Does Leaving Your Laptop Plugged In Shorten It’s Battery Life?

Computers & Technology, Tech Tips 13 178
Battery Low

If you leave your laptop plugged in all the time, even when the battery is fully charged does it shorten the life of the battery?

That is the question that came up the other day and I didn’t know the answer, I always wondered myself as I use a laptop at work that is plugged into the AC power 99% of the time. Fortunately an answer to the question was very easy to find on the internet.

The short answer is yes, leaving your laptop plugged into mains power while the battery is fully charged will reduce the batteries capacity to hold a charge.  When the battery is running consistently at full charge it causes the battery to chemically kill it’s self.

The best solution for minimising the damage to your battery from sustained charge is to charge your laptop’s battery to 100% and then pull out the plug and run it off battery power until you need to charge again.

I am by no means an authority on batteries and electricity so I will leave you with the source of my answer here, from a man who runs a blog dedicated to batteries and who’s credentials include working with a team of researchers from the Lawrence Berkeley National Lab on the Batteries for Advanced Transportation Technologies (BATT) program, so I think if anyone is to be trusted on the subject of batteries it is this man.

A good question which was raised from the source article was from Prashanth who asked:

Don’t the laptop batteries have a limited number of “Charge cycles”. Won’t constant discharging and recharging of the battery use up these charge cycles thereby reducing its life time?

to which the answer was:

Yes and no. Yes in that cycling will decrease life. No in that the depth to which you cycle has a huge impact on life. The less depth you cycle to, more the life.

So you can either take my word for it or read Venkat Sriniva San’s article which explains the answer in great detail. Check it out here.

What are your experiences with this? Have you ever noticed your laptop’s battery life suffer because of this? Please comment below.

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  1. Bryan February 25, 2011 at 1:39 am - 

    Thanks for the info! This is a very important information. This helped a lot especially since looking for a decent battery to replace your original one can be hard.

  2. paul February 18, 2012 at 7:00 pm - 

    Thanks, I’ve using my laptop while plugged in but a friend told me it has effect on the battery life.

  3. NEWBIE April 5, 2012 at 6:43 pm - 

    This is an old view. Most Li-Poly batteries these days cut off upon full charge and run on AC power.

  4. Zubair May 28, 2012 at 7:13 am - 

    Thanks alot, I was looking for a sane answer with some engineering sense and reasoning. Points noted.

  5. Atreies July 4, 2012 at 6:19 am - 

    Saying that the battery stops charging at 100% is correct, except your forgeting to note that rechargable batteries lose some charge over time, not just with use. So one day your battery is 100%, the next it might be 99%, it will charge itself again to 100%. A miniscule lose of battery life to be sure but when you take into account this happening over 2 years it will shorten the life of the battery. Factoring in degradation from heat over this 2 years has more impact. Charge your battery and if you not going to need it for a peroid of time then remove it and leave it out till you need it or till enough time has passed to charge it to be ready for next time.

  6. phil July 12, 2012 at 4:57 am - 

    My laptop is 1 year old. It is always plugged in and has died several times. Why ?How do I stop this?

  7. Haaris August 15, 2012 at 10:40 pm - 

    Phil: By a new battery, mate.

  8. Andy August 21, 2012 at 1:00 pm - 

    Forgive me but doesn’t this fact make laptop designers the stupidest people in the world? Why doesn’t the charging system accommodate this most obvious of behaviors. Why are we forced to cycle our batteries unnecessarily just to maintain them. We have to shorten the batteries life to extend its life. It seems like an oxymoron.

  9. neo eltro September 22, 2012 at 6:23 pm - 

    Thanks for information. I will now charge my battery below 70% every time.

  10. Matt October 18, 2012 at 11:23 pm - 

    I usually don’t leave my laptop plugged in past full capacity, but yesterday I accidentally left it charging overnight. When I unplugged it and turned it on this morning, it was at 44%. Could someone explain why? Is it a fluke or did I damage the battery?

  11. Bill February 13, 2013 at 9:00 pm - 

    Your sources refer to vehicle batteries you muppet! It’s articles like this that spread yet more bullshit throughout the wonderful world of the internet.

  12. Ben February 14, 2013 at 12:14 pm - 

    Check your facts bill before you call bullshit Bill. Did you even read the article properly? They refer to vehicles but the article is about laptops. Idiot.

  13. mens denim jacket with patches April 14, 2014 at 8:38 am - 

    Ԍood post. I’m experiencing some of these issues as well..

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