Power restriction to 250w UK Limit

[Jonboy]

Hi Guys I'm using at the moment a Lyen 18fet controller with a CA. Is there a simple way (not adjusting the CA) to switch from full power of the controller / CA to 250w on a handle bar switch or maybe something evermore discreet.. I ride very rarely on the main roads so It's not that much of a prob, but be good to get in place to at least cook the local coppers noodle if I get pulled.

Ta

Jon

 

[k1kk0_1t4]

You can select the power mode trought the CA connected to a switch like this:

You need to change the connector of this particular switch or you can buy a similar switch with the plugs compatibles with CA.

You connect it to the CA and program the two different power modes, then you need to program the switch to act not as speed limiter or power limiter but to switch between power modes.

 

[bowlofsalad]

It's important to note that only version 3 of a cycle analyst has this mode switch feature.

 

[d8veh]

There is no 250W limit in the UK. The official limit is 200W; however, we've got a sort of concession to be able to use 250W motors. There's no power limit on the 250w motors, but it must be either marked by the manufacturer as a 250w one or listed in a catalogue or whatever as one. You cannot use a 500w motor (or any other motor labelled or listed higher than 250w) and limit the power. What would you limit it to anyway? The speed must also be limited to 25km/h. Accessible switches to change the speed aren't allowed.

Your bike will therefore be just as illegal whether you have your switch or mot, so not a lot of point in doing it.

 

[zener]

You cannot use a 500w motor (or any other motor labelled or listed higher than 250w) and limit the power. What would you limit it to anyway? The speed must also be limited to 25km/h. Accessible switches to change the speed aren't allowed.

Your bike will therefore be just as illegal whether you have your switch or mot, so not a lot of point in doing it.

I dont belive that. Can you show me the legal text from this?
It would be utterly stupid becouse than would be no regen braking higher than 250w possible. I see regen up to 1kw while riding a hill down safe and slowly.
Any restriction laws that slow us under the lycra power is bogus and easy to cheat. Just use RFID chip in a finger ring to invisible unlock your bike to full lycra power should be implemented in any ebike

 

[d8veh]

Which bit don't you believe?

 

[crea2k]

To be fair 99.9999999% of coppers wont know what wattage the motor is, the law says that you must have a plate on your bike somewhere with the manufacturer, motor wattage etc on it, just get one made up with "250w motor , some random make etc" job done. As long as you dont go thrashing it along at 40mph no one is going to stop you and even if they do if you have a plate stating the wattage etc you can just point them to that, you can get a plate made up on ebay etc for peanuts. I have a 6000w cromotor on my ebike, but the fastest I go on the road is 20mph, as that roughly how fast all the racing bikes etc go, I just make sure my fake pedalling is believable. I only gun it off road or on quiet country lanes, as otherwise its obvious its not 250w.

 

[jesusjesus]

pretty sure the 250w thing is EU-law, so it applies in the UK.

a European .-)

 

[crea2k]

Just have that engraved with whatever you like and slap that on the bike : http://www.ebay.co.uk/itm/Gold-Silver-Metal-Plates-with-FREE-Engraving-/221215546586?pt=UK_SportingGoods_OtherSports&var=&hash=item3381795cda

 

[crea2k]

and get some of these stickers to put on the motor http://endless-sphere.com/forums/viewtopic.php?f=31&t=35048

 

[crea2k]

As the law actually states that you must have a plate on the bike with manufacturer, nominal battery voltage and motor wattage, they arnt going to take it for a test ride to see what it tops out at etc. As long as you have some bogus info on that plate and dont go flying around faster than the other bikes around there isnt a lot they can do. The only way they could disprove the motor power is to get it on a rolling road, or test it. If they ask why its so big, just say its ultra efficient and the size is needed to keep it cool.

 

[d8veh]

pretty sure the 250w thing is EU-law, so it applies in the UK.

a European .-)

The Uk were ordered to implement it, but they didn't, so we still have 200w limit. Nonody takes any notice of it. There's even police forces using 250w bikes..

 

[crea2k]

This is my plate I got made up, il just stick this to the outside of the battery box, job done, it now meets most of the legal requirements lol.

 

[teklektik]

It's important to note that only version 3 of a cycle analyst has this mode switch feature.

Nonsense.
External control of current or speed limiting (3-position switch, pot, etc) has been a standard CA feature since the introduction of the V2 family.

 

[teklektik]

I like the little plate
Similar to 200W motor stickers that Hyena had run off .

There is specific mention of alternate test procedures when the power developed by a motor varies according to the controller, but I've been unable to locate any mention of external switches being disallowed (actually no mention of them at all) or specification plates and required text in the EU regs. This may be a matter of UK law or some case law (?).

I'm trying to understand the situation by law - not be argumentative...
Can someone provide a link or reference to the applicable statutes or regulations about disallowed switches and plates? Thanks.

 

[bowlofsalad]

It's important to note that only version 3 of a cycle analyst has this mode switch feature.

Nonsense.
External control of current or speed limiting (3-position switch, pot, etc) has been a standard CA feature since the introduction of the V2 family.

Wrong, you sure are an ornery one.

I can use a three speed switch with a version 2 CA, but that won't change the amp/watt limit, only the throttle maximum, this is a massive and important difference.

The ability to choose different profiles, that have different watt limits, is what is being suggested and what would fulfill the original inquiry.

 

[teklektik]

Wrong, you sure are an ornery one.

I can use a three speed switch with a version 2 CA, but that won't change the amp/watt limit, only the throttle maximum, this is a massive and important difference.

There is no external CA feature that adjusts the throttle maximum.

The Vi input is specifically designed to limit current or speed. The feature can also be used to implement Current Throttle (as found in the V3).
The OP only wants to limit power by switch - this is a direct application of the familiar CA 3-position switch control of MaxAmps (aka MaxCurrent in the V3).

No one mentioned 'presets' nor is that broad multi-variable control required to externally limit/adjust a single parameter (MaxAmps).

Seriously, please don't tell me this is impossible - the manual details the application and I used the feature on my bike with a V2 before the V3 was released.


In addition, the AuxThreshold parameter available in the V2 makes it possible to have a 2-position switch and adjust the lower current limit entirely via the CA menus without external trimpots. There's a bit of a lower range limit, but it works quite well.

• EDIT: Perhaps the language issue makes it a little unclear what k1kk0_1t4 is saying, and if he is in fact referring to V3 style presets as the solution, and you are referring to presets, then you are correct in pointing out that the V2 does not have that feature. But to the point of the thread and the availability of a V2 solution - you are incorrect - the V2 does have external control of current limiting and will certainly do what the OP requested. This is the relevant use of the switch and what I assume is being discussed.

 

[bowlofsalad]

Wrong, you sure are an ornery one.

I can use a three speed switch with a version 2 CA, but that won't change the amp/watt limit, only the throttle maximum, this is a massive and important difference.

There is no external CA feature that adjusts the throttle maximum.

The Vi input is specifically designed to limit current or speed. The feature can also be used to implement Current Throttle (as found in the V3).
The OP only wants to limit power by switch - this is a direct application of the familiar CA 3-position switch control of MaxAmps (aka MaxCurrent in the V3).

No one mentioned 'presets' nor is that broad multi-variable control required to externally limit/adjust a single parameter (MaxAmps).

Seriously, please don't tell me this is impossible - the manual details the application and I used the feature on my bike with a V2 before the V3 was released.


In addition, the AuxThreshold parameter available in the V2 makes it possible to have a 2-position switch and adjust the lower current limit entirely via the CA menus without external trimpots. There's a bit of a lower range limit, but it works quite well.

Re-read k1kk0_1t4's suggestion. Mode switching is a feature that exists in CAv3, not CAv2. All I was saying was that in order to have mode switching (it's a specific concept) you have to have a CAv3. I will cede you your point, if you can accept that you and I are talking about different ideas and that your discussion wasn't necessary.

 

[teklektik]

We have cross posted - I already added an edit above after re-reading k1kk0_1t4's post.

In the end, the idea is to answer the OP's question and since the thread never actually addressed that and left the impression (IMHO) that the V2 could not address the OP's request, then I think the discussion and material from the V2 manual is on point.

 

[crea2k]

This is what it says on the UK government website :

EAPC requirements
The requirements are:

the bike must have pedals that can be used to propel it
the electric motor shouldn’t be able to propel the bike when it’s travelling more than 15mph
the bike (including its battery but not the rider) must not be heavier than 40 kilograms (kg) if it’s a bicycle, or 60kg if it’s a tandem or tricycle
the motor shouldn’t have a maximum power output of more than 200 watts if it’s a bicycle and 250 watts if it’s a tandem or tricycle
the bike must have a plate showing the manufacturer, the nominal voltage of the battery, and the motor’s power output

https://www.gov.uk/electric-bike-rules

Im not sure what a switch will achieve, as its not like the police are going to test drive your bike to check that your are telling the truth about the top speed.
The first one is pretty simple, as most have pedels, the second point, well just dont go on the road faster than all the other bikes, then they have no reason to stop you, third point, unless they carry a scales around with them I cant see how on earth they can test this at the road side. Fourth, this is also untestable at the road side, and I cant see any police knowing the difference between a 200w motor and a 2000w motor, and last, just get a plate made up with the wattage on, this then pretty much explains away the point about the motor wattage, unless they want to take it away for testing, which they wont.

 

[teklektik]

This is what it says on the UK government website :

https://www.gov.uk/electric-bike-rules

Good link! Thanks. I've looked at the EU regs in detail, but this link is a good pragmatic summary of the UK statutory interpretation.

In the US there are no Federal regs regarding use of bikes - instead we have a potpourri of individual state laws - all different. This business of hidden switches and on/off road modes, etc has been discussed and argued to death. Staying under the radar with good behavior is IMHO always good advice, but beyond that it's a personal decision on how to best address the illegality of your bike... lots of ideas and choices.

Good idea or bad, from a technical perspective it's possible to limit the battery current and indirectly the approximate motor power as the OP queried. The basic idea is to provide at least two different control voltages to the CA that scale the configured MaxAmps to 100% or some lower value. This can be accomplished different ways - here's an example using a V2.3 although the same circuit can be used with earlier models and the Vi input:


With AuxVoltage set to 'Current', this circuit can be arranged to select either 100% or (0-66%) of the configured MaxAmps using AuxThreshold as an adjustment parameter. Here the V2 allows 100% with the switch open and the configured lower percentage when it's closed. We want to pick resistors so that the POT input is a bit less than 2V with the switch closed, so we might use R1=6.8K and R2=3.9K to get a voltage around 1.8V.

The POT input has a 0-3v working range with the base voltage set by AuxThreshold and the relative POT input voltage in that range scales MaxAmps 0-100%. In this approach we slide the POT 3V working range so that the fixed 1.8V point set by the resistors appears to move up and down relative to the lowest voltage of the range defined by AuxThreshold. This makes 1.8V effectively take on different percentage values in the 0-100% range. For example:

• If we set AuxThreshold to 1.8V, then the POT working range is 1.8v-4.8V and the switch will chose between 100% and 0% (lower limit).
• If we set AuxThreshold to 1.5V, the range is 1.5V-4.5V and the switch will chose between 100% and (1.8V-1.5V)/3.0V = 10%.
• If we set AuxThreshold to 0.0V, the range is 0.0V-3.0V and the switch will chose between 100% and (1.8V-0.0V)/3.0V = 60% (upper limit).

Rated motor power is power output not battery power input. Using a working efficiency of 80%, the allowable battery power for a 200W rated motor is about 200W/0.80 = 250W. Figure in the nominal battery voltage and you get the Amp limit for a 200W rated motor (more or less). It's a bit of trial and error, but AuxThreshold can be tweaked in to get pretty close although there may be an adjustment granularity issue if MaxAmps is very very large.

So - that's perhaps the simplest means to accomplish this with the V2 - other approaches might use a 3-position switch and trimpots.

Whether using a limiting switch is legal or even a Good Idea for this purpose is another matter...

Enjoy!

 

[d8veh]

The above links detail the present UK law, but nearly every electric bike sold in the UK is 250W or more. There's police forces using 250w bikes too. As a result of that situation, a deputation from the trade had a meeting with the Department for Transport, who subsequently wrote a letter, which say's basically that nobody would be prosecuted for using a 250w bike. They also said that it was OK to use an independent throttle with a 250w one. It was in that letter that they specifically mentioned speed/power boost switches. I don't know where I heard it, but the rule is that if you have adjustable speed or power above what's allowed on the road, it mustn't be possible to change the setting while riding the bike.

 

[teklektik]

I don't know where I heard it, but the rule is that if you have adjustable speed or power above what's allowed on the road, it mustn't be possible to change the setting while riding the bike.

Thanks! That's very helpful.

I might suggest that this would perhaps allow a key-operated switch out of reach back by the controller that could switch on-road and off-road mode. For many, this might provide a very useful solution and is easily doable with simple V2 limiting or V3 presets. (Of course, circumventions such as a hidden reed switch in parallel with the keyswitch spring to mind for scofflaws, but in any case the basic legal viability of >250W bikes is huge.)

 

[crea2k]

The above links detail the present UK law, but nearly every electric bike sold in the UK is 250W or more. There's police forces using 250w bikes too. As a result of that situation, a deputation from the trade had a meeting with the Department for Transport, who subsequently wrote a letter, which say's basically that nobody would be prosecuted for using a 250w bike. They also said that it was OK to use an independent throttle with a 250w one. It was in that letter that they specifically mentioned speed/power boost switches. I don't know where I heard it, but the rule is that if you have adjustable speed or power above what's allowed on the road, it mustn't be possible to change the setting while riding the bike.

The other strange quirk of the law is that the power they specify is the nominal power of the motor, not the max power, so like my cromotor that will run at 6000w continuous, it can run up to 10kw, or 12kw , cant remember which max in bursts, so your 250w motor could easily burst at 1000watts, then there is the geared motors and motors that run off the rear sprocket where the power at the wheel depends on the gear ratio used.

 

[d8veh]

The other strange quirk of the law is that the power they specify is the nominal power of the motor, not the max power, so like my cromotor that will run at 6000w continuous, it can run up to 10kw, or 12kw , cant remember which max in bursts, so your 250w motor could easily burst at 1000watts, then there is the geared motors and motors that run off the rear sprocket where the power at the wheel depends on the gear ratio used.

That's right. The motor only needs to have 250w written on it (in a convincing way).