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DragonboyLy · Sep 4, 2006, 04:14 PM

Does anyone leave their macbook constantly plugged into a power source? It uses a lithium rechargeable battery so would keeping it plugged reduce the battery life?

mduell · Sep 4, 2006, 04:18 PM

Leaving it plugged in all the time is fine. To keep the battery conditioned you should run through one battery cycle every month.

ghporter · Sep 4, 2006, 04:39 PM

Constantly plugged in is not harmful at all, but as mduell says, it doesn't keep the battery "in shape." The charge/discharge curve is not always the same on a Li-ion battery, so if it never gets a chance to run down significantly, the computer won't know exactly how the battery is doing. And it does seem to help performance of these batteries if you run them down now and then.

But the only bad thing about leaving your MB plugged in all the time is that you use a few watts of power that do nothing productive, and when you add all the other "instant on" and "warm-off" devices in your home that comes to a lot of watts and a noticable amount of heat that you get absolutely nothing for. I try to keep such charger-type devices unplugged when I'm not using them, to at least reduce my parasitic electricity usage.

mac_pc · Sep 4, 2006, 09:33 PM

Does any macbook users here leave their macboos on all the time? Is it ok do to so? Would this decrease the life of the macbook?

When you turn the macbook off, is it asleep or actually turned off? I am thinking about this because of the Ipod functions.

ChrisF · Sep 4, 2006, 10:51 PM

I've almost entirely used my Powerbook G4 on AC since I got it in spring 2002. I've never run the battery down to "condition it" and with 69 cycles on the battery, it still has 3580mAh capacity, and runs the computer for a couple hours when I need it to.

cbrfanatic · Sep 4, 2006, 11:07 PM

i bought my pb in august 2005, ive had 168 cycles, and my battery only last about 2 hours, sometimes more if i get lucky. im currently using it on the ac with my external monitor as i wait for my free replacement from apple. its been plugged in and running since september 1st.

mac_pc · Sep 4, 2006, 11:08 PM

what is supposed to be the FULL mah capacity?

So leaving your computer with ac adapter and on will definitely hurt you for portability?

The best way would be to turn it off every night with the ac adapter unplugged when there is still battery left right?

cmeisenzahl · Sep 5, 2006, 09:56 AM

Originally Posted by mduell

Leaving it plugged in all the time is fine. To keep the battery conditioned you should run through one battery cycle every month.

Agreed, every couple months I let the battery run all the way down and then fully recharge it.

Big Mac · 10:49 AM

Lithium batteries have a finite number of charge cycles. Their capacities degrade gradually, through their lifetimes, due to the cycles and other factors. By leaving a battery charging all the time, the system has to run the battery down a small amount every so often, thereby costing a charge cycle periodically. Therefore, it is a good idea not to leave a battery charging all the time. I try to charge my batteries, use them until they're nearly discharged, and then charge them again. It's not something you should worry about too much, but if you keep that general info in mind you'll have better long term battery performance and longevity.

tooki · Sep 5, 2006, 01:23 PM

That is bad advice.

LiIon batteries are best served by being held at 40% charge level. No computer I have ever seen allows this. The next-best thing is to keep them fully charged. This is what a Mac does.

The worst thing you can do is to run it down all the time. THAT is what damages LiIon cells the most. An occasional full discharge to re-calibrate is advisable, but beyond that, keep it plugged in so that it stays at full charge.

Note that the Mac will not start recharging until the battery level dips below 95%. So it's really only topping it off every few days if it's left plugged in constantly.

tooki

Stecchino · Sep 5, 2006, 05:40 PM

Don't forget Apple's official battery info web page as a good reference.

Apple - Batteries

Dillon-K · Sep 5, 2006, 06:13 PM

wait so will my battery go down if I use my battery 50% of the time?!

SLiMeX · Sep 5, 2006, 06:27 PM

Originally Posted by tooki

That is bad advice.

LiIon batteries are best served by being held at 40% charge level. No computer I have ever seen allows this. The next-best thing is to keep them fully charged. This is what a Mac does.

The worst thing you can do is to run it down all the time. THAT is what damages LiIon cells the most. An occasional full discharge to re-calibrate is advisable, but beyond that, keep it plugged in so that it stays at full charge.

Note that the Mac will not start recharging until the battery level dips below 95%. So it's really only topping it off every few days if it's left plugged in constantly.

This is confusing. You make it sound that if you're a potential student, your notebook won't have such a fulfilling life as a Macbook that sits on a counter all of its life. So now I'm confused.

Twice a week I bring my Macbook to school, running the battery down to less than 15% each of those two days. I'm actually damaging the battery?

Also, isnt this what these notebooks were made for?

iREZ · Sep 5, 2006, 06:33 PM

just use your battery as you wish...if it gets unusable go buy a new battery.

it's (the battery) not going to last forever. with that said, keep it charged and plugged in when you can and try to calibrate once every three weeks or so.

Googer-Giger · Sep 5, 2006, 07:24 PM

Originally Posted by Dillon-K

wait so will my battery go down if I use my battery 50% of the time?!

With Lion batteries, it doesn't matter how you use the battery, if you hardly ever use the battery, the life declines over the years.

mduell · Sep 5, 2006, 09:08 PM

Big Mac: According to Apple, partial cycles don't count as a full cycle. Going from from 90% to 100% ten times is 1 cycle, not 10.

Originally Posted by tooki

That is bad advice.

LiIon batteries are best served by being held at 40% charge level. No computer I have ever seen allows this. The next-best thing is to keep them fully charged. This is what a Mac does.

The worst thing you can do is to run it down all the time. THAT is what damages LiIon cells the most. An occasional full discharge to re-calibrate is advisable, but beyond that, keep it plugged in so that it stays at full charge.

Note that the Mac will not start recharging until the battery level dips below 95%. So it's really only topping it off every few days if it's left plugged in constantly.

tooki

Does this also apply to LiPo batteries?

Big Mac · 06:24 AM

In regard to my previous post, the fact is that sources differ concerning proper charging strategies of LIon battiers. The information that I based that post on came from previous research (including an older thread on the forums that I contributed to with research from various sources) and personal experience with LIons of different types in different devices.

I used to frequently recharge various systems, and I ended up with poor battery life. My iBook's second battery has lasted (with a decent capacity) much longer than its original battery did, which I recharged much more frequently. I was incorrect when I said that every small discharge causes a loss of a cycle, but all of those tiny recharges and discharges do have a cumulative effect. The other important thing to consider is that, according to recent studies, a lot of battery life is expended due to excess heat. Charging causes additional heat; even more heat is produced when charging is coupled with active use. So there's another good reason to avoid constantly charging a battery. LIon batteries like to be stored at around 40% charge, but that refers to storage, not active use. I stand by the general theme of my previous post, but YMMV.

Standard Maintenance - Apple - Batteries - Notebooks

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

Improving the Longevity of Lithium-Ion Batteries

According to Brian Kimberlin of Panasonic Battery Corp., one of the best strategies to prolong the life of batteries is to use them so they don't lose their capacity to hold a charge. "Leaving a notebook charged all the time is not a good idea," said Andrew Bradner, senior product manager for APC, a maker of charging devices. To prolong battery life, it is best to use the battery and wall current alternately to run the laptop.

According to Michelle Thatcher, a senior associate editor at CNet.com, if you only use wall current to run the device, you should remove the laptop's battery to prevent it from being constantly charged and from becoming overheated.

ghporter · Sep 6, 2006, 08:15 AM

Lithium-polymer battery technology is pretty new, so I don't think anyone has enough real-world experience to say whether it works just like LiIon technology, but it should. The polymer matrix is supposed to be just a different method of applying the electrolyte.

With that said, I still like the idea of unplugging a device that's not actively doing something, if for no other reason than it is not actively doing anything.

sieb · Sep 6, 2006, 08:42 AM

They will all loose charge over time/cycles regardless of what you do.. Leaving it plugged in all the time though is not bad. Letting it run down once in a while so it can do a full charge cycle is equally not bad. Letting it run down every day, can shorten the overall lifespan of the battery (were talking a couple years here).