I have a BMV-702 and I'd like to be able to use the VictronConnect mobile app without the expense of the $50 Victron Bluetooth dongle. Instead I'd like to get there with a $2-10 (depending on where you get it) generic BLE module.
I've tinkered with the VictronConnect app on MacOS connecting to the BMV-702 via a generic FTDI USB-TTL cable - and that works fine. So I suspect there is no particular proprietary magic on the BMV-702 TTL connector. I've also used a generic serial/terminal app to monitor
the plain text output the BMV-702 sends on this port.
I think the real mystery is in how the VictronConnect mobile app discovers Victron devices via bluetooth. I've searched high and low and not found much detail on that. I suspect they are using BLE GATT attributes to recognize devices. I'd like to test that hypothesis.
If you have a BMV 700/702/712 with bluetooth, can you please use a diagnostic mobile app such as "LightBlue Explorer" (free) to capture some details of how your Victron BMV device advertises itself on bluetooth. Use LightBlue to connect to your device - which probably shows up as "VE.Direct LE". Tap on it to connect and post screenshots of the "Peripheral" screens which should list "service" and "device information" with "manufacturer name string" and "model number string" attributes among other things.