Can I split the wires going to the plotter so they also go the nmea bridge's input wires?
You can connect your AIS/GPS output to the NMEA Connect 4.0 input, and the NMEA connect 4.0 Output to the plotter.
No, you can't get the magnetic and hell trim data from the ultrasonic on your NMEA network with the NMEA connect.
And also, can we connect via serial and send the data using our own methods?
Ultrasonic Wired Wifi, sends by both by cable and Wi-Fi (AP or Infrastructure) the data generated
by the wind equipment (wind, gyro, compass). The equipment does not forward the data from the
NMEA CONNECT bus via Wi-Fi; it only outputs the NMEA wind equipment data not the NMEA
CONNECT input.
Most likely, you are seeing some spikes from the Bluetooth signal. This is a normal behaviour, but on average the power consumption is about 35mA.