I was in heavy traffic when i noticed a burning smell was my fuse box under the bonnet passenger side. The wiring plug had melted, when this happened my ignition lights where still on but wouldn't turn over. i managed to tape up the melted wires to get me home, but my battery light was on. took the car to a garage n they said the alternator over charged and melted the wiring.
so the tested the fixed wiring and it came back clear so it was down to an alternator not charging the battery that's why i had the battery light on so went and got 2 new alternators and still battery light on, however when i get the car running when i rev it hard the battery light goes off and then back on again just got it bump started there it ticks over but when i try to rev it cuts out now battery light is off when ticking over.

any thoughts on what the problem could be?