Cheat sheet
The numbers you keep looking up
Charge voltages, watt-hours per kilometre, wire gauges, gradients. Every figure here is the short version — each block links to the calculator that works it out properly for your own machine.
Battery voltages and capacity
A charger has to match the pack exactly. Series count sets every voltage in the row, and the cutoff is where the controller stops rather than where the cells die.
| Config | Nominal | Charged | Empty | Typical use |
|---|---|---|---|---|
| 10S lithium-ion | 36 V | 42.0 V | 30 V | Entry commuter scooters |
| 13S lithium-ion | 48 V | 54.6 V | 39 V | E-bikes, mid-range scooters |
| 16S lithium-ion | 60 V | 67.2 V | 48 V | Performance scooters |
| 20S lithium-ion | 72 V | 84.0 V | 60 V | High-power dual motor |
| 16S LiFePO4 | 51.2 V | 58.4 V | 40 V | Fleet and utility builds |
Capacity maths
- Wh = volts × amp-hours
- Ah = watt-hours ÷ volts
- mAh ÷ 1000 = amp-hours
- Usable ≈ 90% of the label, after BMS reserve
Always multiply by nominal voltage, never the charge voltage — using 42 V instead of 36 V overstates a 10S pack by 17%.
Flying with a battery
- Under 100 Wh — carry-on, no approval
- 100–160 Wh — carry-on with airline approval
- Over 160 Wh — not carried, cabin or hold
That last line covers essentially every scooter: even a small 280 Wh pack is nearly double the hard limit.
Watt-hours calculator converts any figure both ways · Charge time calculator reads the charge voltage off your S-count
Consumption and range
Watt-hours per kilometre is what turns a battery size into a distance. Speed moves it more than anything else you control.
| Steady speed | Consumption | Range from 500 Wh usable |
|---|---|---|
| 15 km/h | 9–12 Wh/km | 42–55 km |
| 20 km/h | 11–14 Wh/km | 36–45 km |
| 25 km/h | 14–17 Wh/km | 29–36 km |
| 30 km/h | 17–22 Wh/km | 23–29 km |
| 40 km/h | 26–33 Wh/km | 15–19 km |
Cold weather, usable capacity
- 25 °C — 100%
- 10 °C — 93%
- 0 °C — 85%
- −10 °C — 72%
Range calculator applies your weight, hills and temperature · the range guide explains why the box figure is optimistic
Power, speed and gradient
Doubling power buys about a third more speed, because drag rises with the cube of it. Gradient is the force that dwarfs everything else.
| Continuous | Flat | 10% grade |
|---|---|---|
| 250 W | 21 km/h | 6 km/h |
| 350 W | 25 km/h | 8 km/h |
| 500 W | 29 km/h | 11 km/h |
| 1000 W | 39 km/h | 21 km/h |
| 1600 W | 47 km/h | 30 km/h |
| 2400 W | 55 km/h | 39 km/h |
| Grade | Degrees | Where |
|---|---|---|
| 2% | 1.1° | Motorway gradient |
| 5% | 2.9° | Bridge approach |
| 8% | 4.6° | Wheelchair ramp maximum |
| 10% | 5.7° | Steep city hill |
| 15% | 8.5° | Car park ramp |
| 20% | 11.3° | San Francisco blocks |
Power-to-speed calculator · Hill climb calculator returns the amps and torque a gradient demands
Cells and wiring
Two numbers decide a pack: what the cells can deliver, and whether the wire between them and the controller can carry it.
| Property | 18650 | 21700 |
|---|---|---|
| Capacity | 2500–3600 mAh | 4000–5000 mAh |
| Weight | 45–48 g | 66–70 g |
| Energy density | 200–230 Wh/kg | 240–265 Wh/kg |
| Continuous | 10–30 A | 15–45 A |
| AWG | mm² | Rated |
|---|---|---|
| 4 | 21.2 | 135 A |
| 6 | 13.3 | 101 A |
| 8 | 8.37 | 73 A |
| 10 | 5.26 | 55 A |
| 12 | 3.31 | 41 A |
| 14 | 2.08 | 32 A |
| 16 | 1.31 | 22 A |
Ratings assume a single conductor in free air with high-temperature insulation. Bundled inside a sealed deck, derate by 30–50%. AWG runs backwards: smaller number, thicker wire.
Pack calculator · Wire gauge calculator · which cells to buy
Charging tiers and unit conversions
On AC the slower of charger and onboard charger wins. The speed conversions below are the ones worth memorising, because legal limits are written in both.
| Tier | Power | Range/hour |
|---|---|---|
| Level 1, 120 V | 1.2–1.9 kW | 6–10 km |
| Level 1, 230 V | 2.0–2.3 kW | 11–13 km |
| Level 2, 1-phase | 7.0–7.4 kW | 35–41 km |
| Level 2, 3-phase | 11–22 kW | 55–110 km |
| DC fast | 50 kW | 240 km |
| DC rapid | 150 kW | 700 km |
| km/h | mph | Where it applies |
|---|---|---|
| 20 | 12.4 | Germany, Italy, Japan cap |
| 24 | 15.0 | Common Canadian cap |
| 25 | 15.5 | EU light electric vehicle cap |
| 32 | 20.0 | Most common US cap |
| 45 | 28.0 | Moped class |
EV charging time · Speed converter · charging levels explained
Constants and grid intensity
The coefficients behind every performance figure on this site, and the grid numbers behind every emissions figure.
| Constant | Value |
|---|---|
| Drag area, standing rider | 0.72 m² |
| Drag area, tucked | 0.58 m² |
| Rolling resistance, city asphalt | 0.018 |
| Rolling resistance, solid tyres | 0.030 |
| Drivetrain efficiency, cruise | 75% |
| Accessory draw | 8 W |
| Air density | 1.225 kg/m³ |
| Gravity | 9.807 m/s² |
| Country | g CO₂/kWh |
|---|---|
| Norway | 30 |
| France | 60 |
| United Kingdom | 180 |
| EU average | 250 |
| United States | 370 |
| Germany | 380 |
| India | 630 |
| Poland | 660 |
Numbers for your machine
A table gets you close. A calculator gets you right.
These are round figures for a typical rider. Put your own weight, speed, gradient and tariff in and the answer changes.