Approved ebike list?

[flecc]

There's no doubt about the industry support for consumers on this issue, but of course that can only be for e-bikes that are UK or EU legal, with some tolerance on the throttle with 250 watt issue. I can't see an issue ever getting as far as this legal action though. Government cannot ever admit to condoning illegality or circumventing the law, but they do so all the time and would no doubt do some rule bending if the occasion arose.

 

[Jeremy]

In case anyone is interested, I've just plotted the curve of power and acceleration time over 20m for a 150kg total bike weight, as described in Annex D of EN15194 as an acceptable means of showing compliance with the 250W power limit.

The red line is the 250W limit and if you look at the plot you can see that an EPAC needs to take at least 7.83 seconds to cover 20m from a standing start (on level ground with little wind) in order to be shown to have no more than 250W.

Note also that if you add a power application delay, say you just slow down the controller response time to a demand for more power, then this has the effect of moving that curve (and the vertical red line) to the left. For example, if you added a 2 second delay ramp to the controller input then the continuous power output would really be about 600W, yet the test would give a result of 250W.

If you wanted to be more extreme, then making the controller acceleration ramp 3 seconds would allow you to have well over 1kw, yet it would still legally be a 250W EPAC.

Curious way to frame a set of rules, but I suppose they must have had their reasons for doing it this way.

 

[Miles]

Curious way to frame a set of rules, but I suppose they must have had their reasons for doing it this way.

Thanks for the graph Jeremy.

Curious but it makes more sense than 250W cont. power. At least acceleration rate could be argued to have some relation to safety...

What happens with bikes which have the motor acting through variable gearing, though? If they're tested at the gear that peaks at 25kph, then..........

Anyway, it's certainly an incentive to be relaxed and lose weight : )

 

[flecc]

What happens with bikes which have the motor acting through variable gearing, though? If they're tested at the gear that peaks at 25kph, then..........

Many if not most are like the Panasonic system, pedelec only and with encapsulated circuitry unable to be run with a fully acting throttle. They won't be subjected to the acceleration method of determining power. Consumption graphs show that the Panasonic unit at least cannot be delivering more than 250 watts average, and the delivery peaks are intermittent by pedal thrust torque sensing so arguably not continuous.

 

[Miles]

I guess I was thinking of the acceleration test with regard to DIY bikes.

Weight and speed would be a much more sensible way to go but I just don't see it being accepted, somehow.. There are too many people who use power as a fear factor not to have it tested for, in some way....

 

[Old_Dave]

If we don't succeed with the 1 2 3, then If a bike ever had to be presented for inspection, then the acceleration test as proof of conformity is a silver lining in the cloud..


Sent from my iPhone using Tapatalk

 

[Jeremy]

Many if not most are like the Panasonic system, pedelec only and with encapsulated circuitry unable to be run with a fully acting throttle. They won't be subjected to the acceleration method of determining power. Consumption graphs show that the Panasonic unit at least cannot be delivering more than 250 watts average, and the delivery peaks are intermittent by pedal thrust torque sensing so arguably not continuous.

They could be though. The EN allows the circuitry to be modified to allow the pedelec system to be disabled and for the bike to run on electric assist only for the test:

"The test shall be performed without pedalling using only the electrical assistance system (the test bicycle shall be prepared accordingly)."

It is therefore OK to modify the bike so that the torque sensor is disconnected and replaced with an input to the controller that simulates it and allows the electric motor to run as if it were being pedalled. This opens up all sorts of interesting ways to perform the test, if you have a bit of imagination...............

 

[flecc]

This opens up all sorts of interesting ways to perform the test, if you have a bit of imagination...............

It certainly does!

I doubt if anyone would bother on the type of system I mentioned though, since it complies on power alone anyway.

 

[tillson]

Note also that if you add a power application delay, say you just slow down the controller response time to a demand for more power, then this has the effect of moving that curve (and the vertical red line) to the left. For example, if you added a 2 second delay ramp to the controller input then the continuous power output would really be about 600W, yet the test would give a result of 250W.

If you wanted to be more extreme, then making the controller acceleration ramp 3 seconds would allow you to have well over 1kw, yet it would still legally be a 250W EPAC.

Curious way to frame a set of rules, but I suppose they must have had their reasons for doing it this way.

An interesting graph, thanks for posting. The method certainly leaves scope to provide the bike with a useful amount of power, whilst at the same time allowing it to comply with the regulations. A glimmer of common sense.

I can see how the Panasonic and Bosch systems can be used in conjunction with the bike's gearing to skew the results even more favourably.

 

[Jeremy]

I've been playing around further with applying a linear power ramp and if, for example, you applied power from a standstill at an increasing rate of 40% per second (so 0% initially, 40% after 1 second, 80% after 2 seconds and 100% after 2.5 seconds and then held at 100% for the remainder of the test) then you could have just under 600 W continuous power, but the test results would give a power of 250 W.

I strongly suspect that you might not notice a ramp like this on a pedelec, in fact it might feel smoother than having 100% at the first turn of the pedals, as some systems seem to give. There's no doubt that 600 W continuous power would give a helpful boost on even the steepest of hills.

 

[Scimitar]

So, if the bike is illegal either way - I might as well make it worth it eh?

Well, you can't be 'a little bit' pregnant. May as well be hung for a sheep, as they say in some parts.

 

[Scimitar]

My guess is that the majority of cyclists have no form of third party insurance cover.

An ebike that has a performance similar to that of a pedal cycle presents no more risk to the general public.

How often do we hear of cyclists being sued for injury damage (or pedestrians pushing prams, or people riding mobility scooters, or propelling wheelchairs, come to that)?

We don't hear about it much, because it doesn't happen much. There's a general public perception that cyclists don't have insurance, as you say, and so aren't worth pursuing for a claim.
That will change if insurance becomes much more common - the shiny sharkskin suits will cruise the waters sniffing blood - you know who I mean. Them and their turd-brown plasticene dogs on the telly.

For the sake of argument, if someone was convicted of driving without insurance and driving without a licence or in contravention of a court disqualification on an EU-legal bike then I would sincerely hope that everyone in the industry would rally round to fund the cost of them suing the government for negligence over being in breach of the terms of 2002/EC/24.

You're 'avin' a larf. Put their hands in their pockets? Hhahahaha.
Never happen, mate.

 

[shemozzle999]

Would a physical maximum weight limit on a 250W hub motor help to describe it in law so that it excludes the blatantly over powered units, eliminating the need for it to be tested at all?
It will also make it easier for repair/replacements to be fitted if the original unit becomes obsolete.

 

[Jeremy]

Would a physical maximum weight limit on a 250W hub motor help to describe it in law so that it excludes the blatantly over powered units, eliminating the need for it to be tested at all?
It will also make it easier for repair/replacements to be fitted if the original unit becomes obsolete.

Probably not, unfortunately. If you spin a small motor at a higher rpm then you can get more power out of it for a given torque (torque being proportional to current and current being the primary limiting factor in terms of generating heat in the motor). Some of the smallest, highly geared, hub motors can comfortably exceed 250W. For example, Justin has recently tested the little Tongxin motor and it will sustain about 350W continuously without overheating. The Cute Q100 is about the same. AFAIK, these are about the smallest hub motors available, yet are both capable of well over the nominal 250W limit.

There's also the issue of non-hub DIY drives. The tiny little Australian made Commuter Booster, for example, only weighs around 1kg yet can deliver well over 250W, I think the most powerful version will deliver a couple of kW.

 

[103Alex1]

The tiny little Australian made Commuter Booster, for example, only weighs around 1kg yet can deliver well over 250W, I think the most powerful version will deliver a couple of kW.

That looks like just the job to fit to a road bike and tune up the power .

 

[amigafan2003]

Would a physical maximum weight limit on a 250W hub motor help to describe it in law so that it excludes the blatantly over powered units, eliminating the need for it to be tested at all?
It will also make it easier for repair/replacements to be fitted if the original unit becomes obsolete.

I really don't think we should be accepting a 250w motor as the norm.

Rather, we should be pushing for the legislation to allow higher power units upto 750w (as with our American cousins) should be what we strive for.

I know the EU have already knocked it back - doesn't mean they are right though.

 

[TwoBikes]

Furthermore, the EU type approval order 2002/EC/24 was passed into UK law on 10th November 2003 as instructed by the EU commission.

Actually it didn't pass into UK law until 11.12.2006, under Statutory Instrument 2006/2935.

This not only mentions the legality of 250 watt pedelecs,

It only mentions this in a negative sense, saying that the regulations don't apply to electric cycles below this power (amongst other things).

it also instructs member governments to remove all conflicting legislation by that date,

I have read and re-read these regulations and cannot find the clause that requires removal of conflicting legislation. I have seen such a clause in other regulations though. Anyway, the traditional UK regulations from 1983 don't conflict with the EU ones. They create an overlap that clearly requires some electric cycles that are authorised under the UK regs to be type-approved after 2006.

 

[shemozzle999]

I suspect overpowering for a prolonged period during real life testing of smaller units would cause core saturation, reducing efficiency and increasing over heating, creating self limiting power outputs, if motor failure is to be avoided.

 

[Jeremy]

That looks like just the job to fit to a road bike and tune up the power .

From what I can gather it's pretty much ideal for a light road bike. Adrian's web site is here: https://sites.google.com/site/commuterbooster/

 

[Jeremy]

I suspect overpowering for a prolonged period during real life testing of smaller units would cause core saturation, reducing efficiency and increasing over heating, creating self limiting power outputs, if motor failure is to be avoided.

The main problem isn't saturation (as that's driven by AT, so determined largely by current) but the ability of a small motor to get rid of heat. However, this can be improved, as many of the smaller hub motors aren't well designed in terms of providing a good thermal path from the windings to ambient. If someone wanted to improve the continuous power handling capability of such a small motor, then something like adding fluid cooling might well get around double the current power limit.