Sounds like somethign si broken somewherew, posibly at a oin or inside it's insulation, probably as it goes round a bend, wires get stiff and brittle with age. Is it a NEW alternator or a new to you alternator, either way get it checked it might be at fault and if it is new you can get a new one free. Have you got an alram/immobliser? is it workign correctly as that maybe the cause of the iognition stuff not working correctly.