New alternator but battery light still on??

[silverback mike]

evening all....
As above really, the dog carrier (e39 523i) has had a new alternator but the battery light is on, I haven't driven it for a few days and was dead this evening. Could this be a faulty battery? It's on it's original (R reg) I haven't come across this before
Thanks in advance

[silverback mike]

Bumpety bump :-))

[SS2.]

Could well be a duff battery - a combination of age and goosed alternator might have seen it off.

Have you tried charging it and checking whether it holds a charge ?

[Petrolhead_Rich]

duff battery or bad connection to the alternator, if parked up charged and dying whilst parked up then its most likely the battery though...

[silverback mike]

Thanks chaps!

[TooMany2cvs]

There's probably two connections on the alternator - the big fat permalive to the battery, and an ignition switched +12v. If that wire's fractured or there's some other reason it's not playing (fuse? dodgy ign switch?) then the alternator won't "switch on", so no charge.

Or it could be a duff new alternator...