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How To: Calibrate Your Laptop’s Battery And Why You Should Do It

Updated on January 13, 2014
How to perform laptop battery calibration
How to perform laptop battery calibration | Source
Laptop battery
Laptop battery | Source

How modern Lithium-based batteries work

Old nickel-based batteries had the memory effect, meaning if you repeatedly did only shallow discharges the battery would “remember” this, resulting in decreased capacity. But this is not true for Lithium-based batteries; the kind modern laptops are equipped with. In fact only performing full discharges can harm them.

Lithium batteries don’t do well with extremes: meaning if you do a very small discharge to 90% or a big one to 0%. The optimal discharge for a Lithium-based battery would be to 50%. I know this isn’t possible to accomplish every time, but do try to plug in your laptop once the battery drops to 20-30%.

There’s also a myth stating you shouldn’t leave the battery in the laptop while A/C is plugged in. Actually, the fact it’s plugged in while it’s fully charged doesn’t harm the battery. Once the battery is charged to 100% it stops receiving charging energy. Instead your laptop’s power supply will receive it directly.

There is one problem though: if your laptop gets too hot while the battery is inside, that can harm it. So you either make sure the laptop has proper ventilation (using a cooling pad is a good idea) or you remove the battery while you’re using the laptop plugged in. Extreme heat is the no. 1 enemy of batteries.

Laptop battery level
Laptop battery level

What is battery calibration?

Modern batteries are “smart”, they can tell us how much time we have until they are completely discharged. But after lots of shallow discharges these readings become inaccurate. This may lead to an unexpected shutdown or sleep while Windows reported there was still 30% battery power left just moments ago. As we discussed above, Lithium-based batteries don’t do well with repeated full discharges, so calibration is required to make sure battery readings are accurate.

Battery calibration is a very simple concept: all you have to do is let the battery run from 100% to 0% and then charge it back to 100% again. This will calibrate the battery power meter. While doing full discharge regularly can harm the battery, doing a calibration every 2-3 months can make sure you are aware of your true battery energy levels at all time to prevent full discharges.

Laptop charging
Laptop charging | Source

How to perform battery calibration manually

There are utilities and even a BIOS feature that you can use to calibrate your laptop’s battery, but the most simple, straightforward way is to do it manually. Here’s what you need to do:

Step 1

Charge your laptop battery to 100%.

Step 2

Keep your laptop plugged in (you can use it normally) for about 2 hours. This will allow the battery to cool after the charging process.

Step 3 - Windows Power Options
Step 3 - Windows Power Options

Step 3

Go to Start and type “power” in the search box and select "Power Options" or go to Control Panel - Hardware and Sound - Power Options. For your current power plan (the one that is checked) select “Change plan settings”.

Step 3 - Change Advanced Power Settings
Step 3 - Change Advanced Power Settings

Click on “Change advanced power settings”.

Step 3 - Windows Advanced Power Options
Step 3 - Windows Advanced Power Options

Now you need to make sure your laptop sleeps or hibernates at 5% battery. For that you need to go the “Battery” and for “Critical Battery Action” – “On Battery” select Sleep or Hibernate. For “Critical Battery Level” select “5%”.

Step 4

Now you can unplug your computer and use it until it sleeps or hibernates. If you want to discharge the battery while you’re not using it you have to make sure it won’t turn off the display, hibernate or sleep while it’s idle. That will prevent the battery from discharging correctly.

Step 5

After your computer shuts down, don’t use for 5 hours or so.

Step 6

Plug in your laptop and let the battery fully recharge. You can use it normally during the charge process. That’s it! You successfully calibrated your laptop battery.

Because you have to let the laptop stay for at least 5 hours after the discharge I recommend you do this before bedtime or another time when you know you don’t need to use your laptop. Also, after the calibration make sure you restore your usual power plan settings and power options.


Battery management software

I hate to say it, but this type of software is not getting the appreciation it deserves. From all the utilities out there, the one I heartily recommend is BatteryCare. It’s a free program that can help you in several ways to manage and take good care of your laptop’s battery.

Firstly, BatteryCare monitors the number of discharge cycles. Even if you used 25% of the battery for 4 times, the application counts it as 1 full discharge cycle. After a certain number of discharge cycles (30 is the default) the program will remind you battery calibration is needed.

BatteryCare gives you detailed battery information such as designed capacity, total capacity (like I said, with age and use, the battery capacity slowly becomes smaller), wear level and other useful data. It also monitors and displays CPU and HDD temperatures so you know when your laptop is getting too hot.

Another important feature of BatteryCare is power plan switching with some extra settings compared to the default Windows ones. Besides choosing which power plans you want the laptop to use while on battery you also have the option to disable some battery-draining Windows features (Aero, Sidebar/Gadgets) and services.

This is a lightweight, but very useful program that helps you remember when its time to calibrate your laptop's battery based on how frequently you use it (the number of discharge cycles), which is truly the most accurate solution. Because it's such a small application BatteryCare download and installation are done in a matter of minutes, plus it runs quietly in the system tray counting your discharge cycles and waiting for your instructions.

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      Tim 2 years ago

      That loud fan is definite sign that there hasn't been any caelning maintenance performed on your sister's old laptop. When dust builds up on the fan blades and other locations inside the laptop, it will cause the computer to overheat and get really hot, and possibly shut down to protect itself. You can usually use canned air ( available most places where computers and computer accessories are sold ) to blow air into the laptops vents on the sides, and force the dust/dirt out of a vent on the opposite side. If this maintenance isn't done regularly ( every few months ) then the dust begins to build up on the fan blades and throw it out of balance which usually makes it very noisy. This seems to be your problem. If you don't have any experience in opening up a laptop, I'd suggest either asking a friend that has this experience ( and proper tools ) for some help, or take it to a computer repair shop for the maintenance. It will cost you some money to have a repair shop do the work, but if you just use the canned air at a regular interval, you won't need to have the shop do this again. The fan blades are delicate and need to be treated with care if you or a friend decide to do the caelning yourselves. Sometimes, depending on the brand of laptop, the fan is difficult to get to, so be wary of this. If you do take it to a computer repair shop, have them test the battery and charger while they have it to see if there's a problem with either.