The first time our student EV race car killed a motor controller, it took ten seconds and one wire. Twelve volts. I’m a third-year electrical engineering student at Chung-Ang University in Seoul, and I run the electrical systems on our team’s car — wiring harnesses, battery packs, CAN communication, and all the sensors nobody thanks you for until they fail. The team is called Create Our Car (COC), and we build a car every year for Formula Student Korea (FSKorea) — the Korean round of the same Formula Student series that runs in Germany, the UK and the US. We compete in the EV class, so everything on the car that moves is downstream of something I wired. This blog is where I write down what the car teaches me, which is almost always the hard way.
Our team is only three years old, and a student EV race car is a machine that punishes you for every assumption you don’t test. We’re not famous. Half of what we know, we learned by breaking something at 2 a.m. first. But we’re getting quick, and this season we’re seriously aiming for a podium.
What a Season on a Student EV Race Car Actually Looks Like
Mostly it looks like failure, documented. Here is one season, compressed.
We killed three motor controllers. The first one died at 8 p.m. the night before test week, because a thin signal wire went into the wrong pin — power and ground, reversed. The controller is rated for 48 volts and sits behind a 400-amp fuse. The wire that killed it was carrying twelve. We finished the season on our third one, a liquid-cooled Golden Motor VEC500.
We replaced it by buying a KTX ticket — a seat, an actual seat meant for a human — and putting the replacement controller in it. Another university team put the box on the train, we collected it at Yongsan Station, and it was on the workbench by 11:30 that night. It cost an amount of money I still don’t enjoy thinking about.
We spent weeks wondering why the car felt slow, then put a meter on it and found the car pulling 30 amps when it should have been pulling closer to 200. One parameter — the controller’s battery current limit — had been left at 60. We raised it, the car turned violent, and I grinned for a week.
We lost a full test day to an aftermarket pedal that measured perfectly on the bench and collapsed to a fifth of its range the moment it was wired to the controller. We blamed our wiring for hours before accepting the pedal simply wasn’t compatible.
We scored zero in the slalom because of twenty leftover volts sitting in the controller, and fixed it with a resistor taped to a wire. Our water cooling pump quit at the competition; there was a rock inside it. And seven laps into the semifinal, closing on first place, the car quietly switched itself off.
Every one of those has a diagnosis behind it, and I’m writing them up one at a time. Nothing about a student EV race car fails the way you expect it to — that’s the whole reason the stories are worth telling. This page is where the list will live.
Why I’m Betting on This
Here’s my dream, written down so I can’t quietly delete it later: I want to make enough money to spend weekends at a circuit doing time attack in cars I love, without checking my bank account first. And on graduation day, I want to arrive in a BMW M2. Not a rental. Mine.
Probably not on a salary, then. A while ago I won a top prize at a startup competition, and it settled a question I’d been circling for months: I’m going to build my own thing. What changed the math for me is AI. I recently wrote and shipped working C firmware for our race car’s ESP32 telemetry system in about two weeks, with AI as a very patient pair programmer. Our team had assumed we’d need to recruit a software major for that. We didn’t. Work that used to require hiring now requires directing tools well — and I’d rather learn to direct.
I’m not romantic about it. AI output still has that AI smell sometimes, and my teammates tease me for running everything through it. But I watched the same movie happen with the internet: the people who adapted early looked silly for about five minutes, and then they didn’t. My test is simple — does it save me time or money? If yes, I’m in.
Fundamentals, and an Error Notebook
The other thing I believe in is fundamentals. I learned that the embarrassing way, through football: I was a decent striker in middle school mostly because I was tall, then got thoroughly humbled later by guys who had drilled the basics. Math went the opposite direction — I spent two dull years repeating the same foundations until they set, and every course after that got easy. Same lesson from both sides: fundamentals compound, shortcuts don’t.
It’s why I keep an error notebook. A mistake I’ve written down once doesn’t get to beat me twice. That habit is the reason this blog exists at all — most of what you’ll read here started as a line in that notebook, written at 3 a.m. by someone who had just broken something expensive.
What This Blog Is
I write about cars the way I actually work on them: tools I really use, electrical faults I’ve really diagnosed, and how the technology in your car actually works — from someone who spends his nights elbow-deep in a student EV race car’s wiring harness. Everything here comes with the numbers we measured and the wrong guesses we made first.
If I get something wrong, tell me. Corrections get priority here; being right matters more to me than looking right.
Start with the multimeter, because that’s the tool that solved almost every story above. Then read about what your gas pedal is really doing — it’s a sensor, and ours once decided a foot was on it when the car was empty.
Read next → How to Find a Car Wiring Problem With a Multimeter
The tool that solved almost every failure above — including the connector that looked perfect and wasn’t.
Series: This is part of Field Notes — everything that broke on our Formula Student EV car, in the order it broke.