Alternator was replaced still wont keep charge

[NewBMWguy]

1984 bmw 318i Has had the alternator replaced and car still will not keep charge. What could be wrong did I get a faulty refurbashed alternator?

[SpecM]

possibly, but the battery could still be bad, or you could have some parasitic drain

[hye d]

Hook up a voltmeter to battery , should get about 13.5 volts with engine running at 2000 rpm..

[netcsk]

Did you check that the alternator is grounded correctly? Check for continuity between the alternator body and the chassis of the car.

[Spinning Tires]

A burnt out battery light bulb in your gauge cluster or a broken wire going to the battery light. It sounds stupid but its true

[everlast]

possibly, but the battery could still be bad, or you could have some parasitic drain

^^ bingo.

If the battery is known good (you could always pull it out and take it into a store, most load test batteries for free) then you need to do a test for parasitic drain.

[xwill112x]

clean your battery, if theres enough crud on top of it, it will drain it.