Can anybody tell me what is wrong with my 2009 Lancer Sport?
 

2009 Mitsubishi Lancer sport, with Rockford Fosgate sound system.

https://youtu.be/vXe_JmqcRgM
https://youtu.be/SFfCjox9kV8

Above are a couple of short videos showing the issues I am currently having with my Lancer. Be sure to check the description of the YouTube videos as there are additional details about the issue.

About three months ago I ran into a dead battery, and I thought it was just that. I replaced set battery at approximately four weeks later I again came across a dead battery. I had the battery tested and it failed, so I again had it replaced. 2 weeks later the battery was dead again and I had the alternator tested but you're different shops in the mean time. The alternator passed both times.

Yesterday I walked out to start my car, and it started showing the symptoms outlined in the videos. Is there anybody out there that I can explain what could cause such an issue?

The only thing I can think of is there's a short in a wire somewhere.