Why do "closed" apps drain the battery?

[codyoehl]

Why do apps on Android drain battery life after you close them
I notice it with a lot of apps, I use them and the battery percentage goes up, and it takes forever for it to go back down
Like earlier I was watching you tube videos and hours later, YouTube is still draining 15% of my battery

Posted via Android Central App with my Samsung Galaxy S5

 

[B. Diddy]

re: Why do "closed" apps drain the battery?

It doesn't mean the app is constantly using 15% of battery. It means that of the total battery used so far, roughly 15% was used by YouTube. If you weren't doing much since you stopped using YouTube, the percentage isn't going to change a lot, since YouTube does use a fair amount of battery (due to the screen being on the whole time you're using it).