What happens if you overcharge your MacBook Pro?

I've recently been reading (from a lot of sources!) that overcharging battery-operated devices ruins the batteries.

This came to be true for my brothers Acer laptop - the battery is ruined, and we have to use the power adaptor all the time.

However, before I knew that you shouldn't overcharge, I overcharged my iPhone 3GS A LOT. Every night for over 2 years it's been on charge all night and it only takes a few hours for it to get up to full battery. I haven't noticed any significant decrease in daily battery life, and...its fine!

So now I'm confused. Are the batteries that Apple use unique in that overcharging them makes no difference?

Or is it that overcharging mobile phone batteries makes no difference (as opposed to laptop batteries)?

What I really want to know, is what happens if I charge my MacBook Pro for too long?

Will it's battery life shorten like my brother's laptop or will it make no difference as with my (Apple) iPhone 3GS?

Mate there isn't anyway to overcharge your Mac, period. I leave my MBP on 24/7/365 unless I'm travelling and do a Apple Portables: Calibrating your computer's battery for best performance once every couple of months to keep the health of it up.
Thats about the gist of it anyways

Cheers

TattooedMac said:

Mate there isn't anyway to overcharge your Mac, period. I leave my MBP on 24/7/365 unless I'm travelling and do a Apple Portables: Calibrating your computer's battery for best performance once every couple of months to keep the health of it up.
Thats about the gist of it anyways

Cheers

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Cool, thanks for the info.

So you haven't noticed any decrease in battery life? That's pretty good then! I'll now feel safe leaving it on charge all night...with my trusty 3GS

You should see no real issues with the iPhone or the MBP.
Apple - Batteries

I can't speak for the Acer laptop, but most modern battery-operated devices have intelligent charging built into them. That is, there is logic that controls how the battery is charged and won't continue to charge when it isn't needed.

With that said, batteries are "consumables", that is, they have a finite lifespan. There are ways to prolong that lifespan, such as following the advice from Apple and occasionally allowing them to drain fully and then recharge fully, but for the most part, your battery will eventually no longer hold a charge over time and will need to be replaced. Generally speaking, that shouldn't happen on a Mac laptop for about 5 years of normal use.

Cool thanks for the tips guys! Here's a nice video about how mac and iOS batteries:

MacMost Now 576: Don’t Stress About Batteries

It is imposible to "Overcharge Your Mac" so don't worry your macbook is fine!

MacAddict. said:

It is imposible to "Overcharge Your Mac" so don't worry your macbook is fine!

Click to expand...

Is there an echo in here?

Well, I'm going to be the odd one out here and disagree with the assessment which has been made, even if said assment links back to apple.com. Though if you read the article, nowhere does it say that it's ok to leave it plugged in. It simply states that IF YOU DO leave it plugged in all the time, to calibrate it every now and again by discharging it completely.

Now for a different take. Every Genius I've asked has said that the overall health and longevity of the battery is negatively affected by leaving the charger plugged in. I've been told that to get the most out of a MB/MBP/Air battery, to charge it at different intervals and times, and to never leave it plugged in after the charge is full.

A full charge cycle depends on how run down the battery is, and how much it is topped up, so if you just kind of trickle charge when it is in the middle of its cycle, it won't count as a cycle.

I suppose however that one must find these things out for themselves, and the only way to do that is through time. Also take into consideration that as time moves on, technology tends to change as well. So what may have been true about how OS X handled power management a year ago, may not be totally true now.

Doug

Well, to answer,

what happens if you overcharge your MacBook Pro?

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The battery ends up expanding. Sometimes it can explode, catch fire, and cause damage to near by things. With that said, this can happen to any battery that has a short, or some other problem where the charger fails to measure when the battery is full.

Leaving the computer plugged in does not mean your battery is getting overcharged.

Doug b said:

Every Genius I've asked has said that the overall health and longevity of the battery is negatively affected by leaving the charger plugged in.

Click to expand...

Every "genius" you've asked is incorrect. My battery continued to keep 96% of its original charge for more than three years despite being plugged in 99% of the time (I really use it mostly as a desktop). I checked it regularly with Coconut Battery and on those occasions when I did use the battery, I let it drain completely and then charged it back up again (or "recalibrating" as Apple calls it) but didn't do that very often (maybe three times a year). I also did this as one of the first things I did when I got the machine.

In the last year it has started to swell and deteriorate, but again it's now 4.5 years old (and yet still functions, albeit now it's losing its capacity fairly rapidly).

I admit my case is just one data point, and could be a fluke, but it's my own personal first-hand account that disproves the "conventional wisdom."

Side note: today's battery technology is rather different to my 2007 battery so I'm not suggesting you ignore Apple's advice.

My philosophy has been that although the battery isn't the cheapest thing in the world to replace, it's one of the easiest -- so I never worried to much about it, but ended up with a battery that went almost four years with no discernible depreciation in performance until fairly recently (I used to get ~3 hours of normal activity, now I get ~1 hour).