Ok. Sorry for that. The MPPT and BMV are constantly sending data, if I use the first code then the rx/tx leds flash breifly once I plug the arduino into the usb port, after that the tx led flashes every couple of seconds as it gets the data from the device plugged in at that time and passes it on (to what I do not know as I have then not opened the Victron connect app).... Once I open the app it starts looking for devices when it does that the arduinos rx/tx leds flash (I suppose a handshake of some sort) where after the tx led on the arduino flashes every few seconds, by then in the software whatever I have plugged in on that UART then appears in the window, I can then click on it and the readings are then displayed in GUI format, the code sent is ASCII format if you would like I can attach the code and a screen shot of the GUI?
The MPPT is a Blue solar 150/35
and the BMV is the BMV700.
Thank you.
Kind Regards.
Charles from Namibia....