Confused: Need power distribution help

ArduRover Miscellaneous
1

I’m starting the process of converting my Traxxas Slash VXL (2wd) to a rover and am pretty confused about the power wiring.

Specs:
APM 2.5
Traxxas Slash VXL 2wd w/ Velineon ESC
CC BEC (5V)
Traxxas Servo

I’m using this writeup as the basis for my conversion:
http://www.instructables.com/id/Autonomous-Traxxas-Rover-Build/?ALLSTEPS

It contains the following description of the power wiring:
[i]IMPORTANT!
The ESC connector will need to be modified by removing the red wire from the connector. This can be done by lifting the plastic tab and pulling the red wire out. This must done because the Traxxas ESC BEC puts out 6V and that will ruin the APM. Once the cable has been pulled out of the connector, it can be taped back with electrical tape, which is the preferred method, or be cut if it will not need to be used in the future.
The board will be powered by the external BEC and can be plugged into any of APM outputs except for channel 1 or 3. Make certain your external BEC is set to output 5V and is not set for 6V.
At this point, you should also make sure the J1 jumper is in place on the APM so the external BEC will power the board and the truck electronics. If you use two separate power supplies (more advanced) or you use the 3DR Power Module along with a different ESC, then you will not use the J1 jumper and will need to remove it.

The ESC (with red cable removed) connects to Channel 3 of the APM output. A servo extension connects to Channel 1 of the APM output and the other end of the cable should go to the servo. If your cable reaches due to your placement, then you will not need the extension. These connections are shown in the third image.[/i]

I also looked at the APM Rover setup guide (http://rover.ardupilot.com/wiki/common-apm25-and-26-overview/), but I can’t figure out which setup category my install falls into.

I can’t visualize the wiring schematic for my setup. I think my install falls into the “No Power Module but using Servos and a high power External BEC” category. Is that correct?

Where the BEC is installed?
Where is the ESC’s red removed?
What is powering the motor and servo?
Is the ESC connected to the APM? How/where?
I need to use the JP1 jumper on the APM, correct?

Any help is greatly appreciated.

2

@mychalm,
If you want great navigation accuracy, forget the APM and get a Pixhawk so you can run EKF.
As far as powering the APM, you cannot use the Traxxas ESC BEC because it does output 6VDC.
I recommend that you power the APM with a Power Module and leave jumper J1 off http://rover.ardupilot.com/wiki/common-apm25-and-26-overview/#Power_Supply_Rails_Not_Connected_Requirements_JP1_Not_Installed.
Removing J1 disconnects the APM 5VDC bus from the Servo Output 5VDC power rail.
Do not remove the red wire from the ESC servo connector as you will need it to power the steering servo connected to the APM Servo Output.
Regards,
TCIII Autonomous Vehicle Developer

3

[quote=“TCIII”]@mychalm,
If you want great navigation accuracy, forget the APM and get a Pixhawk so you can run EKF.
As far as powering the APM, you cannot use the Traxxas ESC BEC because it does output 6VDC.
I recommend that you power the APM with a Power Module and leave jumper J1 off http://rover.ardupilot.com/wiki/common-apm25-and-26-overview/#Power_Supply_Rails_Not_Connected_Requirements_JP1_Not_Installed.
Removing J1 disconnects the APM 5VDC bus from the Servo Output 5VDC power rail.
Do not remove the red wire from the ESC servo connector as you will need it to power the steering servo connected to the APM Servo Output.
Regards,
TCIII Autonomous Vehicle Developer[/quote]

I suspected that the power module might be the answer. This is a “boredom” project that I was trying to do on the cheap with parts I had laying around (hence the APM and the CC BEC rather than a Pixhawk & Power module). If it simplifies things significantly, I can probably spend a few extra bucks to pick up a power module.