My laptop battery discharged in sleep mode?

My laptop computer is an Acer Aspire M5-583P-6428 touch screen laptop computer. Its specs are as follows:

Intel i5-4200u Quad-Core Processor

Intel HD 4400 Integrated Graphics

500GB hard drive (spinning-disk)

3560 mAh 4-cell lithium polymer battery, advertised up to 6.5 hours battery life (though I have seen it do much better)

8GB DDR3 RAM (~7.66 usable)

Windows 8.1 Update 1

A couple times lately, I have noticed something strange occurring.

What happens is this. My computer will be fully charged, and I'll put it into sleep mode and put it up, sometimes for a day or more at a time, because parents (though that doesn't matter at the moment).

What I've had happen twice to me now is this. When I get to school in the morning, I'll open up my computer and attempt to turn it on. The battery light will blink orange at me a couple times, and then do nothing; I'm sure this is the indication that the battery has died, but it's most likely just that it has only 5% charge remaining.

I've had my laptop since August 8, 2013, and this has only happened twice - Once this morning (December 8th at the time of writing this), and once before, some weeks ago. I'm not sure whether to think this is just a result of being in Sleep mode for days at a time, or if my computer is acting up again.

Could someone please provide me with some insight to this issue and/or assist me in reaching a solution?

NOTE: For those who are contemplating criticism for how I use Sleep mode, please know that I only do so because of its convenience; I usually have multiple important tabs open in Google Chrome, and also prefer to start right back where I left off in my programming projects rather than try to remember what exactly I was working on.

Answer

Sleep mode uses battery if not a whole lot of it. Some motherboards will also "wake" the laptop in the presence of a signal from some connected device. As an example, I have a laptop that will wake up if I have a wireless mouse dongle plugged in and don't turn off the mouse before putting it to sleep; the very act of moving the mouse signals a wake-up.

So, the best explanation is that your laptop woke up from sleep mode and drained its battery. Windows is configured by default to automatically put laptops in hibernate at a certain battery level (I believe 1%). You can verfy this by checking the event logs for events in the time you expected it to be asleep.

Edit: As an aside, use Hibernate. It's a bit slower to boot up but these wake problems will go away.