Inaccurate Battery Charge Reading (?)

I'm attempting to discharge my battery.

Before my trial, I'd already had it at 1% charge. I'd left it open for over 50 mins now; despite the image saying it's got 2 mins remaining.

Prior to discharging, I've set power mode at best performance to assure that it gets drained quickly.

However, it's yet to fall to 0%.

Over the last week, I've been under the assumption that there's something wrong with my battery — although in the BIOS it displays "normal".

Perhaps my battery is fine and the charge's just being read inaccurately?

Please educate me as to how I can clarify.