159 2.4 voltage spike

[Bobm]

Hi All,
Just replaced the Alternator in my 2007 159 2.4 Jtdm with a new one, same make, Denso.
Test drive OK. 2 days later I get numerous warnings..ABS, EBD etc and display between instruments blank.
Faults reset. Battery replacement suggested after load test. New battery fitted.
Test drive brings up same faults only this time engine momentarily cuts out.
Multiecuscan shows P0560 Battery Voltage....signal high, parameters confirm with a voltage spike to 18 volts at around 3000 rpm.
Is it possible to have a dud regulator on a new alternator, or is it some other system component.
Any ideas appreciated.
Bob.