I have a 5v pro mini running off a 12v regulator. The 12v Reg is connected to two 9v batteries in serial creating total of 18v input. The output of the 12v Reg is connected to the raw input on the pro mini. It’s a brand new pro mini and I have used them before but not with 12v input. The pro mini VCC is reading 12v which isn’t right. Does this mean the regulator is bad?
How 'bout you post a bit of a schematic or even a picture of your set up.
For all anybody knows, all of you wires are melted together in one big blob.
If the Vcc pin on Pro-mini reads 12V (instead of 5V) you have blown the onboard regulator and the AtMega chip; in other words the Pro-mini regulator is history.
If you want to use the “RAW” input for 12V and 18V you can do this but connect diodes to separate the supplies, i.e. with cathodes of both supplies to “RAW” - that way EITHER the 12V OR the 18V will happily supply without influencing the other. If you don’t do this you would be trying to charge the 12V supply with the 18V supply = not good!