2010 Mitsubishi Galant new battery messing up

About a month ago my car would not start. I didn’t jump it off at first because it eventually would come on. After a couple of days of that, it died completely and I jumped it. Took a little bit to come on but went straight to Walmart and bought a brand new battery. As soon as I changed the battery it worked with no problems. That was about a month ago. I’ve had no problems. Today after I got out of my car I tried to lock it and it would not lock so I tried to start it and it would not turn over at all. It’s been about an hour and still will not come on. I don’t know what’s wrong? And, I have been having trouble with my red brake light. It will randomly come on then off. Mostly when I’m stopped and try to go again. It will act like it’s not going to accelerate and feels like my brakes are locking and the light will come on. Is this my alternator? Or something else? I just don’t know why my new battery would work for a whole month if the alternator was bad…

You have a few things going on with this car that is draining your battery. I suspect you don’t have the tools or knowledge to diagnose this. I suggest you take it to an independent repair shop and pay for a proper diagnosis.

I suspect you have a couple of probably unrelated problems. The first may or may not have been your battery. Unless you tested it there’s no way to be sure if it was the battery or the alternator.
Second, when you say your “red brake light,” are you referring to the brake indicator on the dash? If so, it’s telling you there’s a problem and that the brakes require service. Have a real mechanic who can actually see the car diagnose the problem.

Sounds like you are experiencing an intermittent charging system failure, has the battery light also been illuminating? If the alternator is failing intermittently the battery will become discharged and the engine will not start.

+1. As long as your brake fluid level is ok, I would start here. When the charging system isn’t working correctly, it can make other lights come on erroneously. @Whitney-12 If you don’t have the tools or know how to test any of this on your own, I would definitely suggest that you take this to a mechanic for diagnosis as it is definitely possible that you have issues in both the electrical and braking systems