Provide a single series chain that de-energises the tractive system if any safety device opens.
Every shutdown device is wired in series: shutdown buttons, inertia switch, brake plausibility device, insulation monitoring device and the BMS fault output. Opening the chain anywhere drops the accumulator isolation relays. Design Philosophies and Processes: Inherited from the Accumulator LV subsystem design process: 1. List every low voltage function inside the container and what it must interface with. 2. Decide grounding architecture (star chosen) and lay out the returns. 3. Design the boards, with conformal coating selected against the requirement (acrylic is easier to rework, silicone is more vibration resistant and more temperature tolerant but costs more and is harder to remove). 4. Design HV monitoring: optocoupler (smaller, cheaper, digital, needs conformal coating) against voltage transducer (no conformal coating needed, larger, more expensive, analog). 5. Build the sub-harnesses, test in simulated conditions before the pack is live.
Contactors do not provide reliable state feedback. Without it the tractive system could remain energised while the shutdown circuit believes it is off. Mechanical wear or bounce can give inconsistent readings on budget contactors. Adding contactor AUX feedback is the identified fix and is needed to pass the tractive system master switch safety checks.
Nothing in CrimsonStorage covers these yet.