“Should I leave my laptop plugged in all the time?” is one of the most common questions a new laptop owner always finds themselves asking. Today we find out why this is or isn’t such a good idea.
The short and simple answer to that question is no. You should try to avoid leaving your laptop plugged in and charging all the time to avoid battery degradation. Though there is a lot more to the story than just this.
Most laptop batteries these days are either lithium-ion batteries or lithium polymer batteries. While the names may sound different they are pretty similar in how they operate.
Before we talk more about why you shouldn’t leave your laptop plugged in all the time. Let’s talk about some common laptop battery myths and facts.
What does Overcharging & Discharging Your Battery Mean?
Overcharging
You must have had a family member or friend give you advice on how you should never leave your electronics plugged in charging all the time as that can “Overcharge” the batteries.
Well let us be the first ones to tell that there is no possible way you can overcharge your laptop battery. By leaving it plugged in all the time won’t actually charge it beyond its rated capacity.
When lithium-ion batteries and lithium polymer batteries reach 100% charge, the laptop will stop charging and run directly off the power cable. Once the charge level of the battery drops a bit it will recharge itself to 100% again.
This process will repeat itself constantly until you take the laptop off from charging. Though just because your laptop battery won’t overcharge still doesn’t mean you should leave it plugged in all the time.
Fully Discharging
If you let your laptop fully discharge for an extended period of time then it can cause permanent damage to the battery, and it might never be able to hold a charge again.
To put the definition of full discharge in more technical terms. It is when the battery runs out of power to the point where the chemical process in the battery cannot be fully reversed by charging, effectively rendering your laptop battery useless.
Battery Degradation
No matter how much you try to take care of your battery, overtime the cells within it will start to degrade and you will start noticing a considerable difference in the laptop battery’s capacity.
There are three main things that affect the lifespan of a laptop battery. These include.
- Charge/Discharge Cycle & Voltage Levels
- High Temperatures
Studies for how these factors affect battery performance and lifespan were conducted by Battery University. To learn about any information pertaining to batteries, just head on over to their website.
Charge/Discharge Cycle & Voltage Levels
A charge or discharge cycle can be defined as “the process of charging a rechargeable battery and discharging it as required into a load”.
This number is usually used to define how long a battery is going to last. When lithium-ion batteries, the most common laptop batteries are charged to 100% capacity they possess 4.2 volts per cell with an estimated 300-500 charge cycles lifespan.
So think of it like this, when your battery is nearly fully charged it has more voltage per cell, but as you use the laptop and the battery percentage decreases. The volts per cell will also gradually decrease.
Below is a chart that details how many charge cycles you can expect to get out of a battery if you only charge it to a certain percent.
For every 0.1 Volts drop below the maximum 4.2 Volts per cell that lithium-ion supports you can nearly double the charge cycle.
As you can see from the chart if you only charge your battery to around 80% your battery can withstand 600-1000 charge cycles as compared to just 300-500 if you kept it at a 100% all the time. This is why you often hear people telling you to only charge your electronics to 80% battery capacity.
So if you left your laptop plugged in charging all the time, it would significantly reduce the number of charge cycles the battery can support. You could start seeing battery degradation before the laptop is even a year old.
We would recommend only charging it to around 80% and then using it on battery power from then onward. Also be sure to not let the battery level drop too low before charging as that can have adverse effects as well.
High Temperatures
Another test conducted by battery university stated that high temperatures can also have a negative effect on your laptops battery. Any temperatures higher than 30C will without a doubt damage your battery.
From tests conducted by Battery University, if you store your battery charged at 100% at a temperature of over 40C for one year. The maximum battery capacity will drop to just 65%.
When you leave your laptop plugged in all the time, it can produce quite a considerable amount of heat. Those high temperatures are as we have clearly seen not good for your batteries internals.
If you plan to leave your laptop stored for a prolonged period of time it’s best if you take the battery out from the casing if possible. Always store it in a cool area where temperatures don’t exceed 30C.
So if you have a habit of leaving your laptop plugged in all the time, using it outside on a hot sunny day, or leaving it inside a hot car. It’s best if you stop doing that.
What If I Have A Gaming Laptop?
If you own a gaming laptop then you’ll know that in order to get the maximum performance out of your machine you will need to have the power cord plugged in all the time.
Most batteries that come equipped in gaming laptops just can’t output the power needed to run the CPU and GPU at max tilt.
Sadly, there is no workaround for that, if you can remove your laptop battery and just run it directly on the power adapter that would be a good option. Though as most modern gaming laptops don’t have removable batteries this really can’t work for most of you.
However as most of the current will be going to powering the internal components your battery is only going to be trickle charging at best. So it should be okay for short periods of time.
Get A Battery Report
If you want to know how your charging habits have affected the battery life of your laptop. You can run a battery health report check inside Windows command prompt. You won’t even need an external software.
Step 1: Click on the Search Bar near the Windows Start Menu button
Step 2: Type in “CMD”
Step 3: Right Click on Command Prompt.
Step 4: Click on “Run as Administrator”
Step 5: You will be presented with a layout like this.
Step 6: Type in the command “powercfg /batteryreport”
Step 7: Once finished it should give you the URL of where the battery report is saved. Copy it from CMD.
Step 8: Open File Explorer and paste it in the file path section
Step 9: A new tab will open in your browser with the battery report.
Step 10: The section Installed Batteries will give you info on your original and current battery capacity.
Step 11: The section Recent Usage gives you power stats over the last 3 days.
Step 12: The section Battery Capacity history gives you information on how the capacity has decreased overtime.
Step 13: The section Battery Life Estimates gives you an estimated battery life based on previous battery life drain recordings.
Conclusion
So after reading this guide, you should know all there is know about what happens when you leave your laptop plugged in charging all the time, and the consequences that can come along with it.
If you feel we missed anything out be sure to tell us by leaving a comment down below. Also feel free to tell us whether you use your laptop plugged in charging all the time or not, and how it has affected your battery performance and capacity.
Good article. The battery controversy has been going on forever. Thanks for
writing a clear and concise article on the subject!
Jim
Thank you this article has been a great help, as an 83yr old with little IT knowledge it has given me enough information to also help me charge up my golf trolley battery with best practice!
Nice article…thanks!
I understand the affect of temperature on the battery degradation.
However, what is the connection between this article and the laptop manufacturer offering a BIOS option to “optimize” battery life if the laptop is kept plugged in? I think they recommend small lifecycles like 95-100% or 75-8%
Since this is such an issue, why don’t PC makers created an option for “Maximimize battery life” for the large number of users that use their laptop as a desktop? A simple option option with the battery icon could automatically set charging between 20% and 58% or what ever levels optimize the battery life. Obviously there should be an option to charge to 100% for when the laptop will be mobile.
So based on your article, I don’t see any specific recommendations. To maximize batter life, should users unplug batter and wait until it is at 20% and then recharge to 58% or some other strategy? Obviously any manual operations like this will result in accidental full discharges if 100% attention is not kept on the batter indicator. I was hoping for some actual plans in your article.
“When lithium-ion batteries and lithium polymer batteries reach 100% charge, the laptop will stop charging and run directly off the power cable. ”
I want to know what is the electrical components called that actuates this switch between pulling power from the battery to pulling from the power cable?
This still leaves things up in air. I guess I will turn it off and then have to turn on earlier then when I am going to use it allow for updates!
This article has misconstrued the data and drawn incorrect conclusions and provided poor advice. Leaving a laptop plugged in doesn’t constitute a 100% charge cycle. The battery will charge to 100% and stay there, the laptop will then run from AC power all day every day until unplugged. So if you plugged it in and it recharged to 100% and then left it plugged in for 365 days and assuming it doesn’t discharge then there is only 1 recharge out of 500 recharges 1/500*100% = 0.2% of its life expired. Compare this with taking it off charge 3 times daily when it reaches 80% charge = ~3*365/1000*100% = 110% of its life expired. Leave your laptop on charge all the time unless you absolutely need to be portable with it! And stop reading stupid articles.
This is the best reply to this article. I have been using my laptop for last five years. My PC usually remains plugged. And, my laptop’s battery health is still the same as it was when I purchased it. I don’t know physics, but in my experience, keeping a laptop plugged doesn’t affect battery health at all.
With 2 laptops I always did what you are saying and after a couple of years the battery inside starts to swell and you see this when your keypad is bulging in the middle. Research says the main cause of this is having the charger powering the computer and charging the battery all the time maintaining 100%. If the pressure overpowers the thin covering the battery explodes and fries the computer and releases bad stuff in your room. With older laptops that had a CD drive and the battery connected externally on the bottom in a rigid case this couldn’t happen.
My Surface Pro laptop is connected to a docking station, which includes a large monitor and external hard drives. Every time I unplug to run on battery, I lose the connection to the docking station (and peripherals) AND I need to reorganize my desktop view on the monitor when I plug into AC.
Any ideas for me?
Jim – this is good work. The article is useful, relevant, and accurate. My only question is that I recently received a new HP laptop for my wife and charged it to 100% before evening opening it. I intend to “clone” her other laptop image to this new one (MS makes that easy these days with 1-drive), but she is still using her old one for urgent business. I don’t want to open and initialize her account on the new one until hers is shut down. I have unplugged the charger from her new laptop, however, I have yet to turn it on. Is just sitting there for several days, without being turned on yet and with the battery at 100%, doing any harm to the new laptop battery?
Also – just FYI – we are typically leaving the battery charge level (idle after use) between 50 and 80% capacity, and recharging it to ~80% when it falls to ~45%. I have learned that Lithium ion batteries have a better mortality if maintained in this range (also recommended by Tesla, and Samsung for smart phones). Let me know if you agree ?
Thank you for your time, and your consideration.
Sincerely,
Richard