@Cruiserdrew and I have sat in camp on the Rubicon trail and monitored the Victron charge controllers on 4 other nearby rigs all while sitting in the shade under an awning drinking. I think they all had the external BT dongle. As @george_tlc says, the dongle is a short range radio module, so keep it away from the metal body of the truck and elevated and you’ll marvel at how far the connection to your phone can reach. OK, I’m chilln’ now while my batteries top off...
Well, if you can get the other guys' data while drinking some



(Note to self: go change my PIN from default...)