SUNNIGOO Guides & E-Scooter Reviews

SUNNIGOO B4 folding fat-tire e-bike with 20x4.0 inch tires and full suspension

SUNNIGOO Guides & E-Scooter Reviews

E-Bike Range Explained 2026: Wh Maths, Assist Levels and Real vs Claimed Range

door SUNNIGOO Editorial Team op 15 okt. 2026
European riders asked more questions about e-bike range in 2026 than about any other specification, and the reason is simple: the number printed on the box rarely matches the number on the trip computer. If you are comparing folding fat-tire models, start with the SUNNIGOO electric scooters collection and the electric bicycles collection, then read the battery maths below before you buy. Two hard numbers frame the discussion. First, Germany's bicycle industry association ZIV reported on 7 September 2026 that e-bike production rose 4% and e-bike sales 2% in the first half of 2026, with manufacturers confirming that excess stock built up in 2024–25 has largely cleared — meaning 2026 buyers are looking at current-generation batteries, not old warehouse stock. Second, and less comfortably for marketing departments, the United States-based Battery University's BU-504 reference measures lithium-ion capacity loss at roughly 17% at 0 °C, 34% at −10 °C and 47% at −20 °C, which is why a battery that delivers 80 km in September can deliver far less in January. What "600 Wh" Actually Means Watt-hours are the only battery figure that predicts distance. Amp-hours alone are meaningless without voltage, because a 12.5 Ah pack at 24 V holds half the energy of a 12.5 Ah pack at 48 V. The formula: Wh = volts × amp-hours The SUNNIGOO B4 carries a removable 48 V 12.5 Ah lithium pack: 48 × 12.5 = 600 Wh. That is the size of the fuel tank. Distance then depends on how quickly you empty it, measured in watt-hours per kilometre. Work the maths backwards from the claim The B4 is specified at 50–80 km in pedal-assist mode. Divide 600 Wh by that range and you get the consumption the manufacturer's claim implies: 7.5 Wh/km at the optimistic end (80 km) and 12 Wh/km at the conservative end (50 km). Any riding condition that pushes consumption above roughly 12 Wh/km will land you below 50 km. That single calculation lets you sanity-check every range claim on the market — a 360 Wh bike advertised at "up to 100 km" is claiming 3.6 Wh/km, which no production e-bike achieves. The Variables That Move the Number Bosch's official range calculator asks for exactly the inputs that matter, which is the clearest published list of what range depends on: battery capacity in watt-hours, assist mode, total weight of rider and luggage, cadence, terrain profile, surface, tyre tread, wind, ambient temperature, how often you stop and start, and your average speed. Two of those deserve special attention on a fat-tire bike. Assist level is the biggest lever you control Pedal-assist levels change how much of the work the motor does. In the highest assist mode the motor covers most of the effort and consumption climbs; in the lowest mode you are effectively riding a heavy bicycle with a helpful push, and consumption drops sharply. Bosch's own battery guide describes "favourable" conditions as a total system weight up to 105 kg, a cadence of 50–70 rpm and a touring-bike posture, and "difficult" conditions as up to 150 kg, 70–90 rpm, mountain-bike geometry and low-mountain terrain — the same battery covers a very different distance in those two scenarios. Tyres, temperature and stop-start traffic Wide 20 × 4.0 inch fat tyres are the reason a bike like the B4 stays stable on cobblestones, gravel and wet leaves, but a larger contact patch and aggressive tread cost energy on smooth tarmac. Cold compounds the effect: capacity is temporarily reduced at low temperature and recovers when the pack returns to room temperature, and charging a lithium pack below freezing is prohibited because of lithium plating. Practically, that means a winter commuter should plan around the lower half of the claimed range and store the removable battery indoors overnight. Why 250 W and 25 km/h Are Not Limitations Power figures on e-bikes are regulated, not chosen. Under Regulation (EU) No 168/2013, Article 2(2)(h), cycles with pedal assistance, a maximum continuous rated motor power of 0.25 kW, and motor output that cuts off when the rider stops pedalling and progressively reduces before 25 km/h, are excluded from type-approval requirements. That exclusion is what keeps a pedelec legally a bicycle rather than a moped. What that means in Germany In Germany the consequence of that EU definition is straightforward: a 250 W / 25 km/h pedelec is treated as a bicycle, so there is no registration, no insurance plate and no type approval to chase. The ABE (Allgemeine Betriebserlaubnis) regime that German riders associate with e-scooters belongs to the eKFV regulation for electric micro-vehicles and is administered by the Kraftfahrt-Bundesamt — it is a separate track from e-bikes. Among SUNNIGOO's scooter line-up, the N5 is the model built to that German e-scooter approval; high-power scooters are a different legal category again. The B4, as a 250 W pedelec with a 25 km/h cut-off, sits in the bicycle category. Reading the spec sheet honestly So when you see "250 W" next to a competitor's "1000 W" claim, check which standard each number refers to. A motor rated 250 W continuous under the EU pedelec definition is a compliance statement, not a weakness; claims above that place the vehicle outside the pedelec class in most of the EU, which brings registration, insurance and helmet obligations with it. What 600 Wh Buys You in Practice Put the B4's numbers into a weekly commuting ledger. At the conservative 12 Wh/km figure, 600 Wh covers about 50 km — roughly five days of a 10 km round trip, or a full week for a 7 km daily return commute, before you plug in. At the efficient 7.5 Wh/km end, the same pack covers 80 km, which is a weekend ride plus two commuting days. Riders who sit between those extremes, with a mix of assist levels and moderate terrain, will typically land in the middle of the 50–80 km band. Price and the current offer The B4 is listed at €1,079, reduced from €1,329, and includes full suspension, 20 × 4.0 inch fat tyres, a 7-speed drivetrain and the removable 600 Wh battery. Readers who join the newsletter receive code EBIKE10 for 10% off the electric bicycles collection, one use per customer. Conclusion E-bike range is arithmetic, not marketing: take the watt-hours, divide by realistic consumption of roughly 7.5–12 Wh/km, and subtract for cold weather, high assist levels and stop-start traffic. The B4's 600 Wh pack and 50–80 km claim fit that model, which is the most practical test you can apply to any e-bike before buying. FAQs 1. How do I calculate e-bike range from a battery spec? Multiply volts by amp-hours to get watt-hours, then divide by your consumption in watt-hours per kilometre. A 48 V 12.5 Ah pack is 600 Wh; at 7.5–12 Wh/km that gives 50–80 km, which is exactly the range band SUNNIGOO specifies for the B4. 2. Is 250 W enough power for a fat-tire e-bike? Yes for the category the B4 is built for. Regulation (EU) No 168/2013 Article 2(2)(h) defines the pedelec class at 250 W continuous with assistance cutting off before 25 km/h, and that is what keeps the bike in the bicycle category instead of the moped category. Higher figures move the vehicle into a different legal class in most EU countries. 3. How much range do I lose in winter? Battery University's BU-504 reference measures capacity loss of about 17% at 0 °C, 34% at −10 °C and 47% at −20 °C. The loss is temporary and recovers at room temperature, but you should never charge a lithium pack below freezing. Storing the removable battery indoors is the cheapest winter range insurance there is. 4. Does an e-bike need ABE approval in Germany? No. ABE belongs to the eKFV regime for electric micro-vehicles such as e-scooters and is issued and listed by the Kraftfahrt-Bundesamt. A 250 W / 25 km/h pedelec is excluded from type approval under EU law and is treated as a bicycle, with no registration, insurance plate or helmet mandate. People also ask: Folding e-bike size comparison 2026: B1, B3, B4, B5 and C91 X10 flagship deep dive: 6000W and 100 km range explained Deutschlandticket 2027 price rise vs the cost of riding your own scooter About SUNNIGOO: SUNNIGOO is a European brand manufacturer of electric scooters and e-bikes, with warehouses in Germany, Poland and France and a service centre in Messel, Germany. E-scooters are built to CE EN 17128, every model carries a 2-year warranty on motor and frame, and European delivery takes 3–7 working days.