I bought a laptop recently. It has nothing to write home about. However, its battery is acting bit funny. It keeps draining even when it is disconnected from the main. It turns out this is normal for new laptops. New laptops have a "useful" feature called "Power-off USB charging", which allows devices like phones to use the laptops's battery as a powerbank. To do this, the laptop is essentially "always on", which slowly drains the battery.
I don't know about others, but I personally dislike this feature. With this feature enabled, if I don't use my laptop for a a day or two while it is discconected from the main, the battery goes flat. This was not the case with my old laptop. Although its battery would still go flat eventually, it happens at a much, much slower rate.
Luckily, this feature can be turned off, though you may need to do a bit of "hunting"/research as I did. My laptop is an Acer. Firstly, some geniuses over at Acer decided this feature should be hidden in BIOS. To reveal the hidden options, you need to press the CTRL+S when you are in the bios. Then, look for a very obvious option called "TBT Wake from S4 Support", and turned it off. It is so obvious, isn't it?
As a final step, launch "Quick Access" as an admin, and then disable "Power-off USB charging" from there.
My laptop battery now behaves like it should be.
While we are on the topic of hidden options. The reason I found the hidden menu was that I had reset my laptop BIOS, after which Windows could no longer find my NVMe drive. It turned out that the reset had reset re-eabled the Intel VMD feature. With this enabled, Windows requires a special driver to "see" the drive. Once I found the option, and turned it back off, Windows booted perfectly.