the two computers, here are the stats:
Original: 2.5hrs; after a year or two: 20-30 minutes
Original: ~5hrs; after 1.5 years: ~1-3hrs

It's still pretty usable at 1-3 hours. At least a big change from my last one. But it would be nice to actually have the advertised 5 hours back!

For the newest ones that claim that much battery life, I'm sure it's the same. They'd get down to 3-4 hours within a year or two. That's not too bad, though.

**bernie1227** · 12-01-2012, 04:38 AM

Originally Posted by djr33

Unfortunately, that statistic is incredibly misleading.

I wouldn't say it's misleading at all, mainly because in an ideal situation it does do exactly what it says on the box. With anything like this, you're going to have to be prepared for slightly less than it says. A good example here is an iPad. After a year of use, I can still get the full advertised 10 hours out of it.