I've not done a solar installation, but I would not hook any charging devise to a fused 12 VDC circuit such as the one to the refrigirator. I would wire it either to the battery directly, or to the battery buss at the converter. Just my opinion from years of electronic work.
"The further a society drifts from the truth, the more it will hate those that speak it." George Orwell
In the past: '73 20' Argosy, '74 24' Argosy, '75 23' Avion, '63 24' Airstream, '78 24' Argosy, '75 23' Airstream, '01 25' Airstream, '04 28' Airstream