As the battery life on my notebook appears to grow less and less with every recharge, I’ve come to wonder if leaving my laptop plugged in all the time has taken an effect. I know there are many out there who are probably experiencing the same issue, so I decided to do a little research on the subject and came across an interesting article directly addressing this issue.
The truth is that laptops and laptop batteries are designed with the intent that they are plugged in as often as possible. In fact, most manufacturers suggest leaving them plugged in all the time. The heat you feel from the bottom of a laptop that’s been running all day doesn’t really have anything to do with whether it’s plugged in or not. Laptops get hot due to their internal components and the chemical reaction in the battery. The A/C charge has very little to do with it.
Will leaving it plugged in decrease its useful life? The short answer is no, at least not enough that you’re likely to notice. Lithium-ion batteries have no “memory effect” like nickel-based batteries, so there’s no worry about plugging them back in before they’re completely drained. But like all batteries, lithium cells lose capacity over time. The more they are drained and recharged, the more their internal structure warps, and they eventually become unusable. This happens due to heat, and since your battery gets hot even when it isn’t discharging, as long as you have it installed in a running computer, it’s going to be affected to some extent.
There you have it folks. It seems that there isn’t a noticeable loss in battery life by leaving your laptop plugged in. The constant draining and recharging of the battery is what actually lessens the life of your battery. But if you still believe leaving your laptop plugged in is killing your battery then here is a solution:
If you turn off your laptop at night and unplug it, or if you run your laptop plugged in, without a battery installed, that battery would last slightly longer when you do eventually start using it (so long as you keep it properly charged most of the time). However, the extra lifespan you gain is not even remotely worth the extra hassle in doing all this work.
Bottom line: Leave your notebook’s battery installed, and plug it in as often as you can.
Source:
Yahoo! Tech: Is It OK to Leave My Laptop Plugged In All The Time?
Related Links:
Laptop Batteries, Available at TigerDirect.com!
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I used to keep my laptop plugged in 24/7.
The laptop battery died after one year, and now I MUST keep it plugged in or it will automatically turn off when I unplug it.
its true me either
its like so annoying
you need to service it with a lot of payment
I tend to agree with Dan. Used to have my laptop connected all the time, battery lifespan got shorter by the month until it barely held a few minutes. Bought a new battery and now I’m draining until 6-7% then connect and recharge until 98% and battery is holding much much better. This article led me to this behavior: http://thisweekinbatteries.blogspot.com/2010/02/pull-plug-your-battery-will-thank-you.html
My wife has left her HP Pavilion notebook plugged in 24/7 for the past 5 years and the battery is still fine. The charge runs down to 95% and then the amber light comes on and restores the charge to 100% and the green light comes on. This happens about once per month. I have read that LiIon batteries can last for thousands of cycles if the discharge is kept very shallow. I have an old Dell that I have recharged every weekend and the battery is still good after about 12 years at this point. HP says the power meter will get out of calibration if the notebook is always kept plugged in. However, this keeps the battery on float and it seems to prolong battery life as much as is possible — well beyond the time to obsolescence of the notebook.
start unpluging your computers at night
What is written in this article is NOT true. Yes, Lithion batteries don’t have as much of a severe memory effect as the older nickel and cadmium types, but it isn’t to say that they don’t have it. Plugging it in as often as possible will shorten it’s lifespan. People who use their laptops as a desktop computer (plugged in all the time) can all confirm this. Keeping it plugged in will kill your battery quickly.
It’s better to make sure about 75% is drained before you charge your battery. You have to use it, to keep it working. And, to keep it healthy as long as possible, make sure to let it go through a deep-cycle at least once a month. This means draining it all the way, and charing it up to a 100% all the way.
And don’t forget: Heat is the number one factor in killing a battery. Don’t leave your laptop and the battery in your car during the summer, or out in the yard in the full sun.
I use my laptop as a desktop, keeping it plugged in all the time and my experience DISPROVES your statement. My batteries lifespan lasts as long as it did the day I bought it 2 and a half years ago, with no battery issues at all. I do not shut it down when I am done with it, and I always have it on the charger, no problems :)!
@DJS
Agreed coz I do the same to my laptops, and none of them had suffered any ill effect to battery life from staying plugged in. Many people simply have no idea what “memory effect” really is (something that technically doesn’t even exist in today’s electrolytes), and the astonishing part is the clueless people often include those who are supposed to be “experts” in the area such as engineers or very experienced electronics salespeople. The sad fact is most of them dispense advice by relying on past product specs (like the 8-hour first charge for mobile phones ages ago), or outdated science which is valid only when based on the parameters of the equipment in older days. They are a ton of factors that can reduce a battery’s life span and power level but keeping it on adapter power definitely is not one of them (unless you have a laptop from the Jurassic era of computing).
Does the Memory Effect Exist? Not in Research International’s Li-ion Cell. Yes and no. The ‘real’ memory effect as reported in certain space borne applications and caused by persistent under charging of a partially discharged cell is almost certainly never seen in mobile phone batteries or any others in terrestrial service except in certain very unusual circumstances.
Much more commonly, there is AN effect, properly called voltage depression, which people now tend to refer to as ‘memory effect.’ This is a bit unfortunate as the cause (and cure) is different from the true memory effect. For details, read on:
First, the term ‘memory effect’ is quite unscientific. People tend to attribute any failure of a NiCd to memory. Let us define memory as the phenomenon where the discharge voltage for a given load is lower than it should be.
This can give the appearance of a lowered capacity, while in reality, it is more accurate to term it voltage depression. Memory is also hard to reproduce, which makes it hard to study. Originally, memory effect was seen in spacecraft batteries subjected to a repeated discharge/charge cycle that was a fixed percentage of total capacity (due to the earth’s shadow). After many cycles, when called upon to provide the full capacity, the battery failed to do so. Since we aren’t in space, the above is not really relevant.
Voltage depression is more severe in NiCd batteries than in NIMH. The explanation below concentrates on NiCd, the same principles apply to both.
Let us look at Various Causes of ‘Memory’ or Voltage Depression.
Memory can be attributed to changes in the negative or cadmium plate. Recall that charging involves converting CD(OH) to Cd metal. Ordinarily, and under moderate charging currents, the cadmium that is deposited is microcrystalline (i.e. very small crystals). Now, metallurgical thermodynamics states that grain boundaries (boundaries between the crystals) are high-energy regions, and given time, the tendency of metals is for the grains to coalesce and form larger crystals. This is bad for the battery since it makes the cadmium harder to dissolve during high current discharge, and leads to high internal resistance and voltage depression.
The trick to avoiding memory is avoiding forming large crystal cadmium. Very slow charging is bad, as slow growth aids large crystal growth (recall growing rock candy?). High temperatures are bad, since the nucleation and growth of crystals is exponentially driven by temperature. The problem is that given time, one will get growth of cadmium crystals, and thus, one needs to reform the material. Partial cycling of the cells means that the material deep with the plate never is reformed. This leads to a growth of the crystals. By a proper execution of a discharge/charge cycle, one destroys the large crystal cadmium and replaces it with a microcrystalline form best for discharge.
This does NOT mean that one needs to cycle one’s battery each time it is used. This does more harm than good, and unless it is done on a per cell basis (impossible in a phone), one risks reversing the cells and that really kills them.
Perhaps occasionally, use the pack until it is 90% discharged, or to a cell voltage of 1.OV under light load. Here, about 95% of the capacity of the cell is used, and for all intensive purposes, is discharged. At this point, recharge it properly, and that’s it.
In the case of mobile phones the phones are designed to switch off at the 90% discharge point before the battery voltage gets sufficiently low to damage the individual cells so the phone itself make the ideal discharger —just leave the phone on until it switches itself off after bleating about your battery being low! Many so-called ‘conditioners’ actually take the battery down to virtually zero volts and far from conditioning the battery cause cumulative damage to the cells.
The more common ‘memory effect’ isn’t memory at all, but voltage depression caused by overcharging. Positive plate electrochemistry is very complicated, but overcharging changes the crystal structure of the nickelic hydroxide from beta-nickelic hydroxide to gamma-nickelic hydroxide. The electrochemical potential of the gamma form is about 40 to 50 mV less than the beta form. This results in a lower discharge voltage. In a six-cell (7.2 V) pack, this means a loss of 300 mV. Trick? Don’t overcharge. Leaving cells on a trickle charger encourages formation of gamma nickelic hydroxide. Expect the cells to discharge at a lower voltage.
My friend bought a laptop in spain. The battery failed during the guarantee. The manufacturer would not replace it because quote “It had been left plugged in all the time”
Thanks for the article. I finally had to give in and buy a new replacement laptop battery, and I wondered if leaving it plugged in was the reason it died so quickly. Now I know there’s not really much I could have done about it.
I have a Dell Vostro 1500, and have never damaged the battery. One time the plastic hinge cover broke and the monitor would fall without a support, so I had to use it as a desktop. Leaving it plugged in all the time DOES shorten the batteries full capacity. The Dell Quickset tools (that monitor the battery) don’t tell you this because they want you to buy a new battery. My battery cannot charge more than 29%.
I found this site due to the fact that a friend of ours argued that leaving the laptop plugged in will shorten the life of the computer. (This conversation initiated because I mentioned that I prefer to leave our laptop plugged in because the screen is brighter and therefore better on my eyes) He didn’t mention anything about the battery. I had no proof of arguement. I know he wanted to be right. I just want to know the facts so I can do the right thing. Thanks for all the tips.
Denise
Thia is what I founs in the my info center on my New Sony VAIO…
Battery life will be about 80% of the one of the fully charged battery, however, this mode prevents battery degradation and is more effective if you usually use the computer with battery power.
[Note] When you use the AC adapter to power the computer and the battery power is higher than the desired value, it takes time to reach the specified amount of battery charge. It is recommended to discharge the battery to less than 80% by using the computer with battery power.
I learned it the hard way…i kept my laptop plugged in all the time and now it won’t hold more than 15 minutes….
Same thing happened to me. Now I’m never leaving in plugged in for too long.
my laptop always plug in everytime I used it. Now Ive notice that the battery charging indicator is flashing, I don’t know what does it mean?
by the way my laptop is almost two years now and the battery lasts up to 1 hour only.
I keep my notebook always connected to the electricity source and the battery is still perfect. The notebook has more than two years. I know is better to empty the battery once at 1 month. After that, is better to keep the laptop plugged in.
I wonder if the people that say their batteries are still perfect despite keeping them constantly plugged in is because since they use the laptop always plugged in everything runs good. Just try to use the laptop unplugged and you will find out if the battery is still good.
I use my laptop just at home for a year, always plugged in, everything went fine until I started to take it with me and tried to use it unplugged that I realized the battery does not hold not even for an hour.
I plug my laptops in all the time while at home and not one of them had suffered a loss in battery charge capacity. The only one with any visible degradation was 17 months old and the battery still holds 80-90% of the charge it had when new. The loss in it can be safely attributed to chemical wear. Interestingly, my Macbook is 3 years old (thus older than my other Windows laptop above) and the battery is none the worse from the constant connection.
Well, I really don’t know anything more than when I started! I just got a new laptop and would give it a full charge, then use the battery to deplete it and then recharge…my last laptop was always plugged in and the battery slowly died. I guess I’ll go with the keep it plugged in notion because it’s a pain to keep plugging and unplugging and nobody seems to have a definitive answer!!
I have an HP laptop and the battery went bad in less than two years and kept it plugged in all the time. January 2011 I bought a new battery and now that battery won’t hold unless plugged in. I am sending it in under warranty. I don’t keep it plugged in all the time now and look…….so what’s the correct method? I think it is horrible the battery hasn’t even lasted a full year!
im not sure the correct method either and i cant seem to find out .i unplugg mine at night and it wont hold the charge more then 20 min but its fine if i leave it plugged in
I also studied that for a good battery life, the DOD (Depth of Discharge) should not go below 50%. That was for lead acid but I guess would hold true for Li-ion as well
I need to know if my battery in my laptop is dead, should I dispose of it and in the meantime, until I get another battery, can I leave my AC adaptor plugged into the wall all the time or should I unplug it at night.
To all those people who claim that their laptop still works perfectly, if not better after leaving it plugged in all the time have you unplugged your laptop long enough to know how long your battery lasts without being constantly plugged in? I only ask because I haven’t read any comments stating that even after keeping their laptop plugged in 24/7 it still holds a charge for hours off the charger – Mind you, I didn’t read every single comment. I only ask because I would like to know for sure the best option for my laptop. I’d like it to last as long as possible. So far I’ve had since september of 2011, and in the beginning I played on it all day, plugging it in when the battery gets low and unplugging it when it’s charged again, and then in the lasts couple months I started only charging it when I was on it and the battery was low, no longer charging it over night. My battery, while it doesn’t seem as good as it was new, still lasts 4 – 6 hours depending on what I’m doing on it, usually leaning more towards 4.
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