Singh states using 30 to 35 V with 15 to 18 A. Sundaresan worked at 10V with 20 to 25 A initially and later lowered to 15A.
Albeit Santilli has not done a specific replication, he has reported changes in the carbon rods, but he works with a 24KWh welder.
As the intensity of the magnetic field of the plasma is allegedly what drives the process, perhaps using higher amperages is a requirement.