Studies show that low battery life may lead to price surges.

Ever had your smartphone warning you about low battery when you’re out and about? Well, we know that’s most definitely a yes, but did you know that this could be used to track your online movement across various sites?

As bizarre and disturbing as it may sound, the software that enables your battery and you to load a website on your phone can be used to see what you are actually browsing. That’s according to Steven Englehardt and Arvind Narayanan both of Princeton University, who have been doing a research on online tracking by ad tech companies.

On top of discussing various privacy-related issues, the duo noted how companies can turn websites visitors’ outstanding battery life into device fingerprints. Companies can gain access to information about their consumers’ battery life using code inside of HTML5, which is the up-to-date version of code used in mobile web content.

According to the researchers; “Companies can combine the seconds left in the battery with the remaining percentage of battery life to get the details about website visitors.”

For instance, when you visit a sports website and your phone has low battery levels, the site will pick this up and direct you to a less complicated version of the website so as to conserve your battery. In using your phone’s battery life to obtain the device’s fingerprints, these companies could possibly use this information to manipulate you into making decisions you wouldn’t normally make, or know that you have limited time and pressure you into paying more for something.

So next time you’re on low battery, just watch your back.