Why not integrate Jaguars with Diodes?

[Kevin Sevcik]

Originally Posted by lemiant

The diode wouldn't have to affect all the power, just the power going to the control circuitry. If the jaguar's internal computer didn't turn on, it would never send any signals to the internal relay (or whatever they use) and nothing bad would happen. The computing uses a lot less amperage so this is totally feasible.

I'm a bit late coming to this, but I feel it necessary to point out that you have to protect the power circuitry as well as the logic in this application, which is why it's so complicated and expensive. The MOSFETs that make up the H-Bridge all contain a body diode as part of their construction. When properly powered, these diodes are reverse biased relative to the battery terminals. If you reverse the polarity on the battery terminals, you now have pretty much a dead short across two diodes and a 1mOhm current sense resistor. An FRC battery is going to dump enough amps into that circuit to melt something pretty quickly. (My money's on the current sense resistor, I've heard about them desoldering.)

Matt,
If you want to drastically reduce the chance of swapped quick connects frying something, keyed connections are the way to go. Anderson power pole or molex connectors will do this for you. Or you can do what we do with quick connects: Swap genders from one polarity to the other. So a positive out of your PDB gets a male QC, and a negative out of the PDB gets a female. As long as you're consistent across the whole robot, it doesn't hurt interchangeability, and you really reduce the chances of that particular failure. Or the chance of wiring a motor up backwards, etc.