Flickering lights

[Desotodude]

My first problem started out replacing the battery. Alternator kept draining the new battery. Replaced the alternator. Had to keep jumping the car to get it to start after this. Cleaned fuse panel and it started working ok. Now the lights are flickering outside and then flip to doing it in the interior. Still have problem starting the car but not having to jump it like before. Mileage is just over 73,000 miles for a 2015 1.8l. I have a diagnostic machine but still trying to learn how it operates so I can't get any codes to work with. I am retired and on limited income so I do most of the work myself. Also replaced the starter around six months ago.

 

[JTee2017]

Check out the negative battery cable and other grounds to the engine and chassis. Loosen, clean down to bare metal, wire brush the ends, and apply a thin coat of grease before fastening them down. Clean the battery terminal cable ends.
One thing that happens sometimes. .. is the negative battery terminal gets corrosion down inside just past where it is crimped onto the cable connector clamp. You may not see it, but I've seen cables that were literally eaten down to only a few threads of copper wire under the cable insulation at the end hear the battery.