external BEC hookup....being stupid

[pscm]

I am setting up a new machine with an existing robird setup but need to hook up an external BEC. I am running to spektrum sats and don't fully grasp how to hook up. I get that I have to remove the red wire from existing internal BEC plug but not sure how to wire into the robird. Are there any schematics/drawings available?

[blade_crasher]

You have two options. Since the Rudder power is on separate bus, you need to provide power to that point in addition to the main bus via the Throttle port on the G31.

You can wire the ground leads from your BEC to the black lead from the ESC and then remove the red wire from ESC and tape that back safely, replacing it with the red lead from the BEC. Plug this into the throttle port, and your now feeding BEC power to the Robird but the signal is coming from the ESC.

You still need to use a female - female wire from the SRx1 to the SRx2 to take feed power to the rudder.

Option 2: Provide the G31 with twin power sources. This is what I did. The ESC red wire is retained, and provides power to the cyclic side and the G31 in general. I then used a 3amp BEC to provide 5v to the Rudder side. This gives you the ability to run different voltages on the cyclic and tail easily.

There is a third option which I have never explored but you can open the case and solder across the bus inside the box, and you then don't need to provide power to the rudder side at all. In fact you could probably use the SRx2 port for SAT and an input for a BEC and just leave the ESC red wire removed from the throttle port.

Hope this helps. Others, far more knowledgeable than me may have other thoughts.

[Jazzjohn]

One way is to keep everything as is ( with the red wire disconnected as you mentioned) and run a Y cable at the motor connector on the Robird. The external BEC output would then feed into the Y along with the esc cable.

[pscm]

To clarify, if I run any cord then this is just replacing internal bec power with external as I am removing internal power and the two remaining wires are a shared source?

[Jazzjohn]

Yes, you are substituting one 5 volt source for another.
Of the two remaining wires in the connector, one is a shared ground ( the negative side of main power) and the other is the throttle signal that goes to the esc.

[pscm]

So do I need to also removed the throttle signal wire from the external BEC or is it not even there to begin wit?

[Jazzjohn]

The external bec is only a power supply with plus and minus inputs and plus and minus outputs. Four leads total. There should be no connection from the bec to the Robird's motor connector's signal pin. That pin connects to the esc input only.

[pscm]

I got a castle 10 amp coming. In the pic it appears that the receiver plug has 3 wires but we wil wait and see. Your statement makes complete sense.

[Jazzjohn]

The signal wire on the bec is for programming the output voltage to something other than the default 5.1 volts. You won't need to connect that wire but it can be left connected through the Y connector or you can pull it out.

[pscm]

Thanks