My battery will not hold charge. I bought a brand new alternator (made sure they tested it before I put it in), and had the battery charged/tested. Both were good...
Once I put the charged battery back in my car it starts right up. Next morning the battery is dead.

I checked all grounds and made sure ground was tight on alternator.
Could it still be the alternator? Or is there a drain on the system somewhere?
Need help!

 

you sure you dont have anything draining your batter like an alarm put in wrong gauges put in wrong somthing of that nature becuase if they both tested good then you know its not that so check everything make sure its not pulling power whent he cars off

 

There has to be another drain somewhere, unless your battery just isnt holding the charges because it needs replacing (ALL autozone batteries Ive had did this).
Have you checked dumb things like interior lights?
Do you have an alarm?

 

no alarm... only thing I could think of is my cobra police detector...
It's wired into the pwr plug-in

 

well that is a constant draw on the battery

 

it shouldnt effect the battery if its not shorting or something tho...
the pwr plug-in only gets pwr when the key is in acc 2 i believe...

 

Its time to look for parasitic draw. You will need to hook up a amp meter between the pos terminal on the batt and the pos battery cable ( the amp meter completes the circuit. If you see anything over .25 of an amp then you have something draining power from the battery. About the only thing that will draw any power from the battery with the car off is if you have a clock and or a radio in the car

 

better if you go neg post to neg cable

 

i think i found the problem...
alternator ground nut just spins... wont tighten (probably not enough to get a good ground for the alternator to work) and wont come loosen either!

 

who needs an altenator ground i mean honestly lol i had a very back short circuit completly melted my ground to the altenator it ran just fine cept i couldnt get on it or go past 5k rpms lol but ya get that **** tight and you shouldnt have a problem with it

 

dude, i bought an alternator from autozone and my battery still wouldnt hold a charge so i took it back and they tested it and they said it passed but then i took it to discount and it FAILED. took it back to autozone and then it failed. It at my battery and they gave me one.