Le Petit PorteurLongtail

The battery = the tank

Its capacity is measured in watt-hours (Wh): voltage (V) multiplied by amp-hours (Ah). More Wh means more kilometres between charges, but neither more speed nor more power.

The motor = the strength

What matters is torque, in newton-metres (Nm): it makes the difference when setting off, on hills and with children or a load. For an electrically assisted bicycle, European law limits power to 250 W and cuts assistance at 25 km/h: maximum assisted speed is therefore the same for all; a higher-torque motor reaches it more easily, even when loaded.

Range = your use

With the same battery, range varies a lot depending on the assistance level chosen (from Eco to Turbo), hills, the weight carried, average speed, wind, tyre pressure and cold weather, which reduces capacity.