Is your iPhone loaded with free apps? You know, apps like Facebook? Well, mobile advertising has recently taken off and that means that those free apps now come loaded with ads. While ads running at the bottom of your app screen may not bother you, they are bothering your phone, it seems. Researchers at the University of Perdue (originally reported by Cult of Mac) have discovered that nearly 75% of your iPhones energy is zapped by in ad apps.

How can mobile apps take up so much of your phone’s energy? The answer here is really quite simple. In app ads don’t just display annoying information. These ads are also targeting you as you play games and read what’s posted on your friend’s Facebook wall. Using GPS location information, apps target where you are located and then provide you with a smattering of ads that are supposed to target your specific demographic or area. The result is a drained iPhone battery that can really be quite annoying.

How to Stop Draining Your Battery

Cult of Mac reports that an iPhone battery can be drained in as little as 90 minutes thanks to some in-app ads. For now, most of the apps responsible for life-sucking ads are free apps. So, one thing that you can do is to look for the paid version of the app that you want to use and spend the $1-$2 for that app. Another thing that you can do is to simply avoid opening up those free apps on a frequent basis.

For example, if you’ve ever been stuck waiting for an appointment or waiting in line, you might have been tempted to open up your Facebook app. You then might have noticed that your battery becomes lower and lower the longer you look at that app. If you just skip opening up the app to begin with (and reserve looking at this app until you are near an outlet and don’t need to rely on your battery life), you won’t face any drainage problems.

Paid Apps Might Soon Include Ads Too

If free app developers can rake in revenue by selling ad space, paid app developers might very well start doing the same thing. For now, only those free apps will drain your batter due to in app ads, but this might change in the long run. In the very near future, apps of all kinds will start running ads and then the only thing to do will be to wait for some other developer to figure out a way to by pass ads using a different app that, hopefully, doesn’t contain any ads. Mobile advertising is really picking up this year and its simple to see why – after all, how many times have you clicked on an in app ad thinking it was part of the app?

In any case, if you want your iPhone battery to last a bit longer, just skip those free apps for now. I know it’s hard to resist opening up Facebook or seeing how your favorite free Angry Bird friends are doing, but you’ll have to decide between a bit of boredom or a phone that won’t last longer than ninety minutes.