The battery and alternator are two separate animals.
Either one can go bad, or even new ones can be defective, this goes for any part (so never exclude the possibility that the "new" stuff did/ or should have fixed your problem).
Most likely you did fix your problem with the new battery.
Want to be absolutely sure?
You can obtain a cheap, but great ($5.00) digital voltmeter at "Harbor Freight" or at auto part stores for a bit more.
This is a tool in which you can use for your car or home for many, many tests, it's not a one time user! See You tube.
For now, I got you a "Repair Guide" from the top right of our pages, here it is:
https://www.2carpros.com/articles/how-to-check-a-car-alternator
This will explain and show you how to test your alternator.
Return here and let us know your results.
The Medic
Saturday, November 16th, 2019 AT 3:06 PM