How to Check Laptop Battery Health Status

Should You Leave Your Laptop Plugged in All the Time? The same question from me every time I leave the office and left my business laptop there on my desk. The answer actually a simple YES or NO.

In a modern laptop, there’s a new improvement for battery treatment. Having a battery fully charged and the laptop plugged in is not harmful, because as soon as the charge level reaches 100% the battery stops receiving charging energy and this energy is bypassed directly to the power supply system of the laptop (- batterycare.net).

All laptop batteries are built to handle a certain number of charge cycles, usually somewhere around 500 full cycles and sometimes more. Essentially, a charge cycle equals one full discharge down to zero percent and then a recharge back up to 100 percent. A discharge down to 50 percent and then back to 100 percent would equal half a cycle. Over time, each charge cycle decreases a battery’s capacity from its design specifications, meaning that the fewer times you drain it, the longer the battery last — all other things being equal (- digitaltrends.com).

There are two main types of battery used in laptops: Lithium-ion and Lithium-polymer. Although they are different technologies, they function in broadly the same way, with power being created by the movement of electrons. This flow also helps to keep the battery healthy.

For both types of batteries, the following statements are true (for modern laptops):

  • A battery cannot be overcharged. There’s no danger of a battery being overcharged if you leave it plugged in all the time. As soon as it hits 100%, it will cease charging and won’t start again until the voltage falls below a certain level.
  • Fully discharging a battery will damage it. Having a battery fully discharged for an extended period can put it into a deep discharge state, from which it might never recover.

So, based on this, do we conclude that you should simply leave your laptop plugged in all the time? Not quite.

Lithium-ion batteries charge to 4.20V/cell, which amounts to 100% of its capacity. At this level, the battery will have a lifespan of 300-500 discharge cycles. Every 0.10V/cell reduction in the charge doubles the number of discharge cycles until the optimum is reached: 3.92V/cell, with 2400-4000 discharge cycles. Unfortunately, at this level, the battery is only 58% charged, so the runtime will be little more than half of a fully-charged battery.

Should You Remove The Battery? If heat is such a danger, it begs another question. Should you remove the battery altogether when using your laptop on AC power? Obviously, this isn’t possible on the growing number of laptops that sport sealed batteries. Where they are replaceable, the answer seems to vary from one manufacturer to the next. Acer, for instance, suggests removing the battery at all times. When Apple produced laptops with removable batteries, it advised against ever taking them out.

Unfortunately, my battery seems non-removable on my personal Dell laptop. So, it’s better to check the battery health status now. FYI, my new Dell laptop is 6 months old, and the charger is always plugged-in.

Here’s how you check the battery health status:

  1. I’m using Windows 10, so it may apply only if you use the same OS as me.
  2. Open Windows Explorer, Go to C:\Windows\System32 and find cmd.exe there.
  3. Right click on cmd.exe and Run As Administrator
  4. Then type: cd %userprofile%/Desktop
  5. Now type: powercfg -energy
  6. Command Prompt will start generating a test, you will get a window like this,
  7. Wait for a minute then the result will appear. I have 4 errors, 13 warnings, and 45 informational regarding system power management that affects my battery health status
  8. Open your Desktop and find energy-report.html, open it with your default browser to see the result.
  9. Go to the half of the page and find information like this,
  10. The most important thing is Design Capacity and Last Full Charge info. You can use it to calculate your battery health status. Do the calculation like this, (Last Full Charge) : (Design Capacity) x 100 = Result
  11. Mine will be like this: (38,714 : 41,998) x 100 = 92.18%

Hope this helps, and my suggestion is to avoid unplug the charger everytime you turn off the laptop, except if you bring your laptop with you (mobility).

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