1 to 2 Volts of _Voltage_
The units of power are Watts: Power = Voltage × Current
Power is also Velocity × Force, which means there is already a Register unit of power:
1 sheep·jub = 123.5MW
The real challenge is to find the unit of power used by the wind turbine industry. 1 Windmill (when the wind is just right) is equivalent to so many million homes (with gas heating, hot water and cooking + free public transport). If anyone can find this home, we will be able to calculate the number of sheep jubs per windmill.
Register units lack a direct unit of time, but one can be inferred from distance and velocity:
1 second = 41970000 linguine per sheep
Register units do not include a unit of charge or anything that involves charge, so there are no Register units of voltage or current.