This is the index for Field Notes — everything that broke on a student-built Formula Student EV car, in the order it broke, written by the person whose name was on the electrical system when it did.
Three motor controllers died in one season. We bought a train ticket for one of their replacements. We spent two hours at a competition trying to discharge a capacitor into a concrete floor. Every post below is one failure, what it cost, and how we finally measured our way out of it. Each one stands alone — start anywhere.
Start Here
Student EV Race Car: 3 Dead Controllers and What a Brutal Season Taught Me
The overview. Two years, three controllers, one broken suspension arm, and the error notebook that turned into this blog.
The Season, Failure by Failure
1. Reverse Polarity Damage: How 12 Volts Killed Our Motor Controller in Ten Seconds
8 p.m., the night before test week. I swapped supply and ground on a pedal connector. One click, then silence — and a controller rated for hundreds of amps was dead. Four rules for anyone building a Formula Student car.
2. What Actually Happens When You Press the Gas Pedal in a Modern Car
Our car insisted a foot was on the throttle when the seat was empty. The pedal was innocent — one parameter was 0.05 V out. How to wire a pedal to a controller without losing a test day.
3. How to Find a Car Wiring Problem With a Multimeter
Our harness was held together by WAGO connectors and optimism. One of them looked perfect and was lying. Four habits that will save a student team’s season.
4. EV Slow Acceleration: We Blamed the Gear Ratio. It Was One Number.
Full throttle, and the meter read 30 amps. We spent weeks arguing about sprockets. The fix took ten minutes and cost nothing. If your car feels slow, do this in order.
5. Motor Controller Residual Voltage: How We Scored Zero on Day One of the Competition
The car ran everything we asked of it, nothing broke, and the results table still said zero. Twenty volts were still sitting in the controller ten minutes after shutdown. What to do if your competition makes you run an energy meter.
What This Series Is For
A student team loses its memory every year. People graduate, the handover report gets thinner, and the next lineup fries the same part in the same way for the same reason. These posts are the notes I wish someone had left us — the numbers, the datasheet lines nobody read, the two hours of dignity we lost in a paddock.
The season isn’t finished here. Somewhere in the middle of the endurance race on day two, the water cooling stopped working, and the controller — our third that season — started climbing toward the temperature where controllers stop being controllers. Everyone told me not to open the pump.