Wrong Alternator Fitted (ASR Light On)

Octavia 2002 1.9Tdi ASV.

Red battery light came on last week,driving home, the wipers got slower and  slower.fault lights started popping up on the dashboad(air bag,ASR etc)

I got home and tested the battery with a voltmeter across the terminals with the engine running and 12.5 volts and dropping.Switched off and car wouldnt start so I used my pocket jump starter from Costco and started no problem.I messed about over two days ordering and changing the rectifier/brush pack(£17 off ebay)I did this on the car as there is just room.Anyway didnt work so purchased a new alternator from Eurocarparts for£85(special 75% off)This was not two difficult to change(3 hours)it work ok at charging battery and I drove it for several days with no problems.The only thing was the ASR light came on the dash 10 mins after I started,every time.Stuck my VCDS and it showed 17911 Loadsignal implausable from alternator.After loads of Googling I could see about the broken wiring causing this problem so checked wiring and no breaks,after several days of torment I decided I had fitted the wrong alternator,the original was 90 amp and I had fitted a 120 amp,Ii thought the signal from the connector on the alternator DFM must be sending out of range signals to the ecu hence the ASR light coming on.Fitted 90 amp alternator and bye bye ASR light.Hope this may help someone.