UK/EU regulations dictate that an ebike must not exceed the rated power of 250W(maximum continuous rated power) to be road-legal. However when I looked at the ebikes in Halfords yesterday they were all over 300W and some over 400W. These weren't off road bikes. Can someone explain this to me.
Why many ebikes exceed UK/EU maximum of 250W
- Thread starter theo
- Start date
there is often the misconception that the instantaneous power of an e-bike motor must not exceed 250W.
The specification is not it, e-bike motors must operate reliably at the nominal power rating. It's a guarantee.
You and your bike only need 180W to 200W to ride on electric at 15mph on a flat road, so the concession for motors up to 250W makes sense. Your bike is allowed to go over the 250W nominal power temporarily when climbing hills.
The assisted speed limit of 15mph is required at all time though, so no tampering with the speed limit setting in the LCD.
Halfords website has a Raleigh Strada Elite and it says "Batterry : Shimano E6000 downtube battery 400wh ". Okay, im getting confused somewhere, arent I?
Theo, you need about 6WH to 15WH per mile, depending on how much you pedal and how hilly your terrain.
A 400WH battery (36V 11AH) gives you a range about 40 miles on average.
Batteries are the most expensive part of any e-bikes. You have to pay for the WH, so a 500WH battery will cost 25% more than a 400WH battery. Before you buy, think about how much range you want between recharge.
It's not just you. You'll often hear salesmen or even so-called technical guys at shows referring to the batteries as 400W or 13 amps instead of watt-hours and amp-hours. It's very confusing for anyone that knows basic electrics but is new to electric bikes.
Theo has simply confused motor W rating to battery W/h capacity rating which are totally different.
I live in a very hilly area. Im looking at this battery >www.yosepower.com/en/product/36V13Ah%2F16Ah-E-bike-battery-with-Carrier-fit-for-26%22-28%22-V-brake-of-rear-wheel-bike-DIY-87.html
Is it road-legal in UK?
Is it road-legal in UK?
And don't forget 1 kWh:
https://www.r-m.de/en-gb/technology/dualbattery/
Definition of Wh:
https://whatis.techtarget.com/definition/watt-hour-Wh
https://www.r-m.de/en-gb/technology/dualbattery/
Definition of Wh:
https://whatis.techtarget.com/definition/watt-hour-Wh
Any 36v or 48v nominal battery is legal to use irrelevant of how many Ah or Wh capacity is used, on a long run I can carry 1500wh if I wish to.
For an idea of rough range from a battery a rider will use between 10 - 20 wh per mile so divide the upper figure for a worst case scenario of range by the battery Wh rating.
So 500Wh divide by 20Wh/m = 25 miles range, if a fit rider then range can be far greater and even more if you only use assist for inclines/hills.
For an idea of rough range from a battery a rider will use between 10 - 20 wh per mile so divide the upper figure for a worst case scenario of range by the battery Wh rating.
So 500Wh divide by 20Wh/m = 25 miles range, if a fit rider then range can be far greater and even more if you only use assist for inclines/hills.
That's very pedantic. I just picked out two random common capacities, one in each units. They're not related.
Funnily enough, as I wrote it, I was sure that someone was going to misinterpret what I wrote and pull me up on it, but let it ride to see if I was right.
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I think it is helpful to be pedantic about watts, watt-hours etc. Especially as the original post arose at least partly from confusion about those units. Many people (probably including the OP) are very reasonably rather hazy on such details, and it is very difficult to become clear when the basic principles are confused by misuse of units.
Correct, but I think you've misunderstood the point. Woosh was implying that my maths was wrong (maybe trying to reinforce a point from another thread). I didn't say or imply that 400Wh and 13Ah were equivalent. I was simply comparing watts with watt-hours and amps with amp hours in the same sentence. If I had written an additional 400 in front of watt-hours and 13 in front of amp-hours, it would have been more obvious, but it makes clumsy reading like that.
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we're just getting old. I bet when you were at school, you could do multiplications and divisions in your head but not anymore.
The current UK laws on this subject really need repealing. I can understand the reasons why a one eyed granny shouldn't do 40mph on a shared path, but for an average sensible cyclist on the road common sense should prevail.
Battery capacity, voltage or motor wattage shouldn't come into the equation anyway, that doesn't affect the speed chosen by the rider, merely the potential available.
I doubt if any cyclist, electric or not, could be successfully prosecuted for exceeding a speed limit as there is no requirement for a speedometer therefore no means of monitoring it.
Throttle control should also be legal not just to assist those with certain disabilities but what difference does having to peddle make anyway. In the early 1970's the laws were changed on mopeds removing the requirement of peddles and introducing a maximum design speed of 28mph. Maybe as pedelecs become more popular, there is a danger of new legislation being introduced to bring them into line with mopeds so they can be easily controlled?
Battery capacity, voltage or motor wattage shouldn't come into the equation anyway, that doesn't affect the speed chosen by the rider, merely the potential available.
I doubt if any cyclist, electric or not, could be successfully prosecuted for exceeding a speed limit as there is no requirement for a speedometer therefore no means of monitoring it.
Throttle control should also be legal not just to assist those with certain disabilities but what difference does having to peddle make anyway. In the early 1970's the laws were changed on mopeds removing the requirement of peddles and introducing a maximum design speed of 28mph. Maybe as pedelecs become more popular, there is a danger of new legislation being introduced to bring them into line with mopeds so they can be easily controlled?
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