WHAT WENT WRONG?
You don't need to know the words to find the answer. Find what happened to your car below and it'll point you at the part that explains it. Everything here is free and nothing asks you to sign up.
RACING AN ESC? START WITH THE RIPPLE PACK.
The caps at the ESC are the part most likely to let the smoke out, and the first thing to get right. Size yours in the Ripple Pack calculator, then build it with the Ripple Pack Build Guide.
BRAND NEW AND NOTHING HAS BROKEN YET?
Start with the Gearing Guide — it's the most picture-heavy one and it explains how the whole drivetrain multiplies together. Then the Glossary whenever a word stops you.
MY ESC LET THE SMOKE OUT
Usually the capacitors on the ESC's power bus, not the ESC itself. At part throttle those capacitors carry more current than your battery does — at 30% throttle a logged 180 battery amps means 600 amps in the motor and 275 amps in the caps. Most people size a cap pack by microfarads. Milliohms are what matter.
MY MOTOR IS TOO HOT TO TOUCH AFTER ONE PASS
A motor's continuous rating assumes it runs forever. A drag pass is two seconds, so the real limit isn't amps — it's how much heat energy the copper can soak before the enamel gives up. There's an actual number for it, in joules, and you can work out whether you're over it.
MY MOTOR LOST ITS PUNCH AND NOW REVS HIGHER
That's almost certainly demagnetization. You permanently weakened the rotor magnets, probably with a big current spike while the motor was already hot. A kV that comes back higher than the label is magnet you no longer have, and it does not come back.
MY CAR WON'T HOOK UP — IT JUST SPINS
Two different problems wear this disguise. Either the gearing is putting more torque at the tire than the surface can hold, or the pack is sagging so hard that what the motor actually receives has nothing to do with what you planned.
MY PACK SAYS 100C BUT THE CAR STILL FALLS OVER
C ratings are marketing. The number that decides whether a pack holds voltage under a launch is its internal resistance, in milliohms, and most sellers don't publish it. Two packs with the same label can behave completely differently.
I DON'T KNOW WHAT GEARING TO RUN
Pinion, spur, diff pinion and ring all multiply together into one final drive number, and that number plus your tire diameter and kV decides your top speed. It's arithmetic, and the calculator does it.
I DON'T KNOW WHAT SIZE BATTERY TO BUY
Work backwards from the run instead of guessing: how heavy the car is, how fast you want to be at the end of 132 feet, and how much voltage the pack will give up getting you there.
EVERYONE SAYS ADD CAPACITORS — HOW MANY?
More microfarads is not automatically better. Ripple volts are set mostly by the caps' ESR, so a handful of low-ESR caps right at the ESC beats a big pile. The 550 A launch spike lasts milliseconds, so 5 to 9 caps, not dozens, keep ripple under 10%.
THE PACK SAGS UNDER LOAD
Voltage drop under load is a battery job: more cells in parallel (or a second pack) hold the voltage up for the whole pass. Ripple caps at the ESC are a different job: keep those.
THE CALCULATOR ASKED ME SOMETHING I DIDN'T UNDERSTAND
Every field has a ? next to it that says what it means, where to find it, and what to do if you don't know. Every calculator opens with realistic starting numbers so you get a working answer first and learn by changing one thing at a time.
Still stuck, or something here doesn't match what you're seeing? Tell us and we'll add it to this page: evul@evulempire.com · (724) 338-8557. There are no stupid questions here — if a page confused you, the page is wrong, not you.