[fuddman]

Hi, just a quick question, is it better the actually take the battery out of my Al'15 1.25 if I leave the AC plugged in day and night? I kinda feel that my battery life is shorter now... thanks for your help.

- fuddman

[Bonhomme7heures]

No, just leave it in. When the battery is in full charge and the laptop is plugged in, the powerbook takes it's power directly from the AC bypassing the battery.

No expert, I was asking myself the same question and got my answer using the search button on this forum.

[g4928]

An interesting read on Lithium Ion batteries:
http://www.batteryuniversity.com/parttwo-34.htm

More specifically:
"The question is often asked if one should disconnect the laptop from the main when not in use. With lithium-ion it does not matter. Once the battery is fully charged, no further charge is applied. It is recommenced, however, to turn the laptop off overnight because of heat harms the battery."

The problem, according to this, is that lithium ion batteries wear out quicker when they are fully charged and exposed to high heat, such as in the case where you use the laptop with a fully charged battery and the AC plugged in.
However, removing the battery may allow dust and dirt into the battery compartment, so you may want to consider that as well.

[sillydog701]

Beside the lifetime of the battery, there's also another issue.

Someone reported that his 12" PowerBook has developed a very noticeable warping at rare of the PowerBook (fan near the power plug). His conclusion was due to the AC power connection... too much heat at that end.

[hillcrest]

My battery(1.25GHZ-15") recharges when it gets below ~ 94%. even when constantly plugged in to an outlet, the battery power will slowly diminish till ~94%, then recharge. I have read that the battery life is proportional to recharge cycles. I let it fully drain every 2-3 wks.

[Michel_80]

Get your facts people! It is BETTER to take out the battery if you are running on AC power. Fact.
When plugged in, you are storing your battery at 100% which is bad, meaning you loose 30% of capacity in no time.

[Musti]

If you will *never ever* use your PowerBook mobile, it is advisable to take out the battery. However, doing so will revert to "Reduced Performance" in Energy Saving preferences.

[hillcrest]

Originally posted by Michel_80:
Get your facts people! It is BETTER to take out the battery if you are running on AC power. Fact.
When plugged in, you are storing your battery at 100% which is bad, meaning you loose 30% of capacity in no time.

So take the battery out and store it when it is dead?

[madmacgames]

I unplug my 12" powerbook when I put it asleep. Not because I worry about the battery but because if the battery if full, the powerbook is asleep, and the AC plugged in, there is a horrible high pitched squealing/squelching noise, that seems to omit from both the power brick and powerbook.

It doesn't do it when awake or while asleep if the battery needs charged. And does not do it if the powerbook is turned off.

[madmacgames]

Originally posted by hillcrest:

Originally posted by Michel_80:
Get your facts people! It is BETTER to take out the battery if you are running on AC power. Fact.
When plugged in, you are storing your battery at 100% which is bad, meaning you loose 30% of capacity in no time.

So take the battery out and store it when it is dead?

lol... yeah... before I hit the road next time I will be sure to drain all of my backup batteries so I can properly store them.

[Michel_80]

Huh? If you are using backup batteries offcourse you have to keep them charged up.
But if you are using your laptop plugged in all the time then take out the battery and store it at 40%. Do not store it at 0%, that is very bad.

[superfula]

Originally posted by Michel_80:
Get your facts people! It is BETTER to take out the battery if you are running on AC power. Fact.
When plugged in, you are storing your battery at 100% which is bad, meaning you loose 30% of capacity in no time.

Ah, no. Lithium Ion batteries lose their charge over time no matter what your usage. Storing them at 100% definately doesn't harm them more than normal. This is pretty common knowledge.

[rag on a muffin]

wow, so many opinions. i was taught that the lithium ions explode if you charge them more than their maximum capacity, or if you discharge them all the way that they will stop functioning, which is why the message says "you are now running on reserve power". it is smart to put your computer to sleep when this happens, especially if its gunna be a while till you get a chance to plug it in.

i would like to give a small tutorial on batteries starting from the beginning of batteries in macs:

lead acid- these things had a bad size+weight to capacity ratio, and had a memory*.

nickel cadmium- these had a better size+weight to capacity ratio than lead acid, but still had a memory.

nickel metal hydride- the nickel cadmium successor. has about the same size+weight to capacity ratio as the nickel cadmium, but no memory.

lithium ion- these have the highest size+weight to capacity ratio of these 4, which is why apple uses these in their current gen powerbooks.

*a memory is when if you discharge it halfway a few times, it will only charge up to that point. i had a powerbook 520c that i bought on ebay, and its battery life was 10 seconds literally. this was probably caused by unplugging the plug for short periods of time, or only having it on in sleep mode. he listed it as a broken battery, but i fixed it with a battery recondition, which i can list how to do if anyone is having trouble with a memory bearing battery.

[Michel_80]

Originally posted by superfula:
Ah, no. Lithium Ion batteries lose their charge over time no matter what your usage. Storing them at 100% definately doesn't harm them more than normal. This is pretty common knowledge.

Common knowledge
Storing them at 100% will loose 30% in a year. Storing them at 40% will loose about 5%. Google it to your content.

" Keep the lithium-ion battery cool. Avoid a hot car. For prolonged storage, keep the battery at a 40% charge level"

[Dr.Michael]

Originally posted by fuddman:
Hi, just a quick question, is it better the actually take the battery out of my Al'15 1.25 if I leave the AC plugged in day and night? I kinda feel that my battery life is shorter now... thanks for your help.

- fuddman

I tested this with my TiBook: I took out the fully charged battery and stored it in a drawer whenever I did not need battery power. Recharged every few weeks, so that charge never dropped below 30 %.
Result: After 3 years the battery still had 90% of its initial capacity and ran the TiBook for more than 4 hours.

Why this is so? The heat makes the internal contacts corrode and this reduces the capacity of the battery. So storing the battery externally is recommended.

With my 12 inch Albook I cannot do this (for obvious reasons). After 7 months the capacity has already dropped below 90% of the initial value. I did not run the powerbook more on battery than my old Ti. And, like everybody knows, the Albook gets very warm (also rev. b).

So I can support from experience what other posters read in the net: Store your battery outside, recharge if the charge drops below 30%. This will enhance the lifetime of your battery.

Michael

[vexingv]

i'm having the same dilemna with my new 12" PB. i dont plan on taking it out much and will only use it around the apartment. some people are suggesting that it is better to take the battery out if only the AC is used. it sort of makes sense just logically thinking about it...

but the real question is, if you take the battery out (like some of you are) do you use something to cover it (does anyone make such a thing?)?

[sillydog701]

This thread is really confusing...
With PC laptops, many people do take out their batteries, but I don't do that with my Dell laptop. And after 3 years of using that Dell laptop, the batteries is still very good.
I remember one of the BIOS updates stated that the better battery management was implemented to prolong the battery life.

Now, with PowerBook 12 (RevC) I have. I don't plan to take out the battery all the time, but I might buy a second battery in few months time when I need to carry it around.

[flypenfly]

http://www.laptopbattery.net/noteboo...ries_life.html

[superfula]

Originally posted by flypenfly:
http://www.laptopbattery.net/noteboo...ries_life.html

Thank you! This is common knowledge. I can't believe there are some out there that think otherwise anymore. Not having much knowledge is one thing, but having the wrong knowledge is quite rediculous. Lith Ion batteries have been around a long time. Some just need to stop believing all the fud they hear from any Joe.

[angelmb]

Thanks all you for the input, so I must take my Al battery out and keep it as cool as I can, due to:

- I have the Al plugged and
- it is plugged to an UPS device

Thanks again.

[SplijinX]

Do they sell covers for the battery compartment? Since I have a 12" PB and the battery is at one of the corners, you can't take the battery out and not have it wobble around if you type on it or use something like an iCurve. Any suggestions?

[rjenkinson]

Originally posted by flypenfly:
http://www.laptopbattery.net/noteboo...ries_life.html

how is it that someone who can write the sentence "Lithium ion notebook batteries normally offer 600 to 800 charge/discharge cycles over 1� to 3 years of useful life..." can't spell the word "lose" properly?

-r.

[Michel_80]

Re Dell, they have advanced batteries which discharge themselves and them charge back up. Weird.

[flypenfly]

Woah, now check this out:

http://episteme.arstechnica.com/eve/...m=134009054631

Specifically:

on't bother. Whoever wrote that is making a common mistake, that of assuming that ANY discharge/charge cycle is the same as any other.

> Lithium ion notebook batteries normally offer 600 to 800
> charge/discharge cycles over 1� to 3 years of useful life.

See, that's only true for full cycles. As the depth of discharge gets shallower, the number gets bigger. If you're talking about recharging it after it loses only a few percent of charge, you could do that for years, long enough that the battery's natural "age death" will happen long before you "use up the cycles."

Some Dell laptops actually deliberately discharge the battery slightly, rather than allowing self-discharge to do the job, before "topping it off." A battery engineer (not from Dell) on the floor at WinHEC a few weeks ago told me that this actually improves the battery's lifetime over either sitting on a shelf at 40-60% charge (recommended storage conditions for Li-Ion) or relying on self-discharge; but that self-discharge and then recharge is still better than storage. The layman's explanation is that letting the battery sit for a long time unused allows it to "stagnate," while putting it through very shallow cycles keeps it more "limber." Or something.

(Really, the longer the ions sit in the "charged" state, the more likely they are to self-discharge in such a way that you can't charge them again.)

> Try to avoid running your laptop battery all the way to zero

Yet more disinformation. Laptops won't LET you run the battery "all the way to zero." "Zero" on the power meter does not mean "zero" to the battery - "zero" on the power meter is simply the point at which further discharge will significantly hurt the battery's life.

That said, shallower discharges than that ARE better, but there's no need to get paranoid about it.

I've run a total of about thirty Li-Ion batteries through my various laptops over the years, enough to be a statistically valid sample; I've tried treating them all kinds of different ways; I've also done a lot of research. My conclusion: The occasional defective sample aside, a Li-ion battery will reach its "chemical death" somewhere between one and three years from purchase, and it won't much matter WHAT you do to it in the meantime: Shallow discharges, deep discharges, store when not using or not.

In fact, I've had pairs of batteries that I bought at the same time, treated nearly identically, and had one die long before the other - it seems that sample variations swamp the effects of different "treatment."

Anyway, life's too short to worry about taking the damn battery out, worrying about whether I put it in soon enough to charge it before the trip, etc., etc. Just one more thing to "manage." LATER with that crap.

[SEkker]

I have to say, the Li battery is one of the few parts of a notebook computer that can be readily replaced when defective. If I had to remove my battery everytime I was charged and plugged in, I'd have ~1000+ battery installs! Sure to damage my machine's outer hardware. Repairing THAT will be MUCH more expensive than any new battery!

[Dr.Michael]

Originally posted by flypenfly:

Anyway, life's too short to worry about taking the damn battery out, worrying about whether I put it in soon enough to charge it before the trip, etc., etc. Just one more thing to "manage." LATER with that crap.

exactly!

[Rainy Day]

Originally posted by SEkker:
I have to say, the Li battery is one of the few parts of a notebook computer that can be readily replaced when defective. If I had to remove my battery everytime I was charged and plugged in, I'd have ~1000+ battery installs! Sure to damage my machine's outer hardware. Repairing THAT will be MUCH more expensive than any new battery!

Not to mention wear and tear on the contacts!

All the advice about taking batteries out of a PowerBook when fully charged is bunk. The original li-ion battery in my Wallstreet recently died... after 6 years of good service! Always left it in the book, and usually had it plugged into A/C most of the time. And this book is still my primary computer and used daily. A friend of mine with a Wallstreet the same age and similar usage habits also squeezed 6 years out of her battery.

[vmarks]

Once a month I run it down until it warns of low battery and falls asleep. This is both the recommended apple advice (among the many different pieces of advice you may see them give) and it's decent to at least exercise the battery once in a while.

That, and it fits with my habits. Do that which fits with your habits, eke as much as you can from the battery, and accept that they don't last forever.

[Simon]

Originally posted by vmarks:
Once a month I run it down until it warns of low battery and falls asleep. This is both the recommended apple advice (among the many different pieces of advice you may see them give) and it's decent to at least exercise the battery once in a while.

It's recommended to do that once a month? Never heard that. I know it's recommended to calibrate a new battery and it's recommended to do it when you have problems with power management or inaccurate battery time estimates, but doing it on a monthly basis? Seems a tad exaggerated to me. Do you have a URL? I'd be interested.

[ashtoash]

Seriously who has so much free time? Do this:

Abuse the battery, plug it in, plug it out. Whatever is fits into your lifestyle. Stop worrying so damn much. When you become obsessed with these little things you become a servant to your computer. You are the computer's MASTER and it shouldn't be the other way around. A computer was designed to make your life easier, NOT steal more of your time.

Best advice:
Stick $8 every month in a jar somewhere. When you have enough money then it's time for a new battery.

Use the saved time to go OUTSIDE into a place called reality.

[Dougmc]

Unless I've missed it somewhere in this thread, one of the best reasons to leave your battery in the PowerBook while plugged in is in the event of a power outage (which seems to occur in my office monthly for only seconds at a time) the computer continues operating as if nothing ever happened. While all the other machines (that aren't running on a UPS) are all restarting themselves.

I just replaced the battery last night in my 17" rev. A PowerBook. I can't accurately quote how much of its life had diminished over the time I've had it, but it certainly wasn't performing as long as I needed it to.

I feel that I got the life out of it that I would have expected.

And, when I replaced the battery, it was the first time I had taken it out myself.

[macintologist]

Originally posted by ashtoash:
Seriously who has so much free time? Do this:

Abuse the battery, plug it in, plug it out. Whatever is fits into your lifestyle. Stop worrying so damn much. When you become obsessed with these little things you become a servant to your computer. You are the computer's MASTER and it shouldn't be the other way around. A computer was designed to make your life easier, NOT steal more of your time.

Best advice:
Stick $8 every month in a jar somewhere. When you have enough money then it's time for a new battery.

Use the saved time to go OUTSIDE into a place called reality.

[iomatic]

No doubt.

I can't believe I wasted 2 minutes reading this thread. As paraphrased before:

screw it
just use it

Originally posted by macintologist:

...

...

[Dr.Michael]

Originally posted by Dougmc:
...is in the event of a power outage (which seems to occur in my office monthly for only seconds at a time)...

Are the states a third world country?
The last power outage that I remember was during a blizzard when I was 10 (30 years ago)

[Simon]

Originally posted by Dr.Michael:
Are the states a third world country?

When it comes to electrical power: Yes.

In the past ten years I've been in Europe, I've seen one power cut during a blizzard. In California we had power cuts about once every other month. But then again, in central Europe most power lines are well protected underground and regularly maintained.

I have no idea why my fellow American citizens put up with this kind of crappy power supply you'd only expect in communist countries. Probably because people prefer to buy $200 UPS devices and pay half a cent less per kWh.

[Guy Kuo]

The Cadex battery article tends to suggest that deep discharge cycling of Lithium ion batteries reduces total capacity much more rapidly than shallow discharges. On the other hand, deep discharge is needed on occasion to resynchronize the battery charge monitoring system.

The temperature of the battery in my plugged in 12 inch PB is currently 36 C - cooler than body temperature and much cooler than a hot car in the sun. I don't think that would qualify as keeping the battery in a hot environment.

I've always kept my batteries in laptop when plugged in. Battery life in my iBooks and Powerbooks is down about 30% after two years. Not actually bad for a limited life item.

More importantly, safeguarding my work is worth much more to me than the relatively low cost of a new battery every two years. Without a battery in place, a brief power outage could be a disaster. With a battery in place, the laptop has it's own uninterruptible power supply.

I think keeping the battery outside the machine for a debatable "improvement" in battery life is a false economy for anyone who uses their PB for serious or important work.

[shabbasuraj]

Use it like it was meant to be used. Period.

By the time my Rev.C PB needs a new battery (i.e. gets less than 10 minutes of battery life) I will already be lusting over a Rev.D G5 PB that is 0.5 inches thick, with 4 GB of RAM, SuperSonic Green Ray DVD Drive, Built in 802.11Z, 1600x1200 TFT, with a 10 hour battery life.

Thanks Apple Marketing Team.

(just kiddin')

[Dr.Michael]

Originally posted by Simon:

In the past ten years I've been in Europe...

Hi Simon,

I have just checked your profile after I saw the cited remark and found out that you are a research physicist (like me).

Interesting to see that also other physicists use Macs. At my institute (Max-Planck) I am one of very few Mac users. Most of my colleagues use cheap dell linux boxes.

Whats your field of research and where have you been in europe?

[Simon]

Originally posted by Dr.Michael:
Interesting to see that also other physicists use Macs. At my institute (Max-Planck) I am one of very few Mac users. Most of my colleagues use cheap dell linux boxes.

Many of my colleagues as well. But PowerBooks are getting more and more popular. Especially since the expensive Compaq notebooks the lab mostly bought can't run Scientific Linux very well (power management, wirless LAN, etc.).

OS X is a godsend in physics. It gives us all the UNIX goodies we'd like (damn, I can even use my Tcl/Tk interfaces I wrote for Linux on my Mac), but at the same time we can deal with physics instead of with kernel issues (Linux) or incompatibilities/security (Windows). The platform gives us great flexibility. While some of my colleagues have as many as five different systems in their offices, I am hardly using anything else than my Mac.

Our lab has about a 1000 employees of which maybe 30% use OS X (mainly expermenters), 30% use Linux and 40% use Windows (mainly secretaries and technicians). There's a group of about a dozen full-time Windows supporters. Linux support is done by two guys (of which one is also the Lab's IT security guy) and Mac support is done by one guy in his spare time (he's a normal physicist and not paid to do support). I think that already says quite a lot.

Whats your field of research and where have you been in europe?

I work in accelerator physics (beam dynamics and computational stuff). In Europe I've been in Switzerland, France, Italy, Scandinavia and Germany. And I've seen more than enough of England in the five days I spent there.

Wow, that was completely OT.


Back on topic, the Li ion battery I had in my 12" PowerBook lost half its capacity within 12 months of use. Recalibrating and resetting the PMU didn't change anything. I just recently received a new battery. I don't know if that can be considered normal. I'd prefer a battery to keep its full capacity for at least 2 years (my normal upgrade period). My PowerBook is plugged in most of the time (at the office and at home) and I only use it on battery when I'm traveling.

[Dr.Michael]

Originally posted by Simon:

OS X is a godsend in physics.

Thats exactly what I think.
Thanks for your info.

And sorry fuddman for the digression.