[jeff k]

I know that the laptop battery is like a muscle and needs to be exercised and drained once a month.
Besides that, it there any harm in having your laptop plugged in most of the time?

I've been trying to balance it having it go from 100% to 5%, then plug it in, then let it drain a bit, throughout the month.

But's it's a PITA and I often find it completely drains when you least want it to be drained.

[AKcrab]

Apple - Batteries - Notebooks

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 notebook 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. Need a reminder? Add an event to your desktop’s iCal.

[Lateralus]

Maybe this why my battery is all wonky. Its design capacity dropped from 90% to around 50% out of the blue a month ago, and fluctuates all over the place from 50% back up toward 90%

[Big Mac]

The answer to your question, can a laptop be plugged in too much, is absolutely 100% YES! Keeping a laptop with a battery plugged in most of the time will drain the life out of that battery because of excessive charging. If you want to enhance the longevity of a lithium ion battery, you should regularly run it on the battery and charge it frequently (don't let it run down too much too often).

Note that the non-removable batteries in Apple's most recent products fare better and last longer than the removable lithium batteries Apple used to use. They have the same enhanced lithium ion polymer battery type as the iOS devices and consequently have much greater longevity as far as holding battery capacity through high charge cycles.

[jeff k]

thanks Big, ok, I keep with my normal style which is to variate things a lot.
I'm using the laptop now as also a 2nd work station. I wish the man mini was only $200 new not $700!

So the laptops of the future will have non removable batteries you think?

I need a new one every 2 years currently.

[Waragainstsleep]

My Laptops rarely spend much time unplugged and I have yet to notice any issues with battery life that I don't believe would have arisen anyway due to age. Its one of the main advantages of owning a Mac laptop over Wintel. Leave an Acer etc plugged in overnight and you'll basically kill the battery more than likely.

Apple may not recommend it but I wouldn't lose sleep over it.

[ghporter]

The important part is to not JUST keep it plugged in all the time. USE the battery, and it will last a lot longer, both in charge time and in usable life.

[P]

This depends a little on the battery type, but for RECENT NiMH batteries, it works out like this:

* Each battery has about 500 charge cycles before it will stop taking charge. This is the reason why leaving it in all the time might be bad - if the battery has lost even 1% of a charge, it will start charging, using up one cycle. Apple has a policy to not charge the battery unless it has dropped below a certain threshold. For iPods, that's 80% charge - not sure if the Macbooks have the same limit.
* The battery meter will get confused if the battery is charged when not fully discharged, starting to show that the battery is partially empty when it's actually full, and that the remaining life is shorter than it actually is. Running the battery down to zero will correct this defect. HOWEVER...
* Running the battery down to zero is not good for lifetime. You can say that charging it back up from zero uses up two "charge cycles" instead of one, so this resetting should be done sparingly.

My policy has always been to leave the laptop plugged in when in use, but once I have removed it from the plug, I tend to run it down to about 20% charge before plugging it in again. It's the constant plugging and unplugging that is really bad for the battery life.

[jeff k]

P

"My policy has always been to leave the laptop plugged in when in use, but once I have removed it from the plug, I tend to run it down to about 20% charge before plugging it in again."

this is what I've been doing.

That alone can be very tiring.

If W if correct. If would be much more relaxing for me just to keep it plugged in except when I'm using it Mobile, which is rare these days. But again, you disagree with W, in that keeping it plugged in 96% of the time is not a great idea.

[SpaceMonkey]

Originally Posted by P 

This depends a little on the battery type, but for RECENT NiMH batteries, it works out like this:

* Each battery has about 500 charge cycles before it will stop taking charge. This is the reason why leaving it in all the time might be bad - if the battery has lost even 1% of a charge, it will start charging, using up one cycle.

I thought a "cycle" was the equivalent to a full discharge and charge. So in that scenario, you would have used up 1% of a cycle.

(And do you mean lithium-ion batteries, not NiMH batteries?)

[jeff k]

Guys, today, geez, I had the laptop on sleep, it was at 80% or so and by end of the day zeroed out! and it's a fairly new battery.
The ruins a whole cycle. Can't win.