E-bike range explained: watt-hours, and what you will actually get

A watt-hour is one watt drawn for one hour. It is a quantity of energy, which is exactly what a fuel tank holds, and it is the only battery number worth comparing across brands. The batteries in this catalogue run from 500 Wh to 750 Wh.

Ignore amp-hours on their own. A 14 Ah battery means nothing until you know the voltage: watt-hours are volts multiplied by amp-hours, so a 36 V 14 Ah pack is 504 Wh and a 48 V 14 Ah pack is 672 Wh. If a listing quotes only amp-hours, do the multiplication before you compare.

The usable rule of thumb, and it is a rule of thumb rather than a specification: on flat ground with moderate assist, an adult on a normal e-bike uses roughly 7 to 10 Wh per kilometre. On hilly ground, or at high assist, or carrying a load, it rises to roughly 12 to 20 Wh per kilometre. Ride at maximum assist into a headwind up a hill and you can exceed that.

Put the catalogue through it. A 500 Wh battery at 8 Wh/km gives about 62 km. A 750 Wh battery at the same rate gives about 94 km. That is why the honest assisted range quoted for the eight e-bikes here — from the Aventon Level.2 at €1,899 to the full-suspension bikes at €5,499 — is 60 to 100 km, and why the same bikes can return half of that on a bad day in February.

1. 1

   Start with the battery

   Take the watt-hour figure from the spec sheet — 500 to 750 Wh across this catalogue. If only amp-hours are given, multiply by the voltage.

2. 2

   Pick your consumption band

   Flat and moderate assist: 8 Wh/km. Rolling terrain or a loaded commute: 12 Wh/km. Steep hills, heavy load or high assist throughout: 18 Wh/km.

3. 3

   Divide

   Watt-hours divided by watt-hours per kilometre. A 625 Wh battery on rolling terrain at 12 Wh/km comes out at roughly 52 km.

4. 4

   Take 20% off for the reserve

   Nobody wants to arrive at zero, and the last stretch of a battery is where the display becomes least trustworthy. That 52 km becomes about 42 km of route you would actually plan.

5. 5

   Halve it if you must return

   A round trip with no charge at the far end means your planning distance is half the figure above. This is the step people forget, and it is the one that strands them.

1. Assist level. The largest single factor by a distance. Dropping from the top setting to the middle one can add half again to your range, because the motor is asked for less at every pedal stroke.
2. Rider and cargo weight. Every kilogram has to be accelerated from every set of traffic lights and lifted up every hill. A 15 kg load on a hilly commute is a real, noticeable cost.
3. Terrain. Climbing is work that must be paid for in energy. Descending gives only a little of it back. A hilly route can double consumption against the same distance on the flat.
4. Wind. A headwind is a hill that never ends. It is also the factor riders most often blame on the battery instead.
5. Temperature. Lithium-ion cells deliver less usable capacity when cold. Expect noticeably less range near freezing — plan on a fifth to a third less, and store the battery indoors so it starts warm.
6. Tyre pressure. A soft tyre costs energy on every rotation. Check it weekly against the range on the sidewall; tyre width and pressure explains where in that range to sit.
7. Stop-start riding. Each acceleration from rest is paid for in full. A city commute with twenty junctions uses more than an open road of the same length at the same speed.

Six of those seven are under your control on any given ride. That is the useful part: if you arrive somewhere with less battery than you expected, the fix is usually the assist level and the tyre pressure, in that order, not a bigger battery.

Published range figures are produced on a test rig or a controlled route, with a light rider, the lowest assist setting, mild temperature, correct tyre pressure and no stopping. They are not dishonest — they are repeatable, which is the point of a standard test — but they describe conditions you will never ride in.

Treat a single headline number as the ceiling. Where a maker publishes a range span rather than one figure, the low end is the useful one. Better still, use the arithmetic above with your own weight and your own route, then check it against your first month of riding.

For the eight e-bikes in this catalogue the honest assisted figure is 60 to 100 km, from batteries of 500 to 750 Wh. That is a real-world number, and it is the one worth planning around whichever bike you end up on — see the full e-bike shortlist or start from your route in the finder .

E-bike packs are lithium-ion, and manufacturers typically rate them for several hundred to around a thousand full charge cycles before capacity falls to roughly 70–80% of new. A cycle is a full battery's worth of energy, not a plug-in: two half-discharges count as one. Ordinary commuting use therefore takes years to reach it.

• Charge at room temperature. Do not charge a battery that has just come in from below freezing — let it warm up first.
• For storage over a month or more, leave it around half charged, indoors, somewhere cool and dry. A pack left full or left flat for a season ages faster.
• Partial charges are fine and mildly preferable. There is no need to run it flat, and no benefit in doing so.
• Use the charger that came with it. Cheap third-party chargers are the most common cause of battery damage and of fires.
• If a pack is swollen, damaged, or has been in a crash, stop using it and take it to a dealer. Do not charge it and do not open it.

A battery is a consumable with a long life, not a permanent part. Ask the replacement price before you buy the bike — it is the largest single cost in owning one, and the answer varies enormously between brands.

The decision rule: if you are still choosing the bike, buy the larger battery. If you already own the bike, a second battery is the flexible answer, because it also doubles as a replacement when the original loses capacity — and it must be the same pack from the same maker, since batteries are not cross-compatible. The reasons for that lock-in are in e-bike motors explained .

And one honest alternative: if the shortfall is only occasional, a lighter unassisted bike for those rides may serve you better than a second pack. The unassisted bikes here have a median price of €1,600 against €4,299 for the e-bikes — see how to choose a bike before you commit to a second pack.