New battery installed but drains after four days

Hi and thanks for using 2CarPros.

Either you have a bad alternator or component within the charging system or an electrical draw. I am going to provide links that discuss how to test if the alternator is working as well as how to check for an electrical draw. I noted that you indicated little knowledge, so I will also include links showing how to check electrical components using basic tools. First, here is the testing equipment:

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-check-wiring

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Here are the two tests I need you to follow. They are not too difficult and I'll be here to help if needed.

https://www.2carpros.com/articles/how-to-check-a-car-alternator

https://www.2carpros.com/articles/car-battery-dead-overnight

Let me know if this helps or if you have other questions. One last thought before you start. Make sure the battery terminals are clean and tight.

Take care,
Joe