question

Are you talking about the VE.BUS smart dongle, or the Smart Sense? If you are talking about the smart sense, I see no reason to have that when you already have a smart solar and smart bmv (712). They can create their own bluetooth network between the two and you can get the temp from the temp sensor on BMV. As for the multi, I don't think you can share that data without a venus device (CCGX, Venus GX, Pi, ect.). However the 12/3000 shipped with its own temp sensor and has a dedicated voltage sense. KEEP IN MIND THAT THE TEMP SENSORS FOR THE BMV AND MULTI ARE DIFFERENT. If you want to get a temp sensor on the bmv, you have to get a specific model: ASS000100000.

If you mean the ve.bus smart dongle, currently it's cant share it's info with the VE.Smart network so it's only for the multiplus. It does have the advantage of being used with Victron Connect App, but right now it can't share it's information to anything else. However based on the wording of the manual "At this time, the VE.Bus Smart dongle cannot send its temperature and voltage data as part of a VE.Smart network." that might change. If you want an external temp sensor (instead of the built in one on the unit, it's the same as the BMV sensor: ASS000100000