ABS noise

[Sachannie]

I have a loud clicking/ tack, tack noise coming from ABS box on my Mercedes 190.

First heard yesterday after arriving home from local shopping trip.. (no speeding or desperate braking been done) !!! Turned off engine and this noise starts.
No noises heard while driving.

Noise continued as far as I know for an hour or so, but intermittently. on for 1 minute or 2, then off for some minutes. Doing this for at least an hour, possible longer.

This morning, battery dead. Put on charge, clacking noise straight away, then stops. Doesn't start again. Start up car to see that charge has worked, ok, turn off, clacking sound for minute then stops, and no more. But I've put back on charge.

Have been having problem with battery not charging up while driving. alternator and belt has been replaced, all checks done, connections and so forth, battery is fine.

PLEASE can someone tell me what this noise might be, (and if it may have any connection with the battery problems, or just ran it down over night)

Don't really want to blow up the car