battery drains overnight after a jump new battery in car altenator a possibility

If your battery is draining over night with a new battery chances are its not your alternator. it sounds more like you have a draw from the battery. any aftermarket electronics can cause this issue. best way to check is when the battery is charged with everything off use an ammeter. if there is any amperage going from the battery then you have something left one drawing power and draining your battery

Do exactly as Austin said and to go further pull fuses one at a time till it quits

You need to check for a draw. check all ground wires. this is not a alternator problem

All of you are wrong. I own a 97 lumina ls. I had the EXACT same problem. It was my alternator ground wire. They have a tendency to vibrate loose if not completely tightened. If put a latex locknut on mine and fixed the problem.

#1 latex is a rubber which makes it NON-conductive. #2 the alternators shell is a ground. There is no ground strap it grounds directly through the housing to the bracket to the engine.

Right . Yes latex is nonconductive. Thats why I chose that style locknut. It was arcing and it prevents a short to the block. But the ground strap comes off the stud in the case and into the block. Loose stud or nut, Instant battery draw. Because of through air transmission, the battery is beint drawn down and the amperage necessary to recharge is lost. I know the tech. Degrees in auto tech and aviaion maintenance.

Most of the time, like you said, check ALL connections. Then start pulling fuses and relays. Aftermarket equipment just increases load

I had a 2001 Chevy Lumina and the parasited draw was from the radio I had installed. It was still running even with keys out. Battery would last two days when jumped then die. This is a slow drain. Some take up to a week to kill your battery. Had radio wiring redid and no more draw.

My battery drain overnight on a 1999 Chevy lumina

So I put a new altinator in my car because it wassanr staying charged and it still won't everything is hooked up properly and belt is on it any ideas

I went thru several alternators on my 93 lumina. My mechanic said there was a 3 amp draw from something - he thought in the passenger side under hood fuse panel - my air cond. doesn't work anymore, so I pulled that fuse. Not sure if related, but the power to the cooling fans was lost. I replaced with an aftermarket controller. Afterwards, I replaced the car's brain also and had perfect operation for the last few years, but the problem has returned in spades. To my untrained eye it seems possessed...

Thank God all this information will fix today should have taken back to dealer but they are crooks don't even have 40 k on it