Can you software limit a bafang motor to 250w to make it road legal?

[Woosh]

Haven`t been following this anti-dumping thing but isn`t this specific only to countries within the EU, ie not UK after 29th March - or is it worldwide?

it's going to be effective in the entire European Union's Customs Union, that includes also Turkey, the Channel Islands, IOM, Gilbraltar.
I don't know about Norway and Switzerland.
It could well be that you can buy Chinese e-bikes cheaper in Switzerland, the country that the EU Commission uses to compare e-bikes price against Chinese bikes. Talking about chalk and cheese but it's how the EU Commission worked out that Chinese bikes are underpriced.

 

[flecc]

Haven`t been following this anti-dumping thing but isn`t this specific only to countries within the EU, ie not UK after 29th March - or is it worldwide?

It is an EU importing measure, but of course we are facing at least a couple of years transition from next year when the rules still apply. So we'll be affected in the home market for a long time too if buying Chinese.

Also some of our companies sell in the EU. Wisper for example, so origin still means anti dumping duty gets added.

And if we compromise with something like EEA membership, could be permanently here as well.
.

 

[cyclebuddy]

So is everyone dodging the answer to my question because you don't know or don't want to tell me?

I don't know anyone who has tried to de-rate a 750 watt drive to make it behave like a cheaper 250 watt one (so I don't know if it can be done).

Why do you want to pay a premium for a heavy-duty drive with associated controller just to then de-rate it to make it less powerful and street legal? It doesn't make any sense to me.

 

[seosamh1977]

Because I want to use it for proper mountain biking, ie taking it to peaks, that's why I want to oomph, to cycle up things I normally wouldn't cycle up. But I also want to play around with the power settings, to see what different powered bikes feel like. I'd probably not run it around much beyond assist 1-3 on the streets tbh(I've had a loan of a bbshd for a week, so I know how it feels).

I basically just want to mess about with the settings and test out what other less powerful bikes would feel like.without having to buy/hire them.

 

[peter.c]

I am sorry if I miss interpreted the traffic officer and the way he explained it to me, I suspect they will not look to hard unless you are doing something stupid or are involved in a crash then they will take a hard look.
Off road buttons or over speed buttons or programmes are not legal for road use and the regs are vague about how long you can exceed the 250 watts limit for

 

[anotherkiwi]

He was wrong, that isn't true, 48 volts is perfectly legal and there are entirely legal models with that voltage.

But if one puts a 48 volt battery onto a 36 volt bike or kit, that makes it go a third faster and so it becomes illegal. That's probably what he has misinterpreted.
.

48v maximum, there are not a lot of those batteries on the market, they all charge up to 54.6v...

Because I want to use it for proper mountain biking, ie taking it to peaks, that's why I want to oomph, to cycle up things I normally wouldn't cycle up. But I also want to play around with the power settings, to see what different powered bikes feel like. I'd probably not run it around much beyond assist 1-3 on the streets tbh(I've had a loan of a bbshd for a week, so I know how it feels).

I basically just want to mess about with the settings and test out what other less powerful bikes would feel like.without having to buy/hire them.

Revolutionary idea use the assistance level button! It gives you the different Amps. Example of a vanilla KT 15 Amp controller and a GSM mid-drive (BBS01 clone):

5 - 720 W battery hot off the charger (48v - 12S LiPo)
4 - 360 W
3 - 180 W
2 - 90 W
1 - 45 W
0 - 0 W

Some versions of the KT controller apparently give different percentages.

 

[flecc]

48v maximum, there are not a lot of those batteries on the market, they all charge up to 54.6v...

That's a common misunderstanding, just like that of the police officer. It's the nominal voltage that applies in law, so a nominal 48 volt battery is permissible. They are on the EU market after all and have been for some while.

It's the same as the power position, nominal 250 watts legal regardless of how much actual continuous power is available.
.

 

[anotherkiwi]

It hasn't been tested in court yet, even d8veh was intrigued by the wording (my red text):


1 Scope

This European Standard is intended to cover electrically power assisted cycles of a type which have a maximum continuous rated power of 0,25 kW, of which the output is progressively reduced and finally cut off as the vehicle reaches a speed of 25 km/h, or sooner, if the cyclist stops pedalling.

This European Standard specifies safety requirements and test methods for the assessment of the design and assembly of electrically power assisted bicycles and sub-assemblies for systems using battery voltage up to 48 VDC or integrated a battery charger with a 230 V input.

This European Standard specifies requirements and test methods for engine power management systems, electrical circuits including the charging system for the assessment of the design and assembly of electrically power assisted cycles and sub-assemblies for systems having a voltage up to and including 48 VDC or integrated a battery charger with a 230 V input.

 

[flecc]

It hasn't been tested in court yet, even d8veh was intrigued by the wording (my red text):


1 Scope

This European Standard is intended to cover electrically power assisted cycles of a type which have a maximum continuous rated power of 0,25 kW, of which the output is progressively reduced and finally cut off as the vehicle reaches a speed of 25 km/h, or sooner, if the cyclist stops pedalling.

This European Standard specifies safety requirements and test methods for the assessment of the design and assembly of electrically power assisted bicycles and sub-assemblies for systems using battery voltage up to 48 VDC or integrated a battery charger with a 230 V input.

This European Standard specifies requirements and test methods for engine power management systems, electrical circuits including the charging system for the assessment of the design and assembly of electrically power assisted cycles and sub-assemblies for systems having a voltage up to and including 48 VDC or integrated a battery charger with a 230 V input.

That same wording "up to and including" is used in the law for 250 watts maximum.

So this again is not relevant, "up to" applies to the manufacturer's stated voltage, just as the maximum permitted 250 watts applies to the stated power only. That is how the EN151954 standard operates and how the EU standards for pedelecs have always operated. The EU companies own pedelec production demonstrates this, since their 250 watt bikes all give far more continuous power and their 48 volt bikes charge to well above 48 volts.
.

 

[seosamh1977]

48v maximum, there are not a lot of those batteries on the market, they all charge up to 54.6v...



Revolutionary idea use the assistance level button! It gives you the different Amps. Example of a vanilla KT 15 Amp controller and a GSM mid-drive (BBS01 clone):

5 - 720 W battery hot off the charger (48v - 12S LiPo)
4 - 360 W
3 - 180 W
2 - 90 W
1 - 45 W
0 - 0 W

Some versions of the KT controller apparently give different percentages.

Ahh, interesting. So basically my orginal guess is true? Limiting the amps effectively limits the power?

So if I limit the amps in a 48 v 750w system to 11.25amp, that effectively makes it a 250w bike? (which is just what the assist does, incrementally, essentially?)

 

[anotherkiwi]

My point is the words "rated power" aren't used as they are for motor output. This puts voltage on a different legal footing.

Motor power is a consumer protection thing - the motor must provide up to 250 W continuous, that it may also provide over is out of the scope of EN15194.

EDIT: I made a big boo-boo the European Directive 2014/35/EU is for voltage between 75v and 1500v DC. This post has been edited.

A 62v nominative (17S ?) battery is thus outside the LVD.

 

[anotherkiwi]

So basically my orginal guess is true? Limiting the amps effectively limits the power?

So if I limit the amps in a 48 v 750w system to 11.25amp, that effectively makes it a 250w bike? (which is just what the assist does, incrementally, essentially?)

No that means you are running your motor at 540 W. The bike Wattage is the Wattage engraved on the motor whatever you do to limit output. 250 W output is 5.2 A x 48v.

 

[seosamh1977]

aye but that's peak power. so how do you figure out equivalent continuous power? peak is obviously easy to figure out, the continuous one seems like a bit of a mystery tbh. Can that only be measured in a lab?

 

[anotherkiwi]

aye but that's peak power. so how do you figure out equivalent continuous power? peak is obviously easy to figure out, the continuous one seems like a bit of a mystery tbh. Can that only be measured in a lab?

Continuous power is a customer guarantee and the motor has been tested (in theory) by the manufacturer to comply to the number stamped on the motor. So yes you are correct, only in lab conditions as set out in EN 15194.

You should be able to run your 750 W Bafang for 2 hours at full Amps without it getting warm at 750 W (15 Amps plus or minus a smidgen x 48v). You can try it out on a bike track if you like, you will need a 1.5 kWh battery of course (750 W x 2 hours).

 

[flecc]

My point is the words "rated power" aren't used as they are for motor output. This puts voltage on a different legal footing.

Motor power is a consumer protection thing - the motor must provide up to 250 W continuous, that it may also provide over is out of the scope of EN15194.

The Voltage is a safety thing "Because of limiting the voltage to 48 VDC, there is no requirement with regard to protection against electrical hazards." And the EU regulations apply from 50v > so a 48v nominative battery fully charged falls under the scope of those regulations (https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/640829/nlf-electrical-equipment-regulations-2016-guidance.pdf)

Nonetheless, no 48 volt e-biker will ever be successfully prosecuted, the authorities clearly happy with the situation as it stands with the stated voltage accepted.

Catching someone will be difficult with half the running time under 48 volts.

And the 250 watt power limit is also on safety grounds, anything over that requiring registration, insurance and an option for rider licencing etc.
.

 

[anotherkiwi]

I corrected my big mistake (mixing AC with DC - ouch!) in previous post, sorry flecc, 62v nominative is outside the Low Voltage Directive which is probably why you can find those on the market. They charge to 71.4v peak which should in theory give a top speed of about 60 km/h (loaded) with a 36v hub motor.

 

[mike killay]

This business with throttles intrigues me.
Kit bikes can have them?
Throttles are not illegal at all, simply that assistance must cease when the rider stops pedalling. In practice this of course means that a throttle is not needed but as far as I can see 'Ghost' pedalling (i.e. turning the pedals without putting any pressure on them) whilst using the throttle is legal as long as the motor stops as soon as you stop pedalling.

 

[peter.c]

Hi
The cop was not a problem he was just showed general interest in my e bike and I had no worries as it was legal that's why I have two bikes one road and one for trails I suspect he was a lycra road bike weekend warrior

 

[flecc]

This business with throttles intrigues me.
Kit bikes can have them?

Sort of in the UK. When the latest amended regulations were introduced which banned throttles, the DfT announced that they'd introduce a type approval class for throttle equipped pedelecs from January 1st 2018. I knew at the time they couldn't legally do that and said as much, and sure enough it hasn't happened.

However, classifying it as being for type approval permission meant it only applied to manufactured e-bikes, so by derivation it didn't apply to kits which are used in home builds. That's been interpreted as kits being ok with throttles by many.

I actually don't agree and believe any e-bike with a full acting throttle is a low powered motorcycle which should be registered. The EAPC regulations are quite clear on this and I'm sure the courts would also be.
.

 

[flecc]

Hi
The cop was not a problem he was just showed general interest in my e bike and I had no worries as it was legal that's why I have two bikes one road and one for trails I suspect he was a lycra road bike weekend warrior

It's in forces where e-bikes have been adopted or tried that the traffic officers often know the law on pedelecs. Both Essex and the City of London police forces have trialled them.

Amusingly most forces trialled the usual 250 watt bikes or even bought them in the years before 6th April 2015 when the old limit of 200 watts was in force and 250 watts very much against the law. Worth remembering if one ever tries to prosecute unnecessarily!
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