There are many types, and I believe this one will work. From what I read most members are using it on the negative cable (which is not always the black one on these campers).
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Steve & Sue
2017 Grand Design 297RSTS Travel Trailer
2017 Ford F-350 Lariat Crew Cab diesel 6.7 SW LB 11,500 lb GVWR package
Former: Crossroads ST26RB
I went with one like this. Mounted to the bottom of the propane support beam exterior to the the battery boxes but on the frame outside. Been on for a year, no issues. I liked that the connections are all protected from the weather.