Notebook Battery Guide

There is at least one brand that does this. Unfortunately it completely escapes me which one it is. Benq is the only name coming to mind.

And while I understand where you are coming from, I would hate to explain the function to a "normal" user. My wife is a very intelligent person who makes good use of her laptop. There is no way I would want to explain to her why she should do this. It wouldn't help that I don't agree with doing this (see my post yesterday).

Where do you get this info from? To the best of my knowledge, this is already happening. LiIon cells can't be trickle charged (like Lead Acid and NiCad). Doing so is bad - not just in "life" terms but as in "dangerous". All laptops will charge the battery to 100% and then the charging turns off. There is no power being applied to the battery until the next time the the laptop decides the battery needs to be charged. And this will happen when the charge level of the battery drops to a certain point. In the laptops I have used, this is 95%.

If you want to see what I mean, with the battery at 100%, unplug the laptop from AC. Let the charge drop to 96% and plug it in again. The battery will not start charging. Unplug again and let the charge drop to 95%. When you plug in again, the charger will kick in and take the battery up to 100%.

Another thing with this is the battery self-discharge. All batteries loose a charge as they are sitting not being used. LiIon loose the least - less than 5% per month but in the first 24 hours it could be as much as 1%. If you leave your laptop plugged in for a few days starting with a charged battery, you should see that the charge level drops by 1 or 2%. I have to admit to not trying this experiment myself as I rarely go a whole day with the laptop plugged in.

The heating issue for batteries is more about them being heated by other components of the laptop. As many laptops have components that have temperatures over 50C, it is reasonable to think that this heat could affect the battery. But, whenever I have pulled a fully charged battery from a running laptop, they have never felt to be warmer than room temperature.

David

 

Yes, that is the problem for a lot of the advice around for laptop batteries. It was based on the rules for NiCad and then NiMH cells and it is hard to convince people that the rules have changed for LiIon. The guide at the beginning of this thread is a great reference to point to.

That's bad. I have run laptop batteries down to the automatic hibernate point plenty of times without any obvious loss. I have wornout several LiIon batteries with an older laptop. I was frequently taking the battery below 10% on these laptops but never saw a sudden drop in life until the last month or so. Maybe I was lucky.

David

 

So have it by default set to "always charge to full when plugged in." That solves the 'normal user' problem, as they won't even know the option to leave at 40% is there. Simple.

As to the battery being plugged in on AC, thanks, I knew about the self-discharge but always thought that the laptop was constantly charging the battery to 100% and then the battery was powering the laptop. Good thing this isn't the case.

 

To all the last few posts, a couple of comments in no particular order.

As far as trickle charge? Li-Ion do. They will not over charge. As far as rundown? Running down below a certain level will destroy the battery. Therefor it is protected and should not happen because of a circuit on the battery. I believe it is called a smart Li-Ion battery. I am sure much explanation prior.

40% is way over rated. Once again discussion is there in prior posts. If in addition to heat being the enemy cycles are also? Well forget heat. If I have 600 charge cycles that is 600 full discharge full recharge? Well if you keep at 50% and recharge 50% common sense and simple math says you would get 1200 of those half cycles? Other than a minor adjustment for heat these numbers bear out. So I would ask what is gained other than the inconvenience of a half charged battery?

Pretty clear for most people leave battery in and spend $100 to $150 for a new one when it wears out. Nothing lasts forever including your battery?

Consider?

 

My understanding is that continuing to charge LiIon cells once they are fully charged is bad. And hence the chargers don't do this and the protection circuit in the batteries is designed to prevent this as well.

As far as I can tell, most people say "But I never use it and now it doesn't hold charge, what's going on?" Then they come here and complain

In general, I agree with you about the 40% charge. As a day-to-day thing, it is pointless. But, I use the battery most days on my commute. And my general advice to people is to put the battery in the laptop and forget about it. But, if something happened that I knew I was not going to use the laptop for a month or so, I would do the "discharge to 40%, seal it in a bag and store it in the fridge" thing. My opinion is this is a long-term storage thing, not an everyday advice.

Also, you will see me posting about batteries a lot (here and elsewhere). My aim is to make sure everyone is educated enough so they can make their own decisions. And make sure the bad info that was being posted was corrected quickly.

David

 

Ok, I'm slightly confused, it seems from reading through this thread that it is not a good idea to run your battery down to zero. But I just read through the manual for my new laptop and in there it suggests that I do just that by starting the BIOS and leaving the computer on till the battery runs out.

Here is a link to the manual, the relevent bit is on page 11(takes a little while to load)
ftp://ftp.zepto.dk/UserGuides/Nexus_A15/Nexus_A15_Manual_ENG.pdf

Do you think I should ignore this advice ?

 

Strictly, LiIon batteries do not need any preparation. They can be used as soon as they have some charge. From the second part of the first sentence in that section "the same goes for your battery if the capacity seems less than it should be", I think they are recommending a full charge/discharge cycle to calibrate the batteries internal fuel gauge before it is used. I can see the point in doing this, but, I have never done it for my laptops and have not seen any problem with the displayed charge level.

As to the full discharge, the issue is that a "deep discharge" of LiIon cells is very bad for them. The deep discharge is dropping the cell voltage below a certain point (sorry, I don't remember the value). But, all LiIon batteries (a battery is a collection of cells) have a protection circuit to prevent this happening. If this kicks in, it is possible that it will disable the battery completely (it won't accept a charge even though the cells inside are still OK). So, the recommendation is something like "avoid frequent full discharges". Doing the occasional full discharge/recharge cycle to calibrate the batteries internal fuel gauge shouldn't cause a problems.

My attitude is that laptop will shutdown when it the battery hits about 3% charge. If I plug in and charge within a couple of hours, it won't hit that deep discharge level and the battery will be fine. But, if it was left in this state for long enough, the inherent self-discharge of the batteries could drop the charge level enough to trigger the protection circuit and disable the battery.

David

 

Ahh, so discharging the battery whilst in the BIOS won't 'deep discharge' the battery as it will switch off before it gets that far, but if I do this then I must make sure I charge it back up straight away to avoid having any problems.

Thanks for the advice that's really helpful!

Tom

 

I tried to search this thread, (I did read about 15 pages), but did not find any reference to Sony Vaio Battery Care Function. This option allows users to set maximum charge to 80% or 50% or set to any % by user when AC is connected all the time. My question is, should I use 80% or 50% or 40% as maximum charge (i.e., it stops charging once that % is reached).

 

It will stop charging at your desired level but, if it is still plugged in, the battery will heat up more than it should, resulting in cell degradation.

 

Why? Assuming you are talking about the Vaio function mentioned above, it is most likely that the charger will simply be turned off. Hence, there won't be any current and heat applied to it (apart from heat coming from the rest of the laptop). This is also what happens for other laptops when the battery charge reaches 100% - the charger turns off.

 

Well if connected it will gain heat from the system. I can only guess what was meant but suspect that is the meaning?

 

how long can you store a battery say on a shelf before it starts to loose its ability to hold a charge. assuming its being stored at 40% and a cool dry place

 

I have been saying the shelf life of LiIon batteries was two to three years. But, reading The Battery University page http://www.batteryuniversity.com/parttwo-34.htm, they have "A lithium-ion battery in use typically lasts between 2-3 years." I thought that was where I got my number from.

Further down the page is a table of capacity loss at different temperatures and charge levels. You can look at that and read the page and make your own conclusion (mine is: It's not worth it).

David

 

Thank you for the guide, it puts me at ease since I just got a Lenovo T500 as my first notebook.

I might have missed it on the first page, but what should my cut off point be when charging the battery? I set mine to stop charging at 90%. Should it be 100%?

 

Does the T500 have an option to set the maximum charge level? If so, I can't think of a reason not to set it to 100%. I can see reasons for the 40% level, but once you go past this, you probably should fully charge it. The laptop and battery circuits will prevent it from going past 100%, so it is safe to do this. And it won't constantly charge it. When the battery level reaches 100%, it turns off. Then it will only turn on again when the charge level drops to a certain point (95% in the laptops I have checked).

David

 

I've got a question. I've tried to research this but I can't seem to find many answers. I have a Dell XPS 1530 and it came with the lowest Dell battery option possible. When I'm not hooked up and the "power saver" feature is on, it'll still only run about an hour and thirty minutes, hell, less.

Is there a way to upgrade the battery in this situation? What do I upgrade it to, and where can I buy it?

 

Since I essentially use my laptop (hp g60-120us) as a desktop and rarely use the battery, I have taken it out and stored it with a 40% discharge. My question is , when I shut down my computer at night, is it okay to unplug the AC cord from my laptop when I have taken the battery out? Does this effect the laptop in any way? Also, if I never use the battery, and it stays stored for months at a time without use, should I calibrate the battery at all? Thanks for the thread, I've learned a great deal concerning batteries.

 

Where have you read all this info that you have in this thread? Not from a proper manual!? I've read this in my manual (and many other has the same info in the manual as i do)


"Instruction for Laptop Battery (Li-Ion)"

Question: Should i take out the battery when i use the AC-adapter?
Answer: Generally speaking, the battery will be charged when the power lower than 95%. so Just as you like.
But we advise that do not take out the battery. It is helpful to keep the date better. If necesseray for you to take out. Please do remember to charge them in time and keep them properly as we mentioned.

And this is the only thing it says about using the battery to make it useless (nothing mentioning about it being fully discharged (when it's been fully charged) would harm it, not anywhere in the manual, but you say so, why?)
Do not make the battery be short-cycle. It will be affected serously.


The manual never says it should charge when it's 10 or 20% or anywhere near this, shouldn't it tell if it's important (as you say?). As the manual tells all other flaws, why would they forget something important like that?


Sorry for asking, but my thoughts gets split when i read your thread and my manual. And for the sakes of all the readers and handling their batteries this info should be good to know. (i've never read a manual that's been wrong so far)

I've done as the manual told me so far, completely discharging it several times, making the batterytime better when it's new. And what the manual has told me so far, has been correct according to my battery and how it works atm.

 

Manuals sometimes regurgitate accepted wisdom.

The better lion battery manufacturers have now incorporated auto shutoff circuitry to prevent usage below a certain level. They learned the hard way that over exhaustion leads to premature failure.

 

The information is from personal experience of the people posting plus reading on other sites. If you look at the end of the guide, there is a list of links. The one for the Battery University is the primary one to look at. It has detailed information about all types of rechargeable cells.

This is describing the behaviour of that laptops charger. It matches the behaviour I have seen in my laptops, though the manual doesn't mention it. It also matches the recommendation of recharging the battery when you can.

All the laptop manuals seem to say this. It probably comes from a safety point of view: less likely to have loss of data if the laptop loses power, less likely for something to get into the laptop or short out the battery contacts.

But, a lot of people who always use their laptop on AC power. These people want to make sure their battery lasts as long as possible for when they do need it. They want to take the battery out because heat will reduce the batteries life, and as the insides of a laptop tend to be hot, they are worried that this will affect the battery.

Personally, I think the battery belongs in the laptop. But, I use my laptop on battery during my commute most days. Plus I think the benefits of having the battery in (power backup, being able to move around the houses) outweighs the loss of life that results from having it in the laptop.

The laptop manuals I have read have been fairly simplistic in their instructions for the battery. Basically, they say "put it in, charge it completely and leave it in the laptop". My ASUS manual is slightly better but is still a summary of what to do.

This is the usual recommendation in the manuals. It is to calibrate the power levels in the laptop and battery. It is also a recommendation made for other battery types (NiCad and NiMH) to initialise them properly. In the early days of LiIon batteries in laptops it was also recommended for this, but it is not needed. There were also a lot of recommendations that you must completely discharge the battery before recharging them. But, this was a rule for NiCad and NiMH batteries that people assumed was true for LiIon.

As I said, the manual has simplified instructions and will not do anything dangerous. If you follow your manual, you will get a reasonable life from the battery. The instructions in the guide and the discussion since is about getting the longest life.

David

 

Ok, I didn't have the time to read through all 28 pages but I read quite a few stuff that are proving to be very useful in my case! I own a gateway P7811FX laptop with the 9-cell battery that came with it! I have been keeping the battery out of the laptop (in a case) at a ~10% charge (or less a couple of times)! I realize now that this was a mistake! Well after performing 5-6cycles I noticed that a software calculated my battery's health at ~95%.
Now I am still keeping my battery out of the laptop but at around 40% charge! The very few times I had to charge it and rely on it, it proved to be worthy of every $ I spent, lasting easily over 3 hours (3 1/2 to be accurate), with light use (web browsing and playing a pps presentation).
So far I am very happy with it!

Keep up the good work!

 

With reference to the original post on battery wear estimates, don't modern batteries report their last full charge over ACPI? As far as I know, the difference between this last full charge and the rated capacity is the 'battery wear' and is a completely valid statistic.

Also, for Dell batteries (at least for the XPS M1330), pressing and holding the charge indicator will flash the lights indicating the battery wear: one light for little to no wear, all five lights for over 40% capacity loss. It's in the manual, but I can't find a link at the moment.

 

Hi, thanks for the excelent guide. I have a question regarding the vaio's battery care function.

According to Sony:
There are three different options in the Battery Care Function Settings section:
Battery Care Function - The battery charge level will be about 80% of a fully charged battery, however, this mode prevents battery degradation and is more effective if you usually use the computer with battery power.
Super Battery Care Function - The battery charge level will be about 50% of a fully charged battery, however, this mode prevents battery degradation and is more effective if you usually use the computer with the AC adapter.
The settings for Battery Care Function on each battery - This selection gives you the ability to customize the battery settings. If this option is selected, the battery charge level can be set to either 100%, 80% or 50% by clicking the down arrow and selecting the desired charge level.

I understand that the "super battery care function" should be used for laptop which use both battery and AC adapter to prevent battery degradation. But, I use battery power on my vaio laptop most of the time. Are there any benefit if I use the 80% battery care function?? Or should I turn off the battery care function and charge the battery to 100%?

Thanks

 

I think the idea is that there can be a reduction in overall life if the battery is held at 100% charge all the time. The recommendation for long-term storage is to have it at 40%. So, charging to 80% is a compromise between this and having battery power available when you need it. Using this might be a good idea if the person was using the laptop only ever used it on battery for about half the battery charge. But, if you are using it more than that, you will probably want to go to 100% charge to get the maximum life. Also, if you are constantly using it on battery, it won't sit for any time at 100% and hence the likelihood of damage is small.

David

 

Hi folks,

After reading this guide and several other referred to in NBR I have come up with this method of madness for myself ... please tell me if I am shooting myself in the foot with this method ...

Whenever I am on my laptop ... usually 12 to 15 hours or so ... I let my Battery run down to 30% and then I charge it back up to 100% and then I unplug and run it down to 30% again ... and so on.

Q1: Am I using up too many Charge Cycles?
If not ... should I set up my LOW alarm at 20% or lower instead of 30%!?!?

Q2: May be I am better off leaving the Battery Out and just plug into the AC Charger? I am Always next to an Outlet!

Q3: Can I just Store my Battery in my laptop case (at 40% chrage level) and take it with me back and forth to Work!?!? Ambinet Temp runs approx. 70F.

Thanks,

G!

 

Yes.

Don't worry about it. Just use the battery as you need to.

If you read everything in this thread, I am sure you will have seen my opinion: Just put the battery in and forget about it. Use the battery when you need it. Plug in and use AC when you can.

Yes. To me the storage recommendation of "40% sealed in the fridge" is for long term storage. According to Battery University, storing at room temperature is not as effective, but is better than he higher temperatures that might be seen when installed in the laptop.

David

 

Hi David,

Thanks for your input. OK, you got me ... I meant I had read this Thread before ... may be before your postings ... but now I will do a search and check out your postings here.

Thanks again,

G!

 

Hi guys,

I was re-reading the Battery University guide and clearly suggests to do this

So, it seems my best bet is to unplug the battery and let my laptop stay on AC plugin all day when using it and only put in the Battery when I am in a remote area with no power.

The reason I am concerned is because I have an Old (~2000) "Dell Inspiron 8100" laptop that has a Li-ion Battery, type 75UYF ... I always kept my Dell plugged into the wall charger ... welll this Battery holds it's charge only for about 40 minutes and then is dead as door nail. So I am assuming my mistake of having it plugged into the wall charger all the time caused this battery loose it's HOLD Capacity.

Thanks,

G!

 

This is where people disagree. But first, some facts:

- Your battery does not stay on charge all day. The laptop charges it to 100% and then the charger turns off. This is done because Li-Ion batteries cannot take a trickle charge and if you tried, it would damage the battery.

- Once the charger is turned off, it doesn't turn on again until the charge level drops to some defined point. In all the laptops I have checked, this is 95%. If you want to check, charge the battery, disconnect from power and let the charge drop to 98%. Plug in again and battery state will stay the same. Unplug it again and wait for the power to drop to 94%. When you plug in, the charging will start again.

- All batteries suffer from self-discharge (loss of charge with nothing running on it). Li-Ion batteries have very low self-discharge. If the laptop is always plugged in, the battery level will slowly drop charge until it hits the point the laptop will then recharge it. This should be happening less than once a week. I use my laptop on battery to often to have ever hit this.

Because of the above, I don't think there is any point in taking the battery out of the laptop. Except maybe for long term storage. If you are not going to use it for a month or more, then storing it properly is a good idea. But if you are using it even weekly, then I don't think it is worth it.

But:

- Heat is the enemy. Li-Ion batteries loose capacity with time, "aging". Low temperatures slows aging and high temperatures speed it up. As the inside of a laptop is hot, it stands to reason that this will cause the battery to get hot and hence increase the aging. So, a lot of people think it is better to take the battery out and protect if from this heat. My experience says this isn't so as when I have pulled a charged battery out of a laptop, it feels to be at room temperature.

- Li-Ion batteries are good for somewhere between 300-800 cycles. Each time you disharge and recharge the battery a cycle or part of one is used (the drop to 95% mentioned above is a twentieth of a cycle). Some people think they should remove the battery to minimize the number of cycles used.

There is the argument. Some people want to do the most to maximize the lifespan of their battery, so they take it out of the laptop. I am of the opinion that it should be used, so leave it in and use it when desirable.

You have an eight year old battery and still get 40 minutes life from it? That is very good. As mentioned above, Li-Ion batteries lose capacity with age. The expected life of a Li-Ion battery is to or three years. The drop in life is due to age, not anything else.

David

 

Hi David,

Your explanation made sense to me ... so I am going to just use the darn Battery and leave my laptop plugged into the wall as always.

I ususally turn my laptop on at about 7:00ish AM and not turn it off till about 10:00ish PM ... so over 15 hours. This is 7 days of week.

Thanks for taking the time and going thru the explanation ... very useful!

G!

 

Hi all,

I have the follwing question.
I recently bought the computer you can see at the sig and browsing through DELL's Control Point Power Management I came to an option that allows me to stop the battery from charging when the laptop is plugged in A/C and will do so when I hibernate or switch off.

Activating the option would allow the battery to survive a bit longer?
Is this something you would recommend doing?

Tnx!

 

Noone has ever used this thing?

 

I have a very very old DELL (and newer Gateway) ... DELL usually does not put something out there that does not help the user ... so if it says it will lengthen the life of your Battery ... go for it.

But according to most of the Battery Guru's here the new Batteries pretty much stop Charging once they hit 100% ... so ... But if DELL has given you an application to "ensure" that ... then I would go for it.

BTW, I believe there is a DELL Forum here ... so see if anyone know about it specifically!

G!

 

I wouldn't expect so. What it sounds like is it is only charging the battery when the laptop is not drawing power to run itself (the laptop is off or hibernating). This would lower the maximum power usage of the laptop. I can think of two reasons for doing this:

- Running the laptop from a power source other than mains power (maybe from a car). It is possible this might not supply enough power to both run the laptop and charge the battery.

- Heat. As the insides of a laptop can get hot, and charging the battery will warm it a bit. Only charging it when the laptop is off would reduce the heat and that might help extend the life of the battery. But, I am not convinced that it would be worth it.

Personally, I want my battery charged again as soon as possible so that I can use it if needed.

David

 

Hi folks,

OK I have a Quiz for the Regulars at Notebook Battery Guide at NBR ...

Let's assume that as they say a Li-Ion battery is good for somewhere between 300-800 cycles. And I will pick the high-end number 800 cycles.

Now let's say I charge my laptop battery to 100% and then I unplug it from the AC Charger and let it run down to 30% (I picked this point ... since I concluded it to be a good point from readings ... ) and then charge it back up again to 100% and repeat this cycle back and forth.

If I have my laptop turned on for 12 hours or more a day and I have it on 30 days in a month and each cycle - charging routine as above lasts for about 2 hours ... usually 2.5 hours but for the sake of simplifying my math I'll go with 2 hours ... that means

12 hours / 2 hours X 30 days = 180 cycles.
So 800 cycles max / 180 cycles in a month = 4.44 about 4.5 months (4 and half months).

SO my laptop battery should be dead as a door nail at the end of 4.5 to 5 months time frame!?!?

Q: So why is the battery goes on for few years though???

Thanks,

G!

 

That's the figures given.

So each time is a 70% cycle. Doing this ten times will be the equivalent of doing seven 100% cycles.

Are you serious? You are actually doing this? WHY?

And you missed the discharge part of the cycle. If the charging lasts for 2 hours, then hopefully the battery lasts for the same time. So that means a cycle is 4 hours.

My calculation is: 12 /(2+2) * 30 = 90 cycles and hence about 9 months life.

I don't know. If you are actually doing what you are saying above, then I would expect it to be dying in the time you calculate. There is some suggestions that frequently charging the battery is better for it than letting it run out.

Also from memory of my reading of the Battery University site, the number of cycles is an expectation. There are plenty of people reporting longer live and plenty reporting less life. Maybe you lucked out.

Personally, I use my battery for about a 70% cycle each working day (on the commute home). The laptop is on most of the time (sleep or hibernate in my bag when travelling and not in use, left on overnight but goes to sleep and hibernate after some time). My life would be:

0.7 cycles * 5 days per week * 4 weeks per month = 14 cycles per month. That works out at about 57 months or 4.7 years. As there is also aging to take into account, a two to three year life (until it doesn't hold enough charge for it to be useful) sounds about right.

David

 

Hi davidfor,

As usual an interesting & thought provoking reply.

Thanks for your reply & time!

G!

 

How come when I try to run on AC power and take the battery out I cannot connect to my broadband connection? is this normal? because its awfully weird it seems.

 

Hi folks,

For what is worth since my last Q&A (discussion) with Davidfor ... I decided just to plug into the wall AC outlet and leave the battery in also ... To my surprise ...

- Battery does not get as Hot or Warm.
- My AC Charger does not get as Hot & Toasty as before.

Bottom line don't make your life miserable ... worrying about your Battery ... just plug into the wall and use as is ... I think the darn battery will last much longer and better.

G!

 

Another convert!!!!!

David

 

This is a sweet guide man, thank you very much. I'm going to put this to very good use.

 

my vaio has a setting to automatically limit the battery charge at 50% to help it last longer.

is this good?

 

should i NOT leave my battery plugged in and have my power cord attached at the same time then?

also, to calibrate my battery i let it reach the cut off, and then i turned it on again and let it go to 0% and then plugged it back in (well, tried turning it on again and it shut itself off). was this wrong? should i NOT go to o%? im scared something could go wrong if it goes to 0% and shuts itself off.

thanks

edit: i have no idea whats going on with my battery now. it shows that it is at 96.4% when unplugged, but when i plug it in it shows that it is 100%. the odd thing is that the correct charge capacity is being shown when it is at 100% and when it is at 96.4%.

what the heck is going on??! batterybar shows no wear, neither does RMclock. It seems that by trying to calibrate my battery i UNcalibrated my battery. fantastic. i wont be calibrating anymore :\ And definitely not to 0%, because apparently there is no consensus whether i should go to 0% or not.

 

in addition, is it okay if my voltage (according to RMclock) is higher than the rated voltage?

 

I am currently using a setting that uses AC power but does not charge the battery (while the battery is connected).

Will this still overheat the battery?

I figure this is better than constantly charging the battery or letting it drain for no reason if im near an outlet.

thanks

 

What laptop are you using that allows this?

There are three reasons a battery in a laptop can be heated. Two of them are when the laptop is running on battery or charging the battery. In both cases it is normal for the battery to become warm. If it gets hot, then there may be a problem.

The other reason is heat from the laptop. In this case, how hot the battery gets is dependent on how hot the laptop is and where the battery is. I have some old Dell C-Series laptops. In these, the battery is at the front and all the hot components are at the back. The battery in these don't feel like they are warmed by the laptop. My current ASUS F3Sv has the battery at along the back. The fans exhaust is next to the end of the battery. This would have the potential to have heat go to the battery. But, I have never noticed it to be warm - it always feels to be at room temperature when I have checked. To know if it is a worry for you, you will need to check the battery temperature.

To start with, your battery is not "constantly charging". It is very bad for Li-Ion batteries to be charged once they are full. So, unlike other types of rechargeable batteries, they cannot be trickle charged and Li-Ion chargers turn off once the battery is full. And, at least with all the laptops I have checked, the charger does not turn on again until the battery level drops to 95%. Unless you run the laptop on battery, the only reason for the battery charge to drop to this level is through self-discharge. All rechargeable batteries self-discharge but Li-Ion has the lowest rate. Based on my use over the Easter weekend (battery recharged on Thursday night after my commute home, laptop running on power until Tuesday morning - about 4.5 days), as the battery had dropped to 98% it would take over 10 days to drop to 95% and trigger charger to turn on (Note: this will never happen as I use the laptop on battery during my commute and frequently while at home).

With what you are doing, the battery is still self-discharging at the same rate. Eventually you have to recharge the battery so you can use it. And if you don't, it will eventually self-discharge to the point where the battery protection circuit will prevent the battery from being recharged (this is actually below the 0% level). Li-Ion batteries are not harmed by either frequent small charges or less frequent larger charges.

What all that is supposed say is that I don't think there is any advantage in what you are doing. If you take the battery out and store it correctly, there is. But if it is in the laptop, it may as well have a full (or near full charge) so that you can take advantage of having a laptop and move away from a power point when you want to.

David

 

Batteries that are from a different manufacturer can be dangerous, I heard from a news that some electronics like mobile phones and laptops can explode or shock the user when the improper battery is used...

 

Off brand batteries in general are made to the same saftey standards as the originals. The factory we use actually makes some "originals" as well as a number of generics so we are very familiar with the process, as well as with exploding batteries etc..

Recently improvements in electrode materials has limited the possibility of explosions, but not ruled them out altogether. Safety features on all LI-ion batteries include

shut-down separators for over-temperature (cuts circuit if it gets to hot)
tear away tabs for over-pressure
blow out vents (to allow controlled release instead of explosion)
overcharging/over current disruption chips

These are built in to every Li-Ion battery I have ever seen. Problems today usually stem from bad cells that are self-discharging due to impurities, bad chargers, damaged batteries, design problems, or user error (using the wrong charger, charging the battery backwards, etc..).

These problems are not significantly greater for off-markets than OEM from my experience, in fact most are made in the same or similar factories using the same suppliers so you would expect similar problems.

The biggest problem I have experienced with off-market batteries is IF the Li-Ion cells are not high quality the charge that they hold is significantly less. So we for instance pay more for high quality cells, it bumps the cost of the batteries up some, but we find that our customers have a lot fewer headaches and therefore we have a lot fewer headaches.

Good Luck,
Chris
Sterlingtek

 

I do the same and I think we have the same notebook. My battery stays at 99%. What I wonder though is every time I boot the computer, I am unable to disable the battery charging until I get to the Vista login screen so the battery is charged for maybe 15 seconds when I boot. Would this have any effect on the battery's life?

I don't think this overheats the battery. The rear of the E6400 stays pretty cool most of the time. Most of the heat happens at the front and this happens only under load.