Well, the converter wires run directly to the 12 volt panel. The batteries are charged from the converter.
The Iota guy stated the fuse will blow if the power to the 12 volt panel is wired incorrectly.
http://www.iotaengineering.com/pplib/27vdlsmanl.pdf
http://www.iotaengineering.com/pplib/idp30.pdf