Emmvee Solar Vehicle Test Engineer Interview: Rounds, Questions and Preparation

What the job involves

A Vehicle Test Engineer in the EV and cleantech sector plans and runs tests on electric vehicles, batteries, motors, and controllers to check performance, safety, and reliability. On a typical day, you may set up sensors, run dyno or road tests, log data, and write reports that help design and quality teams fix issues. At fast-growing companies, you often support prototype builds, validation schedules, and compliance checks for Indian and export markets.

Role and EV Fundamentals

1. 1

   What are the main components of an electric vehicle powertrain, and what does a test engineer check on each?

   Cover battery pack, BMS, motor, motor controller, charger, and reduction gear. For each, mention one key test such as capacity test, insulation resistance, efficiency map, or thermal run.

2. 2

   Why is battery testing important in an EV, and what parameters do you record during a battery test?

   Explain safety, range, and life. List voltage, current, temperature, state of charge, internal resistance, and capacity. Mention charge and discharge cycles and abuse tests.

3. 3

   What is the difference between a dyno test and an on-road test for an electric vehicle?

   Dyno gives controlled, repeatable conditions for power, torque, and efficiency. On-road tests capture real vibrations, thermal loads, and driving cycles. A strong answer says both are used together.

4. 4

   What safety precautions do you follow when testing a high-voltage EV system?

   Mention PPE, insulated tools, lockout-tagout, de-energizing and verifying zero voltage, using rated meters, and never working alone. Show awareness of Indian EV safety guidelines.

Technical Tools and Methods

1. 5

   How would you use CAN bus data during a vehicle test, and what tools have you used?

   Explain that CAN carries messages from BMS, controller, and sensors. Mention tools like CANalyzer, PCAN, or Arduino with MCP2515. Say you log signals like motor RPM, torque, and battery current.

2. 6

   What sensors and instruments would you use to measure motor temperature, current, and vibration?

   Name thermocouples or RTDs, Hall-effect or shunt-based current sensors, and accelerometers. Mention calibration and placement to avoid noise and false readings.

3. 7

   How do you ensure your test data is reliable and repeatable?

   Talk about calibration, controlled ambient conditions, same test profile, multiple runs, and checking outliers. Mention documenting setup and using statistical checks like standard deviation.

4. 8

   Which software do you use to analyse test data, and how would you plot a motor efficiency map?

   Mention MATLAB, Python with pandas and matplotlib, or Excel. Explain that efficiency map plots torque versus speed with efficiency contours from measured input and output power.

Practical Scenarios

1. 9

   During a road test, the BMS suddenly shows a cell voltage drop. What steps do you take?

   Stop the test safely, isolate the pack, check the cell and connections, review logs for temperature and current spikes, and report to the design team. Show a methodical and safety-first approach.

2. 10

   Your test shows the motor drawing more current than expected at a given load. How do you investigate?

   Check calibration of sensors, mechanical binding, controller settings, and phase resistance. Compare with baseline data and repeat the test. Mention documenting findings clearly.

3. 11

   You need to validate a new battery pack for a small electric commercial vehicle in summer conditions. How do you plan the test?

   Define objectives, choose test cycles, set up thermal chambers or real-world runs, monitor temperature and SOC, and include safety limits. Mention Indian summer ambient conditions and duty cycles.

4. 12

   A prototype fails a vibration test. What could be the reasons, and how would you support the fix?

   Consider mounting points, connector fatigue, PCB cracks, and cable routing. Suggest adding strain gauges, repeating with modified design, and documenting before and after results.

Behavioural and HR Questions

1. 13

   Tell us about a time you worked in a team to complete a project under a tight deadline.

   Use the STAR method. Highlight your specific role, how you coordinated, and the result. For a fresher, a college project or internship works well.

2. 14

   Why do you want to work in the EV and cleantech sector, and why our company?

   Show genuine interest in clean mobility and India's EV growth. Mention the company's products or market and how your skills fit. Avoid generic answers.

3. 15

   Describe a time you made a mistake during a test or project. What did you learn?

   Be honest, choose a small and safe example, and focus on the lesson and the corrective step you took. Show you value safety and accuracy.

4. 16

   How do you handle working in a fast-growing company where priorities change quickly?

   Talk about staying organised, communicating early, and being flexible. Give an example from college or an internship where you adapted to a change.