[Al Skierkiewicz]

Dave,
It sounds like you have done everything I could have suggested. I am glad you are using #10 for the Chalupas as many teams try to get away with much smaller wire. We also solder our crimp connectors by using uninsulated crimps and heatshrink.
It is my understanding that the Radio modem and RC have a switched power input and watchdog circuit. When the primary voltage falls below 8 volts for some length of time, the two devices and all PWM power switches over to the backup battery. This keeps the RC from rebooting and keeps the modems in communication. (about a four second process after power on.) Unfortunately, four motors in stall coupled with the resistance of the main battery and the series resistance (as small as it is) will combine to drop voltage when current is being drawn. With four small Chalupas at stall, you could have as much as 400 amps of current flowing for short periods of time. That translates to as much as 1 volt drop when the battery is fully charged. If you have a scope compare voltage at the battery terminals and then move the probe and ground lead to the input of the RC or Victor. Run your motors and then reverse them and see the dip in the input voltage. I think you will be surprised at the difference. As to adding caps to the output of the Victor, this move is not legal, but was suggested as a fix last year. The Victor has some suppression built into the motor outputs. (Teams were reguired to add Varistors to the inputs on the old 883 controllers) Several years ago we had designed a custom circuit we called StangSense. It was a multichannel current monitor that would record the current in several loads and port it out the dashboard along with battery voltage and timer tics. This allowed us to analyze robot current and voltage while having a rough idea of what events in a match caused the data to change. We were not ready for what we saw. We made a portable version which we used to analyze other robots and the data was so accurate we could predict robot controller failures for teams. At that time it was a real issue since the RC was pre backup battery design. We regularly found dips in RC voltage below 4 volts on some robots including our own. That prompted a major change in wiring layout and wire size design as well as connector choice and soldering.
All things being equal, I think you have minimized the interaction. We are dealing with an unknown radio at this point and I don't think we fully understand what these new radios are capable of. I am sure we will have more data in the next week or so.