User guide
Descending hills on an electric scooter: brake fade, thermal management of disc brakes, regen overcharge at 100 % SoC, cadence-braking vs continuous drag, runaway-stop drill
Descending is not the mirror of climbing. If climbing stresses the motor and battery, descending stresses the brakes (friction μ vs temperature), the fluid (boiling-point physics — 280 °C / 270 °C / 140 °C), the rotor (mechanical fade, warping after sudden cooling), and the BMS (regen lockout at 100 % SoC). Potential energy of a 90 kg rider plus 25 kg scooter on a 10 % grade at 25 km/h equals P_diss = m·g·v·sinθ ≈ 780 W of continuous thermal power to both discs; in one minute of descent that's ≈47 kJ of heat that has to go somewhere, otherwise the pads cross the kneepoint of the temperature-friction curve and abruptly lose half their braking force. This guide is an engineering-practical protocol: physics of thermal power, three brake-fade mechanisms (friction / fluid / mechanical), DOT 5.1 vs Shimano mineral oil boiling points (270/190 °C vs 280 °C), regen on a full battery (why the BMS shuts it down, mech-only until SoC ≤ 95 %), snub-and-release instead of continuous drag (short cycles of 3–5 s with a cooling phase), pre-descent SoC strategy, 5-step runaway-stop drill. Sources ENG-first: Wikipedia Brake fade, MDPI bicycle disc brake thermal performance (Sensors 2018, 2021), PMC 10779514 — friction coefficient modeling, BikeRadar / Singletracks — fluid boiling points, ShipEx — snub braking, Endless Sphere — downhill regen power, Stromer / Electric Bike Forums — regen disabled on full battery.