I have a s-13 with a s14 ka swapped by some idiot and when i drive it the battery dies ..... i tested the alternator it seems to be good .... checked the battery its good so what could it be it seems to die really fast when i turn on the headlights the car will bogg when i the battery starts dies and the radio shuts off broblem seems to be getting worse please let me know if u have any ideas

 

its probably the little wire that goes to the back of the alternator. that's the wire that gives the alternator its "starting charge" the s13 one is different from the s14 one so it probably isn't making a good connection.

that's where I'd start.