Battery life charging protocol -- what to do?

[chris123]

Hi All,

I'm new to the Thinkpad family having just received my T60 a week ago. I haven't had a ton of free time to really get into it yet, but hopefully I will soon enough.

I wanted to ask a question about how to use the battery. I've read many different "tips" but some seem to be contradictory. One site mentioned the importance of completely draining the battery the first time out, then only discharge it about half way for every time thereafter. Another site said that Li-Ion batteries don't have memory so you can discharge it any way you like.

And how long can you keep the battery in the computer when you're plugged in? Since heat is the enemy of long battery life, then should you take the battery out if you're working off AC power for a significant stretch of time?

Any tips greatly appreciated.

[chris123]

No replies yet.

I found this on metafilter. It cites Thinkwiki and notes some potential pitfalls of following their advice. They do suggest taking the battery out when running AC.

"I use my Thinkpad T40 about 99% of the time on AC, and leave it on and running 99% of the time. My main 9-cell extended battery's capacity has dropped to 50% of its design capacity over the course of a year. I also have a secondary Ultrabay battery, It has dropped to about 60% of its design capacity over about 9 months. Thinkwiki's page on battery treatment has some advice that seems difficult to follow:

* remove the battery when running on AC
* avoid charging the battery if nearly full
* never store the battery fully charged (40% is ideal)

This makes it awfully difficult to take off with a fully charged battery at a moment's notice. What I'd have to do is unplug, let it drop to about 40%, plug-in, remove the batteries, and set them aside (in the fridge). Then, if I need to take the laptop some place to run on battery, pull them out of the fridge, put them in, and let them charge up before I take off. How annoying, and definitely doesn't seem to be particularly geared toward the on-AC-most-of-the-time usage scenario."

Here is what Thinkwiki says in full:

* avoid deep discharges except when resetting fuel gague or reconditioning a battery; partial dis-/recharges are better for the battery lifetime (note: fuel gauge will slowly get inaccurate over time)
* remove battery when on AC (due to heat)
* avoid exposing the battery (or notebook) to excessive heat
* avoid deep discharges except when resetting fuel gague or reconditioning a battery; partial dis-/recharges are better for the battery lifetime (note: fuel gauge will slowly get inaccurate over time)
* remove battery when on AC (due to heat)
* avoid exposing the battery (or notebook) to excessive heat
* never fully charged or discharged, ideally at about 40%
* cool and dry, but do not freeze them. 10-15C is recommended



More info here from Tom's hardware:


http://www.geardigest.com/2006/11/02/ho ... y_blow_up/

[wallybear]

A battery is a consumable item...it has a finite lifespan. Each discharge/charge cycle will "consume" some of the "life" in the chemicals that make up the battery.

While I agree that some of these tips might help to lengthen the useful life of a laptop battery, the issue for me is "by how much and at what cost in terms of time and trouble?"

In my experience, the inconveniences associated with following these tips are greater in consequence than the small (if any noticable) improvement in battery service life attributed to following these tips.

In other words, use your battery as intended....keep it installed and charged so you can use it. One caveat: set the Power Manager software to its setting that will lengthen service life by not charging the battery to 100% all the time. This will help to lengthen service life.

Instead of being compulsive about ways to improve battery life at the expense of convenience, I suggest you work on saving some money to buy a new one when it's needed. The average life of a laptop battery is about 18-24 months. That's by design and the facts of physics (chemistry).

A new T60 6-cell battery costs about $150. That's about $100 more than it should cost (profit margin to be considered) but it's part of the cost of ownership of a laptop. Why do you think they are warranted for only 1 year? (They aren't expected to last 2 years.)

[kkposh]

my classmate's 9 cell battery has only been charged for 5 times during the past 6 months since he got his laptop and now has dropped to 60% of its origin designed capacity

however,my 6 cell battery is still in good condition after 2 months use and has been charged for 20 times

In my opinion,you should get your battery discharged to about 5% at least one time every month.
Always full charged or always not using it does no good to your battery.


sorry for my bad English expressions,but hope this will help you

[pharao111]

A battery is a consumable item...it has a finite lifespan. Each discharge/charge cycle will "consume" some of the "life" in the chemicals that make up the battery.

While I agree that some of these tips might help to lengthen the useful life of a laptop battery, the issue for me is "by how much and at what cost in terms of time and trouble?"

In my experience, the inconveniences associated with following these tips are greater in consequence than the small (if any noticable) improvement in battery service life attributed to following these tips.

In other words, use your battery as intended....keep it installed and charged so you can use it. One caveat: set the Power Manager software to its setting that will lengthen service life by not charging the battery to 100% all the time. This will help to lengthen service life.

Instead of being compulsive about ways to improve battery life at the expense of convenience, I suggest you work on saving some money to buy a new one when it's needed. The average life of a laptop battery is about 18-24 months. That's by design and the facts of physics (chemistry).

A new T60 6-cell battery costs about $150. That's about $100 more than it should cost (profit margin to be considered) but it's part of the cost of ownership of a laptop. Why do you think they are warranted for only 1 year? (They aren't expected to last 2 years.)

yap he's right... i'm using my t60 with the 9cell battery now since august 06 and i'm using it both ways with plug and battery inside and without plug like every day but mostly when i'm in the library doing studies i'm in the first told mode... so don't worry about the battery and like my fellow t60 owner just said... you paid almost 2000$ for your piece of hightec so don't have to worry about 150$ for a new battery in two years bcs its the money worth... and to calm you down (probably it'll help) i used my powerbook for four year and the battery was in 95% condition after that period even thought i used it a lot of times on the plug..i think the new batteries are well developped nowdays so that you don't have to worry about that topic anymore...

[chris123]

A battery is a consumable item...it has a finite lifespan. Each discharge/charge cycle will "consume" some of the "life" in the chemicals that make up the battery.

While I agree that some of these tips might help to lengthen the useful life of a laptop battery, the issue for me is "by how much and at what cost in terms of time and trouble?"

In my experience, the inconveniences associated with following these tips are greater in consequence than the small (if any noticable) improvement in battery service life attributed to following these tips.

In other words, use your battery as intended....keep it installed and charged so you can use it. One caveat: set the Power Manager software to its setting that will lengthen service life by not charging the battery to 100% all the time. This will help to lengthen service life.

Instead of being compulsive about ways to improve battery life at the expense of convenience, I suggest you work on saving some money to buy a new one when it's needed. The average life of a laptop battery is about 18-24 months. That's by design and the facts of physics (chemistry).

A new T60 6-cell battery costs about $150. That's about $100 more than it should cost (profit margin to be considered) but it's part of the cost of ownership of a laptop. Why do you think they are warranted for only 1 year? (They aren't expected to last 2 years.)

Thanks for your input.

While I agree with your basic point, I think the convenience factor is more important than the cost effectiveness. If the battery starts to lose its charge quickly due to suboptimal usage, then you can't get 4 hrs out of it. Pretty soon it's 3hrs, then 2hrs. Who wants to lug around a second battery?

My idea here is to discover ways to prolong the 4hr+ battery life for as long as possible.

If it only takes a couple of tips to achieve this, then I'll do it. Based on the Thinkwiki site, it seems that removing the battery when using AC power is probably the single most important thing one can do to this end.

[gator]

I have had my T60 since last august, and always have used the battery stashed in my T60. The battery capacity has reduced probably by 1.5%, which is very very normal. I usually set the charge thresholds between 40-70% and unplug the machine when I switch it off. The returns for storing the battery out of the machine are too little for me to go through the pain of taking it out of storage evertime I want to go out.

In my experience, Thinkpad batteries are much better than other OEM batteries. Whether you use it or not, it is going to start deteriorating after 2 years. Atleast use it when you want to - after all, it is a consumable!

[whizkid]

As another data point: I received my T60 in December, and have used it nearly every day, usually unplugged. I have a 9-cell and an Ultrabay Slim battery installed.

I'll guess I have over 50 charges on the main battery (I'm running Linux right now, and don't know how to get the charge count), but the last charge was to 90% of design capacity, which is pretty good.

My bay battery, which is newer and has fewer charges, has only 60% capacity remaining.

[wallybear]

In response to your comment that your wish is to "discover ways to prolong the 4hr+ battery life" of a new battery I have to say this: that's just not possible given the physics and chemistry of a lithium-ion battery. I wish that it were, my friend, but it is not. While you might slow down the rate of deterioration to some degree (perhaps measurable, perhaps not) you can not preserve the battery's original maximum capacity. No way, no how.

The idea that some simple "usage tip" can change the laws of physics reminds me of the cheap automobile "gasoline boosters" that used to be sold on late-night TV with the promise of doubling gas mileage (and at only $39.95 plus shipping and handling!).

As I explained in my last post, each discharge/charge cycle "uses up" some of the capacity of the battery's supply of chemicals. And while "battery-conservation efforts" such as ensuring slow charging rates or maintaining ideal temperatures might theoretically or even practically "slow down" the deterioration rate of a battery (albeit slightly) the real determining factor is the physical change that takes place in the chemicals in the battery. And, to be honest, most people don't want to constantly remove batteries, cool them, etc. with the hope of prolonging battery life. They just adapt to the fact that batteries are a consumable product (sort of like milk...when you drink the last milk in the carton you have to go buy more).

So, with due respect for your stated goal ("discover ways to prolong the 4hr+ battery life") I respectfully suggest that you try to adapt your thinking to match the facts: a battery can not be made to retain its original maximum capacity over its life-cycle by following some "usage tips". No matter what we think or desire it's the chemistry of the battery that determines its capacity at any given time. And its the charging, discharging, recharging, etc., etc. cycle that uses up those chemicals.

Oh, and in answer to your rhetorical question, no one "wants to lug around a second battery" but due to the facts of physics we have to. I still have a 600X ThinkPad which was notorious for short battery life (I have to keep two on hand in order to use it for more than an hour on battery). I wish it had the battery usage profile of my T60 but it doesn't. Time and progress have marched on in the 7 years since it was built. But I still use the computer and I have resisted buying a new $100 battery (aftermarket only now) because I am trying to get the most "milk" out of the two batteries I do have.

I hope you find this posting helpful and supportive of your original inquiry. That's the spirit in which it was intended and offered.

[chris123]

At the risk of sounding naive, I doubt that the Thinkwiki site would have bothered to post the guidelines if they had little or no measurable effect.

Wallybear -- you seem convinced that's it not worth it. Where's your data? You don't seem to refer to any and yet you're already made up your mind.

I think the question can only be resolved through reliable data.

Clearly, I wouldn't bother with any of this stuff if the difference was negligible. But from what I've read, it's not negligible.

Have a good weekend.

[chris123]

I have had my T60 since last august, and always have used the battery stashed in my T60. The battery capacity has reduced probably by 1.5%, which is very very normal. I usually set the charge thresholds between 40-70% and unplug the machine when I switch it off. The returns for storing the battery out of the machine are too little for me to go through the pain of taking it out of storage evertime I want to go out.

In my experience, Thinkpad batteries are much better than other OEM batteries. Whether you use it or not, it is going to start deteriorating after 2 years. Atleast use it when you want to - after all, it is a consumable!

Thanks. Yeah - 1.5% is tiny. But you do unplug it when not in use. That's helpful.

[Giovanni]

chris-

While I have not had my T60p long enough to measure battery life, my dad's office has been providing Thinkpads to its employees for quite a while, so he and his colleagues have had to go through many batteries over the years.

From his experience, frequent charging seems to prolong battery life. He always charges his battery as often as possible, whereas one of his co-workers drains the battery completely before recharging it. He usually has to send in for a replacement battery some time before my dad does.

As such, I think that "topping off" is a better strategy than deep discharging and recharging, that's probably what I'm going to do. As for unplugging the battery when the machine is on AC power, I think that's going a bit too far and not really worth the trouble.

Hope this adds something to your strategy.

[hoplite]

From what I've read this is what I've found out about Li batteries:

- Li batteries start losing max capacity as soon as they are produced. They lose capacity no matter what. The only thing you can affect is how fast they lose that capacity.

- Heat will cause the Li battery to lose max capacity faster.

- Keeping the battery fully charged will cause the battery to lose max capacity faster.

- There is no real benefit to completely draining the battery and recharging it to restore 'memory'. However, it is good to drain the battery and recharge it to reset the battery meter.

I generally keep my battery in the 70-80% charge range and I'm almost always on AC power. If I know I'm going to need it I'll fully charge my battery before a day of travel etc.

It's probably not the optimal method to prolong battery life but it strikes a good balance between convienence and making some effort to prolong the battery.

[Giovanni]

- There is no real benefit to completely draining the battery and recharging it to restore 'memory'. However, it is good to drain the battery and recharge it to reset the battery meter.

I believe memory problems only apply to NiCd and possibly NiMH batteries, Li-ion batteries do not require full discharge cycles to prevent diminished capacity.

After some more consulation with my friend Wikipedia, here's some of their info on prolonging the life of Li-ion batteries:

* Unlike Ni-Cd batteries, lithium-ion batteries should be charged early and often. However, if they are not used for a longer time, they should be brought to a charge level of around 40%. Lithium-ion batteries should never be "deep-cycled" like Ni-Cd batteries.
* Li-ion batteries should be kept cool. Ideally they are stored in a refrigerator. Aging will take its toll much faster at high temperatures. The high temperatures found in cars cause lithium-ion batteries to degrade rapidly.
* Lithium-ion batteries should never be depleted to empty (0%).
* According to one book, lithium ion batteries should not be frozen (should not be stored under -40 °C), because most lithium-ion battery electrolytes freeze at approximately −40 °C (this is much colder than the lowest temperature reached by household freezers, however).
* Li-ion batteries should be bought only when needed, because the aging process begins as soon as the battery is manufactured.
* When using a notebook computer running from fixed line power over extended periods, the battery can be removed and stored in a cool place so that it is not affected by the heat produced by the computer.

Wiki pages on battery types:

http://en.wikipedia.org/wiki/Ni-cad
http://en.wikipedia.org/wiki/NiMH
http://en.wikipedia.org/wiki/Lithium_ion

Hope this is of use.

[chris123]

Thanks for Giovanni and Hoplite for their helpful suggestions.

I think frequent charges are the way to go.

It will be a hassle to take out the battery when it's on AC power, but I'm on AC 95% of the time in my current situation so I'll give that a shot.

[pae77]

. . . It will be a hassle to take out the battery when it's on AC power, but I'm on AC 95% of the time in my current situation so I'll give that a shot.

Not worth it and, on some models (not sure about T60) will prevent CPU from running at full power.

[wallybear]

At the risk of sounding naive, I doubt that the Thinkwiki site would have bothered to post the guidelines if they had little or no measurable effect.

Wallybear -- you seem convinced that's it not worth it. Where's your data? You don't seem to refer to any and yet you're already made up your mind.

I think the question can only be resolved through reliable data.

Clearly, I wouldn't bother with any of this stuff if the difference was negligible. But from what I've read, it's not negligible.

Have a good weekend.

Well, here's my reasoning for having "made up my mind" stated in more basic terms....

I don't need to prove--with empirical data--that small improvements in battery life (that is, the number of months a battery can supply a useful charge) to have accepted the fact that all batteries have a finite lifespan. They are consumable items. Like gasoline in a car....you may save a little by careful driving but the number of variables involved in gathering useful empirical data makes the effort to collect such data a rather compulsive activity (sort of what the EPA or the folks at Consumer Reports do for a living). In other words, I already know that batteries don't last forever (I've used many over the past 18 years since I got my first laptop). I already know from personal experience (which is good enough for me) that removing the battery when I'm plugged into A/C or docked or storing the battery in the refridgerator when it's not being used, etc., etc., are TOO INCONVENIENT for ME in relation to the modest (even if they were measurable) gains that I might achieve. I think most everyone can relate to the experience of wanting the "newness" of a machine (and its battery in this case) to last longer or forever. And, most may have tried ways (antecdotal or even quasi-empirical) to make that happen. So, I empathsize. In responding to your posts I was hoping to add to your knowledge by providing facts which you may not have considered.

Oh, I guess that wasn't stated in very basic terms after all. <grin>

So, now that I know what you're asking for (empirical proof of modest gains) I will stop posting replies. Perhaps someone here can give you that data. Meanwhile, I'll go back to using my computer as it was meant to be used (or at least how I want to use it) and when I need a new battery I will buy one.

I don't suppose that it would help here if I repeated my point from a previous posting that there is NO WAY to make any battery retain its original capacity (that is, keep it at 3 or 4 hours running time during its useful life). The physics and chemistry explanation I gave before is the reason: the batteries we have now (Li-On) will slowly degrade in run time over their lifespans. That is their nature (sort of the same as the nature of human beings is to grow older and slower over time). So, even if you succeed in SLOWING down this degrading process (which is what I now understand you seek to do and to prove with some empirical test) you will still have a battery that when new ran for 4 hours and a year later runs for 2 hours (for example, and all things being equal).

I know that the previous paragraph repeats a point I've made before....but I'm offering it again because those are the FACTS that have allowed me to "make up my mind" about how I approach the use of my T60 and its battery.

I'll watch this thread to see if you get anyone offering you the empirical data you need to fulfill your quest. Good luck.

[pappcam]

People actually take out the battery on their laptops when they're plugged in because they think it's better for the battery?

Do these people also turn their car off at every red light so they save fuel?

How about turning the TV off everytime you leave the room?

Seems rather silly and pointless to me.

[chris123]

I was just talking to a friend who's a tech person for IBM who has a T42. He said he runs the battery down as close to zero as possible before recharging it. Pretty weird, given that there seems to be a lot of people -- apparently persuasive -- who say to specifically avoid doing this to any Li-Ion batteries.

This is what I'm talking about -- all the conflicting views out there on this question.

[Talon88]

:::

Sorry wallybear, I don't buy what you said!
If you take good care of your battary, it can last
longer with long run time! Nothing better than a prove.....!
This is the status of my 1.5 years Old Batt.

Click Image to Enlarge!


:::

[ahe]

If you take good care of your battary, it can last
longer with long run time! Nothing better than a prove.....!

What did you do to take care of it?

[hoplite]

[quote=wallybear]I'll watch this thread to see if you get anyone offering you the empirical data you need to fulfill your quest. Good luck.[/quote]

Somebody actually posted this link before. I'm not sure what you consider modest gains but obviously taking steps to prolong battery life has a significant impact.

You're correct that Li batteries do degrade and they have a finite lifespan as do people in your analogy... But that still doesn't mean you should eat a bacon sandwich everyday.

Permanent Capacity Loss versus Storage Conditions Storage

Temperature 40% Charge 100% Charge
0 °C (32 °F) 2% loss after 1 year 6% loss after 1 year
25 °C (77 °F) 4% loss after 1 year 20% loss after 1 year
40 °C (104 °F) 15% loss after 1 year 35% loss after 1 year
60 °C (140 °F) 25% loss after 1 year 40% loss after 3 months
Source: BatteryUniversity.com[6]

H

[TPA]

I am typing this on my X30. The battery on this machine has a manufacture date of august 2002 (almost 5 years old). it is a Li-ion type.

its design capacity is 47.52 Wh
its full charge capacity is 37.07 Wh

I never paid any attention to charge and discharge levels, never removed it while on ac, basically just did whatever....

looks like it has about 75% of its capacity left after all that abuse and 5 years of time.

[Giovanni]

Do these people also turn their car off at every red light so they save fuel?

Ironically, I actually heard this suggested today on the radio because of the ridiculous gas prices. xD I believe they said if you're sitting for longer than 10 seconds to turn off the car.

I was just talking to a friend who's a tech person for IBM who has a T42. He said he runs the battery down as close to zero as possible before recharging it. Pretty weird, given that there seems to be a lot of people -- apparently persuasive -- who say to specifically avoid doing this to any Li-Ion batteries.

Just because someone's in tech support doesn't mean they're terribly smart or knowledgeable in all areas. As I said both my dad and his colleague have radically different charging techniques even though the "topping off" method preserves battery life and is considered to be much healthier for a Li-Ion battery.

Your friend may either consider it too inconvenient to charge frequently, or he may not know that it's the better route to take. Maybe he thinks Li-Ion batteries are the same as NiCd batteries, who knows. He may just not care either way.

There's no real need to be obessive about preserving your battery's life as much as possible, it has been said repeatedly that you can't keep them new forever, only prolong their life.

The best and least inconvenient thing to do I think is just frequent charging, but if you're REALLY serious about it then you should make sure you never drain the battery too low, and every time you use AC power you should put the battery in the refrigerator. That would preserve the battery the most, but you have to sacrifice considerable amounts of convenience to achieve that effect. It all depends if it's worth it to you or not.

[wallybear]

Somebody actually posted this link before. I'm not sure what you consider modest gains but obviously taking steps to prolong battery life has a significant impact.

You're correct that Li batteries do degrade and they have a finite lifespan as do people in your analogy... But that still doesn't mean you should eat a bacon sandwich everyday.

Permanent Capacity Loss versus Storage Conditions Storage

Temperature 40% Charge 100% Charge
0 °C (32 °F) 2% loss after 1 year 6% loss after 1 year
25 °C (77 °F) 4% loss after 1 year 20% loss after 1 year
40 °C (104 °F) 15% loss after 1 year 35% loss after 1 year
60 °C (140 °F) 25% loss after 1 year 40% loss after 3 months
Source: BatteryUniversity.com[6]

H

Wow. This appears to be an emotionally-charged issue for some folks...as well as one with plenty of room for what I call "the Enzyte Effect" (more commonly known as the Placebo Effect).

And, ironically Hoplite, the data you've listed (Battery Capacity Loss vs. Storage Temperature) actually PROVES many of my previous statements on this thread. So thank you for providing it.

For those reading here who may not have been listening (or who want my thesis stated very simply) here it is again:

Use your laptop battery as it was intended to be used: charge it when it gets low (and don't overcharge it) AND be prepared to eventually replace it because it has a finite life. If you feel the need to put your battery in the freezer between uses or if you are complusively watching your battery's runtimes between charges then...well, you're probably not interested in what I have just said. So, do what you want, believe whatever you want, and buy Enzyte to be like "Bob" if you want (the envy of his neighbors). Whatever.

But whatever you do---or whatever you think---it doesn't change the fact that batteries are chemical "engines" that are subject to several factors which will inevitably effect their useful lifespans as power sources for laptops.

Yes, sometimes the "your mileage may vary" caveat must be applied here (as in the cases of the "lucky" few who have gotten 5 years of useful life out of a battery). But, the scientific (i.e., empirical) point I have been stressing here is that real data to prove real gains that real people can put into real practice just do not exist or at the least are in very short supply. Batteries don't last forever...voodoo or snake oil or just old-fashioned wishful thinking not withstanding.

End of my friendly contributions to this thread. Bye!

[rukiri]

As someone already noted above, the characteristics of NiCd NiMh and Li-Ion batteries are all different. In my opinion, the varying strategies people use to prolong their battery life is because of this.

For example, the discharge-100% charge technique came from NiCd and NiMh batteries, where it was extremely helpful. Those batteries do have a memory effect, and doing a full discharge/recharge can help the battery "remember" it's full charge.
Li-Ion batteries, however, do not have this memory effect and apparently (I did not know this) doing a full discharge-recharge can actually be harmful for the batteries.

As you are currently experiencing, however, solid consistent information is hard to find on this topic. People remember things from how they used to be, have anecdotal experiences, and share advice they heard from a guy who heard it from another guy, etc.

My best advice, and it isn't very good, is to just go with what wikipedia says, and try to confirm it with your own experiences.

[hoplite]

Wow. This appears to be an emotionally-charged issue for some folks...as well as one with plenty of room for what I call "the Enzyte Effect" (more commonly known as the Placebo Effect).

And, ironically Hoplite, the data you've listed (Battery Capacity Loss vs. Storage Temperature) actually PROVES many of my previous statements on this thread. So thank you for providing it.

For those reading here who may not have been listening (or who want my thesis stated very simply) here it is again:

Use your laptop battery as it was intended to be used: charge it when it gets low (and don't overcharge it) AND be prepared to eventually replace it because it has a finite life. If you feel the need to put your battery in the freezer between uses or if you are complusively watching your battery's runtimes between charges then...well, you're probably not interested in what I have just said. So, do what you want, believe whatever you want, and buy Enzyte to be like "Bob" if you want (the envy of his neighbors). Whatever.

But whatever you do---or whatever you think---it doesn't change the fact that batteries are chemical "engines" that are subject to several factors which will inevitably effect their useful lifespans as power sources for laptops.

Yes, sometimes the "your mileage may vary" caveat must be applied here (as in the cases of the "lucky" few who have gotten 5 years of useful life out of a battery). But, the scientific (i.e., empirical) point I have been stressing here is that real data to prove real gains that real people can put into real practice just do not exist or at the least are in very short supply. Batteries don't last forever...voodoo or snake oil or just old-fashioned wishful thinking not withstanding.

End of my friendly contributions to this thread. Bye!

You asked for empirical evidence that you can take steps to significantly increase your battery life.

Another poster provided the information as a link:
77F /40% Charge /1 year would equal a loss of 4% of the batteries permanent capacity.

77F/100% Charge/1 year would equal a loss of 20% of the batteries permanent capacity.

This data shows that a user can expect significant gains over the usable life of the battery. At year 3 a battery stored at 100% charge will have only 40% of it's total capacity left whereas a battery stored at 40% charge will have 84% of it's charge left.

Again, you asked for empirical evidence so I provided it from the other poster's link. It seems impolitic to get what you ask for and when it doesn't show what you want to accuse other people who are trying to help of attempting to pander "snake oil and vodoo" suggestions.

Cheers.

[wallybear]

I know I said I was through with this thread but I feel the need to clarify my statements and purposes for Hoplite.

1- Please reread this entire thread because I have NOT been asking for empirical evidence to support "steps (you can take) to significantly increase battery life". I have been pointing out that the available reports of such "evidence" are generally NOT scientific (in the sense of them being comprehensive studies with good internal and external validity). And, I've said that those ideas that have been spread by word of mouth are IMPRACTICAL. For example, I don't want to try to maintain a 40% charge in a battery (if that were even possible) in an attempt to reduce the loss of battery life from 20% to 4%. I also don't want to store my battery in the refrigerator or pull it out of my laptop when I'm not using it and I don't want to fret and obsess about it. I will PAY the $150 or so when the time comes. THAT's what I've been saying.

2-My suggestion that "voodoo and snake oil" are involved here has to do with the fact that FACTS sometimes don't reach people who have BELIEFS or EXPECTATIONS that they must fulfill regardless of reality. There are countless examples of people trying to sell things (or ideas or practices) that are assumed or expected or claimed to yield results. Some people who really want to believe or to have "proof" in their hands to support their beliefs don't look beyond the promises to understand the real science behind things. I will admit that I now think that perhaps my tenacity in pressing this point has been misguided (or at least missed its mark). So in substitution for that argument I'll suggest that we consider how much real empirical evidence the world has had with countless millions of laptops and their batteries have been in use in the past 15-odd years. That "experiential evidence" has shown that laptop batteries have a variable life (within a range that depends on various factors) based on their chemical compositions. The fact is, the "real-world" evidence shows that there are NOT "simple usage practices" have a significant and reliable (that is reproducible in a controlled testing sense) effect on battery life. While there are THEORETICAL gains (modest though they might be), they are not PRACTICAL.

3-Finally, I'll point out that the original poster (Chris123) said himself (or herself) that there are "conflicting views out there on this question". I'll say one more time (really, just this once more) that this battery-life debate is a classic example of BELIEF vs. SCIENCE. And, because there are many variables involved (lots of them, actually, including manufacturing variances, cell capacity, chemical purity, etc., etc.) there is the potential for "voodoo and snake oil" promises. It is ironic (to me at least) that the experience gained from millions of real-world tests done every day for years with laptop batteries (I'm talking about all the people who use them) is always disregarded by people who are looking for proof of their beliefs. In other words, if there were PRACTICAL and DEPENDABLE ways to SIGNIFICANTLY extend laptop battery life then surely many people would have mentioned them by now (wouldn't they?)

So, in exasperated finality, I will end with what I've said before:

Use your laptop battery as it was intended to be used: charge it when it gets low (and don't overcharge it) AND be prepared to eventually replace it because it has a finite life. If you feel the need to put your battery in the freezer between uses or if you are compulsively watching your battery's runtimes between charges then...well, you're probably not interested in what I have just said.