I’ve had issues with my 1999 Maxima not starting on its own. When I first got it used I changed the alternator and the starter. It ran fine for about 2 years until it stopped starting on its own. I replaced the battery every time I had this issue but I was doing it too often. I decided to invest in a portable jumper and my car starts when I jump it , but when I turn the car off it doesn’t start on its own.

 

Aftermarket alternators usually are a temporary solution for the 4th Gem maximas. I went through several before I went back to the original Hitachi in my 1999 and it was rebuilt/re-manufactured by HITACHI.

You will need a volt meter or DMM to see what voltage you have with the car running hooked up to the battery. It should be somewhere around 14.2 volts. That's what is needed to keep the battery healthy.

A healthy battery is usually around 13.2 volts with no draw. If your actual measurements aren't there, you now know what to replace. If the numbers are where they are supposed to be, you have a voltage drain somewhere like a light that stays on. Or a short, but these usually cause a fuse to fail.

AND PUT YOUR LOCATION if you want to help yourself.