New to all this! About to get an e-bike and insurance

matthewslack

Esteemed Pedelecer
Nov 26, 2021
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Perhaps it is measuring cutoff speed rather than power...
 
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thelarkbox

Esteemed Pedelecer
Aug 23, 2023
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oxon
Perhaps it is measuring cutoff speed rather than power...
Quite possibly, after all cycles in the uk are not bound by speed limits on the rds perhaps dutch law is similar and also worded such that testing for speed directly is not possible..
 

Fatgadget

Pedelecer
Aug 22, 2011
29
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Fake news.
Really? I saw a posting on Endless Sphere not that long ago .... From a Dutch subscriber.
Either way,PC Plod in Central London DO check the power output of leccy bikes with Watt meters!....Ask me how I know!
 
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thelarkbox

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Aug 23, 2023
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saneagle

Esteemed Pedelecer
Oct 10, 2010
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Ironic isn't it just!...I have an ancient 250W (labelled) motor on my bike that has been happily taking all of half a killowatt I been throwing at it the past 5 years or so! What PC Plod have been doing of late though; is targeting those humongous unbranded motors AND equally huge battery packs.....incidentally, I might well know your friend with Rickshaws!...Which part of London?...I'm based in Camden.
The pedicabs were Maxpro brand. My association was with the manufacturer, who asked for my help. I didn't really know the fleet owner, who was called Adam. Here's the main part of the letter I wrote:

"Here's some points that will help your lawyer:

1. From your description of what the police did (using a clamp-type current meter), they have used an invalid measuring method for the motor output power.

They have measured the power coming out of the battery, which has no direct relation to the power coming out of the motor.

The power coming out of the battery goes into the motor controller, which converts it into pulsed electrical power that it sends on to the motor. There is a conversion efficiency that has not been determined, but it's certain that less power will come out of the controller than what goes into it. You should ask the police, which numeric numer they used for the controller's conversion efficiency.

The mechanical power coming out of the motor has no direct relation to the power going in because again there is a conversion efficiency, but in this case, the value would vary between 0% when the motor is stalled to something like 75% when running in optimum conditions. The main factor that affects the motor's efficiency is its rotation speed. At low speed, it's extremely inefficient (say 25%) and at normal running speed, it would be about 70%. Again you should ask what the conversion factor the police used and at the speed that the motor was turning when they measured it. This has to be the actual motor speed, not the wheel speed.

The motor will take the most current from the battery when it's running at its lowest speed when it's least efficient. As the motor speed increases,the current decreases because the motor generates a back electro-motive force (voltage) in proportion to its speed, which effectively reduces the battery battery voltage and, as current is proportional to voltage, the current goes down and so does the power as the motor speeds up.

In other words, it's virtually impossible to give a figure for output power based on measurement of the current coming from the battery, even if you knew the motor's speed at the time of measurement.You would have to plot it on a graph of the actual motor's efficiency - if you had one.

The only way to measure a motor's output power is to put the vehicle on a dynamometer - normally a rolling road type.

2. The police used an incorrect standard for what's allowed in a pedelec type vehicle. The government's website along with many other guides are incorrect, in that they state that the maximum output power is 250w. That's not UK law.

The UK pedelec regulations were harmonised with the European standard EN15194. The date that happened is very complicated. Some argue that it was effective from 2009, when the directive was made, but I think it was finally done in 2015. Either way, it's effective now. In EN15194 latest version *(2017), the wording is "electrically power assisted bicycles of a type which have a maximum continuous rated power of 0.25 kW.
There are two key words in that statement. Firstly, it's the "rated" continuous maximum power. The vehicle' rating is done by the manufacturer. There is no regulation, nor standard for how a motor should be rated and the rating is independent of peak output power. EN 15194 refers to a test for motor rating, but that test is to insure that the motor isn't overrated. It's basically a pass of fail on whether the motor overheats.

The second key word is "continuous", which is different to peak power. The police measured peak power. That word was included in the standard because manufacturers allow the motors to run above their rated powers at low speed, otherwise you wouldn't be able to get the rated power at normal running speed.The Police didn't measure the continuous power, and I can't see any way continuous power could be measured.

In summary, my interpretation of EN15194 is that as long as the manufacturer rates the motor at 250w or less, then the vehicle is legal regardless of how much power the motor actually outputs.

From my experience, you'll struggle to find any EN15194 certified ebike on the road, where you wouldn't be able to measure at least 500W from the battery. Most are in the range 540W to 760W. That includes the systems from Bosch, Shimano, Yamaha, Brose, etc."
 

thelarkbox

Esteemed Pedelecer
Aug 23, 2023
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Really? I saw a posting on Endless Sphere not that long ago .... From a Dutch subscriber.
Ok the Dutch have yet to vote in an orange rapist famous for never paying his bills into power or to divorce from europe, but they are not immune to the sunday spurt reporting standards of today, look at the reporting of Israeli footy fans in Amsterdam..
 

Fatgadget

Pedelecer
Aug 22, 2011
29
3
Ok the Dutch have yet to vote in an orange rapist famous for never paying his bills into power or to divorce from europe, but they are not immune to the sunday spurt reporting standards of today, look at the reporting of Israeli footy fans in Amsterdam..
Going down a rabbit hole I have zero appetite to join you...Sorry.and Bye.
 
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Ocsid

Esteemed Pedelecer
Aug 2, 2017
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Hampshire
The second key word is "continuous", which is different to peak power. The police measured peak power. That word was included in the standard because manufacturers allow the motors to run above their rated powers at low speed, otherwise you wouldn't be able to get the rated power at normal running speed.The Police didn't measure the continuous power, and I can't see any way continuous power could be measured.
I agree, the use of the term "continuous" makes any legal action on power a complete gift for a defence barrister. Probably the intention from the moment it was penned?
 

Fatgadget

Pedelecer
Aug 22, 2011
29
3
Perhaps it is measuring cutoff speed rather than power...
What I do know for a fact is Met Police check power out with a watt meter...Under what sort of criteria I have no idea. Anything over and above 250W they seize and confiscate. Make your choice and take your chances I suppose
 

Ocsid

Esteemed Pedelecer
Aug 2, 2017
453
271
81
Hampshire
What I do know for a fact is Met Police check power out with a watt meter...Under what sort of criteria I have no idea. Anything over and above 250W they seize and confiscate. Make your choice and take your chances I suppose
I would suspect they seize every ebike they put on their dynamometer, working on that basis.
They would see peak power, and have no way of knowing what the maker has determined as "continuous" power, other than read the label, which can be done without any test kit.
 
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thelarkbox

Esteemed Pedelecer
Aug 23, 2023
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oxon
What I do know for a fact is Met Police check power out with a watt meter...Under what sort of criteria I have no idea. Anything over and above 250W they seize and confiscate. Make your choice and take your chances I suppose
When they take a bike compliant with en19154 yell in here for backup if a cut n paste of @saneagles post above fails to save the bike. farage is still a wannabe regarding the putin/murdoch/trump/musk conglomerate so no police state just yet even drugs need to be proven to be drugs before prosecution/destruction atm.
 
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Fatgadget

Pedelecer
Aug 22, 2011
29
3
When they take a bike compliant with en19154 yell in here for backup if a cut n paste of @saneagles post above fails to save the bike. farage is still a wannabe regarding the putin/murdoch/trump/musk conglomerate so no police state just yet even drugs need to be proven to be drugs before prosecution/destruction atm.
Jeez! Are you for real??
 

Fatgadget

Pedelecer
Aug 22, 2011
29
3
As Seneagle said there is no legal direct power restriction. Why would police check power?
Are you not aware that 250W is the max top limit for e-bikes in the jurisdiction in the UK?...And the EU as well??
 

soundwave

Esteemed Pedelecer
May 23, 2015
16,967
6,526
my bosch ebike has a 1000w motor under the 15mph limit a motor can use as much power as it can, 25ow isn't going up any hill.

tho my controller is limited to 20 amps but with the speed limit removed i can hit near 40mph on the flat :p
 

matthewslack

Esteemed Pedelecer
Nov 26, 2021
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EN15194, not EN19154.
 
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Ocsid

Esteemed Pedelecer
Aug 2, 2017
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Are you not aware that 250W is the max top limit for e-bikes in the jurisdiction in the UK?...And the EU as well??
Time to read LINK, where it clearly states "maximum continuous rated power of the electric motor must not exceed 250 Watts."
Wholly different thing to "maximum power", "top power".

"Maximum continuous rated power " is what a motor maker arbitrarily deems is a rating it can deliver a power of, "continuously", and they also decide what they deem "continuous" as, which might be way different to what "joe public" might assume. That could be continuous for say 30 minutes, or 30 hours, that choice is whoever's "rates" the motor.
 
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sjpt

Esteemed Pedelecer
Jun 8, 2018
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Winchester
Are you not aware that 250W is the max top limit for e-bikes in the jurisdiction in the UK?...And the EU as well??
Yes, the limit for rated continuous power is 250w. Most motors that meet 250w rated continuous are happy with max of 500w at least, many a lot more. You may say that is silly; yes it is, but it's the law.
 
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