Hi - I'm a trade seller / installer. My customers sometimes want to charge their vehicle batteries from their solar, as well as their regular leisure battery/ies. I currently use Epever Duo chargers but they've now dropped support for iOS latest version with their Bluetooth dongles.
A Victron solution would be great - I sell a lot of your smartsolar 75/15s (and some bigger ones) - the app is great and my clients don't have bluetooth issues.
To offer van battery charging too, could I hang one of your small DC DC chargers off the load terminals on the 75/15? then connect this DC-DC output to the starter live? I want to use the load outputs as I want the 75/15 to manage to port, auto disabling it if it wants to prioritise the leisure battery, as it currently does with the "battery life" profile.
The main questions are: can I do it? and, which model DC DC charger? - It only needs to be a few amps maximum (Bluetooth would be nice so it also shows up in Victron Connect app), and I don't want any kind of engine running detection / or be able to disable it - it needs to work all the time it is given source power.