The Battery and Brake light came up together. Not sure what is the cause

alternator is bad and your car will die in the middle of the road or freeway. your battery might also be bad see if your battery has many months to live before you buy another one. have alternator replace asap... before accident happen. if you dont believe me ask the mechanic. he will charge you a lot of money but your safe. same answer he will give you after so many b/s of troubleshooting. the brake light mostly will come on when the alternator is in-op. good luck with the mechanic. find an honest one.

Go to a Mitsu specialist or an auto electric shop. Here's a directory link for you: https://repairpal.com/mitsubishi-repair-in-houston-texas

I had the same light come on together as you. I took it to Advance and check the battery charge, it was low so they gave me a new battery in exchange for the other one. So then I had a fully charged battery, then I took it to the mechanic and he said it was the alternator. He changed it and then the car ran just fine. The lights went away also.

Mine was the alternator.