Sudden decrease of laptop battery capacity

Question

Hello! I recently bought a new laptop battery last April. One day I noticed that my battery discharges faster than usual. After checking the battery report, it looks like the battery capacity (see second column) has decreased by 3,029 mWh on June 21st to 22nd (from 32,560 to 29,300 mWh). May I know what can be the probable cause of this? I tried calibrating the battery today, June 28th, and the capacity decreased down to 29,280 mWh. Is my battery defective, or is this normal on fairly new batteries?

Answer 1

Hi, my name is Neil, I'm an independent adviser and a Windows 10 user like you.

Although it is normal for battery capacity to decrease over time, I would run a 'manual' calibration. By that I mean let your battery drain right down until it is no longer capable of powering your laptop.

Then plug in the power lead and let the battery fully charge to maximum (without using the computer). So, plug it in until it charges 100%.

Then turn on your computer and run a new check on the capacity. Often software battery calibrations (if that's what you did) aren't as accurate as completely power cycling the battery down to zero and back up to full charge.

Even those batteries with 'no memory effect' do actually have a small memory effect that can snip away at your capacity results. A good battery drain and recharge usually sorts out those out.

The capacity drain may level out as the battery is used and the drops in capacity will still occur, but will decrease in size each time. It's one of those things that if you focus on it, you will always see it dropping and might worry something is wrong, but it is normal for a battery to drop quite a bit during a year, so it will drop more and more over the coming months.

Totally depending on use, some people consider a battery needs to be replaced every 2 years, whilst the average says 3 - 4 years. If you're using your laptop on battery all the time, then expect it to lose capacity quickly and need replacing in as little as 2 years. You will obviously see dramatic drops in capacity month by month as well.

I hope this answers your question.

Kindest regards,

Neil

Answer 2

I wouldn't be overly concerned if it now plateaus at this level and only drops incrementally. There is always some larger mWh drops off a new battery once it's been in use for a few months. I don't think yours is abnormal at all. I think it probably looks worse because it has dropped from the 30,000 mWh range to the 29,000 mWh range.

Say, if it had dropped from 36,500 mWh to 33,500 mWh then it doesn't look as bad as your still in that 30,000 mWh range. But because yours has dropped down to the 29,000 mWh range there is a psychological trigger there making the drop seem more dramatic than it actually is.

There is an excellent guide from How To Geek on how to really calibrate your battery thoroughly. I would take at look at this and you'll get a much more accurate picture of your battery's health: https://www.howtogeek.com/172271/how-to-calibra...

I hope this all helps!

Kindest regards,

Neil

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Answer 3

Hi! I did the 'manual' calibration just as you said: discharge completely then recharge fully.

Is it normal for it to drop by >3,000 mWh over the course of a couple of months? Thanks!