Why did my Windows 10 PC shut down (automatically), saying that the battery is low when it showed 72% just seconds before?

Question

Recently, at least twice, my Windows 10 PC shut down automatically, saying that the battery had drained. But it wasn't even a minute before I saw it when it was 72%. I opened a few apps, a heavy code editor, Discord and Google Chrome. It was lagging as I'd opened them together and was waiting for them to load. After a few seconds, my PC shut down.

I don't think the code editor (PyCharm) consumed too much power or anything. How is it possible? This happened just yesterday, too, and it was some 54% battery then. The same thing happened, but I don't think I had many (I usually have five apps open simultaneously, at maximum) apps open then.

After plugging the PC and immediately powering it on, it shows just 6% battery. Yesterday (when it was 54%), after a few minutes, it was 12%. So, it had really drained somehow. But how? Or is it some kind of serious bug? I don't understand.

Please don't suggest it might've been due to high brightness, too many apps open together, etc. It had really drained in minutes, if not, seconds, in front of my eyes.

Windows has been suggesting I switch to Windows 11 (I'm currently using Windows 10 and prefer to continue using Windows 10). Is this another dirty trick Microsoft is using?

Answer 1

There are two options: the battery is faulty, or the power conversion circuitry in your laptop is faulty.

1. Batteries can develop faults where they work fine under light load, but a sudden or sustained heavy load can cause them to fail. Essentially the chemical reactions within the battery cannot move fast enough to supply power, the battery voltage drops below what the system needs to function and the whole thing falls over.

2. One or more components have weakened over time in your battery supply chain and can no longer supply peak power.

Option 1 is far more likely. Batteries are very rarely "perfect" due to them being more about chemistry and reversible reactions to store and release energy. Most laptops make batteries easy to replace.

This option also seems more likely given that you state that it happened when you launched multiple programs all at the same time. Each program will be heavily using the disk to grab their files, will be using the CPU heavily to do their loading and setup, and may even be tweaking the GPU into high power modes to set up display data. All of that would combine to make for a sudden very heavy load which would expose a weakness in some components.

In the first instance you should replace the battery, preferably with one from your manufacturer.

Answer 2

If it was not fully charged the previous time it's possible that it wasn't actually 72%, you'll often see when charging that the percentage starts going up quickly but as it goes up it gets slower and slower and can stay at a higher percentage alot longer than it did at a lower percentage, if it wasnt fully charged the previous time it can lose the supposed high percentage charge very quickly.