newbie question about battery life

[McBayne]

I have a macbook pro, and rarely take use of the portability having a laptop, especially since i'm not at college now. basically I have my power cord in 99% of the time and it's always charged.

yesterday my friend came over who also has a macbook and she said that always having the power cord in at all times isn't great for the battery life and my battery would be better off if didnt have it plugged in all the time and would use the cord for recharging when needed. she's not all that computer savvy but seemed semi confident about this.

is she wrong? correct? somewhere in between? etc

 

[eric]

yep, she's right. a constant flow of electrons is better for the battery. feel free to yank the cord occasionally. i usually let mine dip to between 30 and 50% a couple times a week or less. very occasionally you should also do a full discharge to calibrate the battery.

check these links:
http://www.apple.com/batteries/
http://www.apple.com/batteries/notebooks.html
how to calibrate a notebook battery

 

[core20]

just use your laptop more outside of your room with the battery as the primary source

 

[MinaMACMan]

Eric is correct.

The Power being hooked up all the time prevents the battery from doing what its meant to do correctly (Electrons flow) so it does weaken it over time. So the occasional discharge and then charge back up is a good exercise to keep the battery in a Healthy Condition.

Cheers

 

[Kyomii]

I am afraid I disagree. It is a common misconception. Another Mac forum where I work on, the administrator runs his laptop without charging it and then charges it when necessary.

However, when I challenged him about this, because he said it was better for the battery, it turns out that my battery has kept its almost new state, and his is can only charge to 59 percent of what it was as new.

His laptop is two years newer than mine AND he is on his second battery. My G4 powerbook can be charged to 94 per cent of its original maH capacity and it is over 3 years old - still on first battery.

I have always kept mine plugged in and then once a month I let it completely drain to calibrate it and recharge it.

I have done this with every laptop I have owned, and never ever had an issue with laptop batteries. I have a 5 year old laptop that is perfectly fine with its original battery also - very little degradance in performance.

It is up to you, but remember a battery only has so many charge cycles - so the more you are charging it the sooner you will have to buy a battery.

So, in essence, recharging the battery weakens it, not the other way around.

You can check the capacity of your battery (or what is left of it) using http://www.coconut-flavour.com/coconutbattery/

As long as you discharge it once a month you should be fine.

 

[qwinkan]

can someone else confirm kiyomii?

 

[MaDDoG]

Thanks guys. I too keep it plugged in 99% of the time. I have noticed recently that it has dropped from 100% down to 96% charged even though its plugged in.
I have just pulled the umbilcal cord and am discharging......I feel scared......

 

[Kyomii]

Thanks guys. I too keep it plugged in 99% of the time. I have noticed recently that it has dropped from 100% down to 96% charged even though its plugged in.
I have just pulled the umbilcal cord and am discharging......I feel scared......

This is normal behaviour. Remeber every dishcarge means a cycle is used charging - a battery only has so many charge cycles before it dies.

This link will tell you what you are seeing is normal:

http://docs.info.apple.com/article.html?artnum=88344

I wouls advise now thought that you let your device discharge right down before plugging it in again as this will callibrate it anyway

 

[DoubleCap]

I am afraid I disagree. It is a common misconception. Another Mac forum where I work on, the administrator runs his laptop without charging it and then charges it when necessary.

However, when I challenged him about this, because he said it was better for the battery, it turns out that my battery has kept its almost new state, and his is can only charge to 59 percent of what it was as new.

His laptop is two years newer than mine AND he is on his second battery. My G4 powerbook can be charged to 94 per cent of its original maH capacity and it is over 3 years old - still on first battery.

I have always kept mine plugged in and then once a month I let it completely drain to calibrate it and recharge it.

I have done this with every laptop I have owned, and never ever had an issue with laptop batteries. I have a 5 year old laptop that is perfectly fine with its original battery also - very little degradance in performance.

It is up to you, but remember a battery only has so many charge cycles - so the more you are charging it the sooner you will have to buy a battery.

So, in essence, recharging the battery weakens it, not the other way around.

You can check the capacity of your battery (or what is left of it) using http://www.coconut-flavour.com/coconutbattery/

As long as you discharge it once a month you should be fine.

I can confirm this. As you all know, electrons flow from the negative to positive terminals on the battery. This will produce a chemical reaction. Otherwise, it won't. So... leaving it hooked up all the time is no big deal. The main thing you must worry about is charge cycles, as said above. After a while, it won't be able to hold a charge as long as it previously did.

 

[eric]

i think kyomi is missing the difference between shallow cycles and deep cycles. continuously draining the battery to 10 or 20 percent is not good, but many shallower cycles keep the electrons flowing in a healthier way.
and actually in some way leaving a notebook on a charger, does this. it lets the battery cycle in extremely shallow cycles constantly since the power management system only kicks in when the battery drains a bit (why you'll often see the battery at less than 100% when it's connected to the wall power).

 

[MaDDoG]

Well I can say I have done it. Discharged the battery fully and then recharged. Now it shows 100% again.

 

[Kyomii]

i think kyomi is missing the difference between shallow cycles and deep cycles. continuously draining the battery to 10 or 20 percent is not good, but many shallower cycles keep the electrons flowing in a healthier way.
and actually in some way leaving a notebook on a charger, does this. it lets the battery cycle in extremely shallow cycles constantly since the power management system only kicks in when the battery drains a bit (why you'll often see the battery at less than 100% when it's connected to the wall power).

No, I am not missing any difference between shallow cycles and deep cycles.

To use your notebook until the battery drains every day and charge it up every day is a big mistake and will result in having to replace the battery before its time.

Like I said, and prpandey has kindly confirmed, a battery only has so many charge cycles, once they are used, dead battery.

I have never had to replace a notebook battery yet - my oldest notebook is over five years old.

I also posted the link above to the Apple site which explains why the battery shows less than 100 per cent, it is perfectly normal and has little effect on life of battery.

 

[Bookworm]

I didn't know if I should start my own thread or add to this one. Since my question relates to batteries, I decided to add.

I'm about 99% there in terms of buying a Mac! I'm so excited at the prospect I'm just about peein' myself! I do have some questions though. I have encountered comments about the battery life in this and other forums.

My only experience with laptops is of the PC variety. I rarely use the battery for mine, I just keep it plugged in without the battery inside. Can the same be done with a MacBook Pro? Or is the battery always to be kept plugged in unless/until it needs replacing?

Thanks, in advance, for your help!

 

[iKitten]

Because of the nature of Magsafe, it isn't a good idea to keep it plugged in without battery in place. I read about someone using a MagStay Pro for that purpose. I can't tell you whether or not this is healthy, but perhaps somebody else around here has experience?!

 

[eric]

well kyomi, we can agree to disagree, and i think we may both have some experts or anecdotal evidence on our sides.

 

[walmartconnect]

Besides the weekly/monthly complete discharge to calibrate, I have to disagree with you eric .

The batteries in our macbooks do not function as the old batteries of days gone by do. They do not need to be constantly discharged and recharged to keep the electrons flowing.

I am on my second battery, my first one was used to near death every single day (class, I always sit in the front away from outlets ). That battery's capacity dwindled much more quickly than this one (plugged in all of the time as I am not in school right now). I completely discharge it once every two weeks for calibration's sake. I'm still testing this theory, but so far it seems pretty accurate.

 

[proxy]

mine is just about always pluged in when i am using it as i will not shut it down that much and just close the lid or turn display off if i am downloading something or redering or something

and i have not found any problems with my battery and its just about always pluged in the battery has done 162 cycles in about 5 months or so

and tbh i dont plan on having this macbook for more than another 6months as i like to upgrade to bigger and better things and the new pros look to good to miss.

 

[shahvikram123]

I've had 173 cycles and I've had my macbook for 7 months now.
I normally use it by leaving it plugged in via the mains power, however about once a week I leave it unplugged and wait for the message to come up which says that your battery is running low, I then plug in the magsafe power cord

Is this how I'm supposed to use my battery? will using it like that shorten the overall battery life?

 

[DoubleCap]

I'm am an electrical engineering, if that helps my credibility