For normal laptops, everyone said that if you want to use your laptop for a long period of time at home, its better if you detach the battery and just connect it directly to power. I followed this practice with my old laptop, turning it on when I woke up and turning it off when I went to bed.

I bought a Lenovo Yoga 2 Pro a while ago, which is an ultrabook. The battery is non-removable. Is it OK to run it 12 hours a day continuously on the charger? Will the battery be harmed?

  • 2
    Who said that? With most laptops you should leave the battery in the device. If the device has a setting to limit charging to 60-80%, use that, and leave it plugged in all the time. Otherwise use it with charger and without, alternating. Apr 30 '15 at 1:21

So should i keep the y2p and just connect its charger all the time or get a laptop that has a removable battery? like maybe a macbook or something?

Recent Apple laptops aren't designed to allow you to remove or replace the battery (see here for an example) so would be a bad choice if that is that is really something that bothers you.

Also, Lenovo laptops normally come with a program called Energy Management where you can control battery charging, if you don't have it already then you can download it here.

As far as I am aware, this laptop supports Lenovo's standard Conservation mode as explained here:

This mode in energy manager affects the firmware on the battery, and stops the charging when it reaches 60%.

In some cases, not charging the battery to 100% constantly may improve the overall lifespan of the battery with the trade off being that you will have less run time on a charge because you are only using 60% of the battery capacity.

This setting is most often suggested for a system that is always Plugged in to the Ac adapter,

If you keep the laptop plugged in all the time then in theory this may help although it's debatable whether this is really necessary.

  • I have a Lenovo, though not the Yoga the OP mentioned. Mine only opens about 270 degrees and has a removable battery. Anyway, I can confirm the Energy Management app does have the conservation mode, though I wouldn't fully trust it. I think it cycles between charging to 60% and then draining it to a level close to where Windows would still have enough time to enter Hibernate mode if the power failed. I unplugged my laptop once with Conservation mode and I only had about 10% remaining (got the 'low battery' warning after 5-10 minutes).
    – ps2goat
    Apr 29 '15 at 15:20
  • A normal full charge would be good for 4+ hrs of standard development work. However, the software can integrate with Outlook so it knows to charge the battery fully before you have a meeting, in case you need to give a presentation without connecting the power adapter, for example.
    – ps2goat
    Apr 29 '15 at 15:21
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    @ps2goat: I used to have a Lenovo and used the conservation mode since I almost never used it on battery and I do agree that it seems that it can cause the battery charging calibration to go a bit wrong although it wasn't quite as extreme in my case. The solution seemed to be to occasionally switch to the normal charging mode, do a full discharge followed by a full charge then switch back to conservation mode and this made the percentages more accurate.
    – James P
    Apr 29 '15 at 15:26
  • Thanks for the awesome answer. Macbook was just an idea, since i wanted to try os x... i meant any normal laptop with removable battery not just macbooks. I do have the Conservation mode, but i don't use windows all the time, my main os is ubuntu. i don't know if there's a way to do this in there?
    – Soheil SH
    Apr 29 '15 at 15:56
  • 1
    @SoheilSH: If you enable it in Windows it should then affect Ubuntu as well since it is affecting firmware built into the charging circuitry. That is why the behaviour still works if you charge with the laptop turned off rather than when it's on and running Windows.
    – James P
    Apr 29 '15 at 16:01

The suggestions for the treatment of li-ion (and li-poly) batteries to keep them cool, and at a lower charge state are simply that, suggestions that will give it the best chance to survive for more time (as in years).

Li-ion prefers to not be as hot as it can get while in a computing device , which includes phones, laptops even power boxes using them. They degrade faster at the higher temperatures.
On the other hand they have been doing this for years this way, and it is not a huge problem or makes the devices or the designs unusable, it is only a not best practice.

Li-Ion degrades internally faster when it sits for longer at higher charge states, which happens when the device is plugged in continually, and has no provision for a lower charge state (often referred to as a battery saving method).
On the other hand , they have also been doing this for years, and devices still exist in plenty with no curcuitry or software to do any different. the devices are all still fully usable, mostly safe, and work just fine that way, it is just not the best possible method.

Side Notes:
There is a limit to how many times they can be charged and discharged also, so there can be a balance between using it down, to have it be down, and rechaging it eventually or having it be useless when needed. The method of storing it at a lower state , is mostly about storing it, not using it.

It is also not good to have it discharged below spec, which can occur when it has little to no charge, and is left out of the device for way too long without a charge.

Conclusion :
When you read about good methods to preserve and increase the longevity of the battery in your devices, it is just that , ways to make things better for longevity. The devices are still working within specs (for the most part) and function just fine. For as long as they will, because the battery will someday need to be replaced.

The methods have every bit of science and proof behind them to be real actual life of the cells methods to increase longevity, and are not fake, it it just not always practical to do that, and it is not always possible to do that, or even find a good balance.

  • Thanks for your answer man, but my english isn't so good and your answer was mostly really technical and confusing! i didn't really exactly understand things you said above "Conclusion". So you're saying that i can leave it plugged in all the time but eventually the battery breaks but the device can still work without a working battery? Can you explain in a more simple way? Thanks.
    – Soheil SH
    Apr 29 '15 at 9:31
  • Oh, I thought you already had a understanding of the issues, from your question. Because your feelings about it were correct, you can treat a battery better if you can remove it. I just do not think that is a reason to not use what you may have. You can Leave it in the device, you can leave it charged , it will evetually die, and NO old li-ion batteries should be disposed of properly, if the battery is way to old, you would not want it in your device any more.
    – Psycogeek
    Apr 29 '15 at 9:39

I don't know how this "everyone" is, but if you remove a battery from any MacBook with a removable battery, then the clock speed will be drastically reduced. The reason is that the charger supplies a limited amount of power, and it is possible that the laptop would for a very short time need more power than the charger can supply. For example, if all cores are running simultaneously, and then you spin up the hard drive while writing to the DVD drive. With the battery plugged in, no problem because the battery will supply the missing power. Without battery, instant crash. And to avoid this, the clock rate is reduced to the point where the MacBook cannot possibly use more power than the charger supplies.

The reasoning is not in any way Mac specific, so I would assume that any good laptop would do the same thing. Alternatives are supplying an absurdly huge power supply, or crashing if the user pushes the machine without battery.

Some people recommend discharging the battery maybe once a month. Worst case this is 60 charges in five years which shouldn't make any difference to the life time, best case it may help. And it's definitely better than using your laptop without charger every day until it is empty, and then charging it (which some people did because they were told to discharge the battery from time to time and did it daily instead of once a month).

The best rule is probably not to worry about it, keep it plugged in when you are near a charger and not plugged in when you are away from a charger, and only if it is plugged in all the time use it without charger once a month, and again, not worrying about it. All batteries can be replaced.

  • All batteries can be replaced. Did you know that batteries cost something and that they can be quite expensive?
    – idmean
    Apr 29 '15 at 20:03
  • 1
    Yes, leaving the battery in is recommended for most laptops. For best battery life the laptop should be set to only charge the battery to 60-80%, if such a setting is available. Otherwise, alternate having the battery on/off charge (but avoid running it flat). Apr 30 '15 at 1:25

The answer is complicated. And I hope it will answer future questions like that. But please edit question so it has relevance (add something like: battery life and life cycle)

First you have to have an idea how battery works. In short, it is an chemical compound container, which generates current from chemical reaction. That it can be charged and discharged is beside the point. Since it is an chemical reaction device it will get used up - that is: will store less and less charge. Battery when charges generates heat. The higher the temperature of battery during charge the shorter it's lifespan will be. In short: high temperature kills battery. By "high" it's understood anything above 40 C (104 F) degrees.

But battery is not the only source of heat in a portable computer (no matter what kind). So, if you roaming a lot and using your machine a lot and - obviously - will be charging it a lot WHILE SIMULTANEOUSLY using it, you will eventually trash your battery. Which is sort of EXPECTED.

On the other hand, if you remove your battery you better make sure it is half-charged or so (40% charge is best) and you still have to discharge and charge again every 2-3 months or so for it to keep it's nominal capacity. because unused battery will get used also (remember? chemical reaction?). There are suggestions - not stupid, let me add - that unused battery should be stored in the fridge (not freezer, though), but... Exactly: but.

So, if you use your machine a lot when connected to charger, but the battery is fully charged, it doesn't really matter if you remove it or not. It's simply because the battery is on support current only then and is not being really charged, thus not really impacting it's condition. Better to have it, because machine is better balanced and more stable with it.

And final answer is this: if you want your battery to last as long as possible, you should ALWAYS charge it with computer powered off, so the battery can be COOLED by the bulk of the computer rather than extra heating it.

And the (sort of) explanation for that is: since battery is a chemical reaction device it is EXPECTED it will loose on average 20% of it's nominal capacity a year. Depending on actual, individual usage way more or way less. Mine, for example, are at 20% nominal capacity after 2 years, as I'm very aggressive roamer. There's no way around it, actually. That is also, incidentally, why the battery is covered by 6 months warranty at best by manufacturer. And that's why the batteries are cheaper than before and why there is huge market for non-genuine replacement parts like this. I recommend to bite the bullet and just calmly await time when battery needs to be replaced, then find non-genuine product with lots of positive comments on ebay.

So, armed with that knowledge, you have to decide for yourself what to do. You can, usually, open your machine and remove battery, but with tablets it's delicate (although rather easy) job. Is it worth the (minimal) risks? And you will handicap yourself - ending with a tablet you cannot quicky take with you, even to another room is for me too big a utility loss. But it's your decision.

  • There's some good advice here, but the physical chemistry portions are... badly confused.
    – Ben Voigt
    Apr 29 '15 at 15:37
  • Thanks for your answer. but i obviously can't/don't want to charge it when its powered off, because i want to keep it connected and powered on 12 hours a day...
    – Soheil SH
    Apr 29 '15 at 16:07
  • @Ben Voigt - Can you be more specific so I can amend answer?
    – AcePL
    Apr 29 '15 at 17:40

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