P38 battery drain. Alternator fault?

Hi. I'm new to the forum so sorry if this is the wrong place to ask this question. I have a battery drain problem and after trying everything including an rf receiver replacement I've noticed that when I disconnect the alternator at the live terminal of the alternator, the battery drain stops. The alternator is less than a year old but could this be the problem I.e should the alternator draw current (about 2.5 amps) when everything is switched off.?

:welcome2:

Yes.

No.

Thanks Diddypud. I appreciate that it may have seemed a stupid question but thought it worth asking before I spent more cash on the wrong solution!