on this bac-alarm, is there a metal tab attached to the negative connection screw/stud that also is bent around to allow the mounting hardware to go through a whole in the tab? on electric forklifts this tab must be removed.
are you saying that even with the alarm wired direct to the battery positive and battery negative heavy power cables, it does not beep continuously and is effected by the operation of the truck??
there may be some instructions around somewhere that show how to install a small diode and capacitor to act as a noise filter on the alarm's circuit to cut down the electrical noise that interferes with the alarms operation