ISA

Articles, guides, and products tagged "ISA" — a combined view of every catalogue resource on this topic.

User guide

Real-world e-scooter range: an energy-budget model (P_drag + P_roll + P_grade + P_accel), derating from payload / wind / temperature / altitude / tire pressure / speed, and how to convert Wh into kilometres

Why a manufacturer's nameplate range is almost always optimistic by 20–60 %, and how to replace blind trust in a marketing number with your own model: the full power equation (P_drag + P_roll + P_grade + P_accel; formulation from Wilson «Bicycling Science» 4th ed. MIT Press and Martin et al. 1998 Journal of Applied Biomechanics 14(3):276–291), drivetrain efficiency η_motor × η_controller × η_battery ≈ 0.55–0.75 over the full chain, six derating axes from real-world conditions (payload +1 kg → +0.5–1 % Wh/km; headwind 5 m/s at 25 km/h → +5.1× P_drag and ~+50–80 % total power; temperature from +20 °C down to 0 °C → −20–30 % usable Wh; –10 °C → −30–40 %; –20 °C → −50 %; altitude — air density ρ(h) = ρ₀ exp(−h/8400 m) gives −12 % drag at 1000 m, but motor cooling deteriorates from rarer convective air; tire pressure below 80 % nominal → +20–40 % Crr per bicyclerollingresistance.com data), a Crr table for e-scooter tires (pneumatic 0.008–0.015; foam-filled 0.020–0.028; solid honeycomb 0.022–0.035 — Cambridge UP / Design Society 2024 comparison + Wilson MIT Press inflated-tire baselines), manufacturer range testing standards (EN 17128:2020 PLEV by CEN/TC 354, UNECE R136 for L1e/L3e categories, SAE J1634 Multi-Cycle Test for EV range, WMTC worldwide motorcycle cycle), a worked example with Wh-to-km conversion, and a route-planning protocol. ENG-first sources (0 RU): Wilson MIT Press, Martin 1998, Schwalbe rolling-resistance technical notes, Bicycle Rolling Resistance Crr database, Cambridge UP / Design Society 2024 e-scooter tire study, EN 17128:2020 (CEN/TC 354), UNECE R136 e-bike type approval, SAE J1634 Multi-Cycle Test, Battery University BU-502 low-temperature discharge, NREL 2018 EV temperature derating studies, NCBI PMC9698970 Li-ion at low temperature review.

14 min read

User guide

Riding an e-scooter in wind: headwind / tailwind / crosswind / gusts — aerodynamic drag, range loss, lateral stability, route planning, Beaufort scale

Wind, for an e-scooter rider, is not a «secondary nuisance» but a separate physical axis that simultaneously hits five parameters: aerodynamic drag (P_drag = ½ρv³CdA, with ρ = 1.225 kg/m³ per ISA at sea level, and an e-scooter rider's standing-pose CdA ≈ 0.5–0.7 m² — close to the upright-cyclist values reported by Wilson «Bicycling Science» and Martin et al. 1998), range (a 5 m/s headwind at 25 km/h ground speed yields effective_v_air ≈ 32 km/h, equivalent to ~2 % gradient by the power formula, costing +20–30 % Wh/km), stopping distance (the vector sum of apparent_v with ground_v shifts effective speed entering a sharp corner with tailwind), lateral stability (lateral force F_y = ½ρv²A_side can reach ~2.5× the drag force per «Fighting crosswinds in cycling», a level that on bridges and in gaps between buildings — Venturi effect — becomes critical for 8–12-inch wheels with a short wheelbase), and gust response (transient lateral force with a 1–2 s rise time demands preemptive body posture). The wind discipline thus covers: drag-formula physics and CdA, behaviour in headwind / tailwind / crosswind / gusts, route planning around bridges / exposed stretches / coast, body posture (tucked vs upright tradeoff), gear choice (jacket flap, helmet visor) and a practical Beaufort table (Bft 0–8) with recommendations on when to ride, when to drop speed and when to dismount. ENG-first sources: Wilson «Bicycling Science», Martin et al. (1998) cycling power model, Bert Blocken (TU/e + KU Leuven) CFD studies on cyclist pose, UK Met Office and Royal Meteorological Society Beaufort scale, Fighting crosswinds in cycling (ScienceDirect), MIT urban canyon physics, BestBikeSplit / AeroX / Science4Performance CdA reference values, marsantsx / NAVEE / Apollo / Levy e-scooter range data.

13 min read