Fault Detection Circuit

Objective: Develop a tool to plug into a 24 cell battery stack to detect all incorrect wiring issues. The circuit should meet the following:

  1.  All components must be simple and inexpensive
  2. Limit the number of components as much as possible
  3. Detects all overvoltage and undervoltage conditions ranging from 0 -> -103.2V and 8.6V -> 103.2V

 

Electrical Circuit Design

Overvoltage Condition

8.6V

100V

Undervoltage Condition

-4V

-100V

Normal Condition (4.3V)

Process

  • Defined the fault and normal condition ranges to set clear guidelines the circuit must meet.
  • Iteratively refined the circuit to resolve cascading design dependencies, ensuring each modification addressed new fault conditions without invalidating prior solutions.
  • Selected components with the compliant specs for the circuit.
  • Prototyped and verified the circuit for all conditions. 

Results

  • Developed a working circuit which identified all fault conditions.
  • The circuit uses only simple components which are very cheap such as diodes, zener diodes, LEDs, and resistors.