Tesla Software Engineer Interview Experience — Supercharger System Design Where I Never Got Past the First Requirement

I was asked to design a supercharger with 3 requirements:

• FR1: Billing / amount of energy delivered (stored in the backend)
• FR2: Health metrics/telemetry from the supercharger stall (long-term data store)
• FR3: Screen/in-car application: touch the map, nearest available supercharger (price)

I tried to follow the script and design an HLD per FR as quickly as possible, but the interviewer wanted to understand each part of the design. For example, when designing FR1, we chatted about routing, secure communication, DNS, local buffers, sync vs. async, etc.

I don't think I am going to pass because I couldn't even get to FR2. This part of the interview experience is quite frustrating, to say the least. Every interviewer seems to have their own preferences when discussing designs, and it's impossible to peek into their head to understand what they want. Disappointed, but onto the next one.