If you meant 20-40 volts AC, it's right in the ballpark. Does the stator pass all the ohm tests? Same results when it's hot?
Should do all the ohm tests on the r/r, sounds like it may be shorting out some way. If the r/r passes the tests, running the 12v positive straight (with a fuse) from the r/r to the battery will get it away from Junction Box gremlins. A MOSFET setup will also do that.