E bike conversion

Electrically assisted bikes, trikes, etc.
CXRAndy
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Re: E bike conversion

Postby CXRAndy » 19 Aug 2019, 7:32am

Only if I program it to exceed 15.6mph.

hemo
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Location: West Sussex

Re: E bike conversion

Postby hemo » 19 Aug 2019, 9:10am

CXRAndy wrote:Only if I program it to exceed 15.6mph.


Sorry not true.
The fact it is 52v nominal makes it illegal and I suspect the power rating is 500 or 750w unless the custom fudge includes the marking it with a 250w label, on both accounts it is not legal unless solely used on private land with no public access what so ever.

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hoarder
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Re: E bike conversion

Postby hoarder » 19 Aug 2019, 9:43am

hemo wrote:
CXRAndy wrote:Only if I program it to exceed 15.6mph.


Sorry not true.
The fact it is 52v nominal makes it illegal and I suspect the power rating is 500 or 750w unless the custom fudge includes the marking it with a 250w label, on both accounts it is not legal unless solely used on private land with no public access what so ever.


Sorry, but to avoid confusion: is it the 52v that makes it illegal, or being more than 250w motor power ?

stodd
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Joined: 6 Jun 2018, 10:24am

Re: E bike conversion

Postby stodd » 19 Aug 2019, 10:55am

Either >250w (nominal) or >48v (nominal) make a bike break the EAPC regulations.
Almost all 250w motors can deliver much more than that. Also, most batteries fully charged actually have a higher voltage than their nominal value.

kwackers
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Location: Warrington

Re: E bike conversion

Postby kwackers » 19 Aug 2019, 11:13am

stodd wrote:Either >250w (nominal) or >48v (nominal) make a bike break the EAPC regulations.
Almost all 250w motors can deliver much more than that. Also, most batteries fully charged actually have a higher voltage than their nominal value.

I wonder why there's a cap on battery voltage.
Safety?

Can't think of any other reason.

Vernon6026
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Joined: 19 Aug 2019, 9:14am

Re: E bike conversion

Postby Vernon6026 » 19 Aug 2019, 11:14am

Greenbuilder wrote:Can I recommend a crank drive motor, such as this Bafang BBSO2 which I've fitted to my 27.5 hardtail.
Easy to fit, low centre of gravity and the bike pedals fine with it turned off. I put a big 15ah battery on, which lasts 4-5 hours off road, but a 9ah would be ok and much lighter. I used to ride hub motor bikes, but these are much better.IMG_20190411_114944.jpgI


Hi sorry to bother you , I am interested in converting my bike which is a specialised sirrus hybrid ?

Can you possibly give some info how to do this at all ?

Regards

stodd
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Re: E bike conversion

Postby stodd » 19 Aug 2019, 11:34am

I think all the parts of the rules are safety in some sense. Some bits may feel a little silly, but it is very difficult to write rules that make a clear dividing line. It is quite difficult to find details of the rules. I found the 48v bit on the pedalecs forum. (usually reliable but maybe wrong in this case???)

I have been chasing a bit more just out of general interest, even the DoT sheet does not mention it specifically (https://assets.publishing.service.gov.u ... cycles.pdf) but refers to The Electrical Equipment designed for use within certain Voltage Limits Directive 2006/95/EC (commonly known as the Low Voltage Directive) with a broken link. Attempts to search indicate that is for items with DC voltage between 75 and 1000v.

stodd
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Re: E bike conversion

Postby stodd » 19 Aug 2019, 11:38am

Hi sorry to bother you , I am interested in converting my bike which is a specialised sirrus hybrid ?
Can you possibly give some info how to do this at all ?

You will probably get good advice on https://www.pedelecs.co.uk/forum/forums ... ussion.42/

CXRAndy
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Joined: 18 Aug 2019, 1:45pm

Re: E bike conversion

Postby CXRAndy » 19 Aug 2019, 12:24pm

Im not concerned, the figures are arbitrary in my opinion.

its not used for bombing along at 20+ mph. The battery and settings are for range, so my wife can do a nice ride and feel assured that there will be enough battery to get her back home.

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hoarder
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Re: E bike conversion

Postby hoarder » 19 Aug 2019, 2:07pm

CXRAndy wrote:Im not concerned, the figures are arbitrary in my opinion.

its not used for bombing along at 20+ mph. The battery and settings are for range, so my wife can do a nice ride and feel assured that there will be enough battery to get her back home.


OK, I'm more interested in range and ability too, rather than speed.

So, if the speed sensor fitted to the bike ensures the motor never powers the bike to exceed ~16 mph, then why has 250W been chosen as the ceiling for power input ? Am I right to think that heavier riders risk having to get off and walk on steep inclines with a 250w motor, but with an identical battery, a more powerful controller and motor would still keep them cycling ?

CXRAndy
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Re: E bike conversion

Postby CXRAndy » 19 Aug 2019, 2:54pm

There is alot of bluff going on with power numbers and speed limits.

250 Watts is bandied around, but no one says whether this is peak or constant power capability. A lot of these motors are capable of way more in power terms

Speed again is varied, 25kph (15.6 mph) but quite a few bikes easily go above before assist cuts out. Why 15.6 mph? USA has 20 mph cut off. My wife rides with me between 14-16 mph and has a range of 100+ miles. She can ride into a headwind by upping the assist level better than I can and climb gradients faster. My wife can ride faster than the assist level and power drops to zero. Does that make her bike more dangerous because she can ride faster with or without assistance? In my opinion, no

It lowers her physical effort to be able to ride longer and enjoy the outing.

Using a higher voltage and large amperage battery, stress on the motor can be reduced by lowering the current demand to attain a certain power.

Manufactured ebikes are actually quite limited in range if you're not very fit, because the rider demands more of the assist.

Custom allows for greater range and performance without being crazy also in many cases using your current bike for not much outlay in cost

stodd
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Re: E bike conversion

Postby stodd » 19 Aug 2019, 3:03pm

Yes the 250w limit is arbitrary, particularly as it is a limit on continuous power and not on max power.

Some limit is necessary to go with the privilege of being able to ride on road without license, tax and insurance, and to ride on bridleways. There are those that say any bicycle on the road (electric or not) should require all those. At the other extreme there are those that feel it an imposition of their liberty that they can't ride a 2l motor bike without them, or to drive an SUV on any bridleway. The law is trying to strike a sensible balance between those; but yes it is an arbitrary balance.

With suitable gearing a typical 250w motor should get a 150kg of bike + rider up a 15% hill. (You can check out details at https://www.ebikes.ca/tools/simulator.html)

hemo
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Location: West Sussex

Re: E bike conversion

Postby hemo » 19 Aug 2019, 5:28pm

The 250w law on power rating and speed is originally from Japan and the EU harmonised with them and believe it was the old reliable Panasonic hub motor that was used.
Most motors produce more then 250w because there is no current/ampage limit on controllers used.
The test for a legal badged 250w motor is that it can be run continuoulsy for 1 or 2 hrs with out over heating at 250w/6.94a for a 36v motor and 5.2a for a 48v motor (oboviously there is a temp range it has to fall within). A more powerful wound motor dosen't like to run at the same speed as the 250w one so it would suffer from temperature rise and thus would be proven not to be a 250w rated motor.

Currently the only likely situation that a motors nominal power may be questioned is if stopped by Plod or someone is involved in a an accident and Plod are involved.

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al_yrpal
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Re: E bike conversion

Postby al_yrpal » 21 Aug 2019, 2:46pm

There are a couple of hills around here that I struggle on with my Bosch Performance powered E Bike. Me and the bike are about 110kg and even in the lowest gear with Turbo assistance and me standing on the pedals its a struggle! Must be 1 in 4 or more.

Al
Touring on a bicycle is a great way to explore and appreciate the countryside and towns you pass through. What do you do to make a difference?