Brainstorming ways to make instant 25 km speed limit / low power mode, in case I get inspected.

[marka-ee]

I live in an area that requires e-bikes to have some pretty severe restrictions. They don't like throttles and they only allow power supplementing up to 25 km per hour. On my other bikes, I don't have a problem with this because they look like normal bikes and I just do a lot of ghost pedaling and nobody seems to care. However, now I acquired an old Velomobile which I'm putting in a rear hub motor with a KT controller and LCD3 for the display. I'm going to use a thumb throttle on the right tank control lever. ( They call this tank steering in Velomobiles.) .So I need a system that if it looks like I'm getting pulled over because they like to look at my velomobile because they're so rare, that I have some kind of system in place so I can dumb it down to make it essentially instantly fully legal. Disconnecting the thumb throttle is pretty easy, either with a magnetic reed switch or just pulling the connector or doing something else so that I can say it's completely disabled. That's no problem. But with the PAS, I'm wondering how I could set it so that it could only power up to 25 kilometers per hour without affecting the usual usage I have which allows power above that speed.
One option would be to have a small microcontroller monitoring the speed and simply back off any PAS signals or other signals so that it no longer goes after that speed.
A more complicated option is to have a microcontroller send over the UART serial signal to the controller commands to instantly reprogram it to a max speed and max power setting, which would satisfy the requirements. But that's a lot harder because then I'd have to research the UART protocols, etc., etc. There is a German site where they did write some software that does some of this, but it doesn't look very well organized.

Anyhow, I'm open to suggestions that might be simpler than these complicated things that I've been dreaming up.

 

[neptronix]

20 inch wheels have a higher power density per lb than larger wheels. Does your velomobile have small wheels? because you could use a very high turn count, legal motor, at a higher amperage than stock and see some 33% power gain by doing so.

I'd combine this with torque sensing for legality and of course an appropriate chain drive ratio so that you can actually pedal and combine human and motor power.

A mid drive might actually be a good choice. You can say it goes faster due to aerodynamics.. which is true.. no fault of your legal kit goes faster on a streamlined bike.

Dunno if that's legal in court though, lol

 

[marka-ee]

It's a leiba x-stream, two 20" on front, 26" on back. I really like direct drive. I have that on my also 26 inch two wheel recumbent. It works out well because there are very few hills near me and I like the silence and lack of fiddly bits to wear out inside. Also, I prefer not to drive that long chain with anything as it makes too much racket.

 

[neptronix]

I like DDs too.

I believe you can get a grin all axle with 250w lasered on it.
Don't know if that helps your case at all

 

[neptronix]

If you were to have a fast winding motor and relied on amps to make your speed.
Your cop switch is an amps limit.

Some controllers with old style shunts would help.. have a switch that removes/bypasses one of the shunts for 2x the amps!

 

[E-HP]

You want something similar to this, but for ebike RPMs, using a wheel magnet sensor for input and a small output relay to cutoff the PAS signal.

Summit Racing SUM-830453 Summit Racing™ RPM-Activated Switches with Digital Readout | Summit Racing

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I'm wondering if these can the modded or if there are lower speed applications where these types of circuits are used?

 

[Az.]

People shouldn't really drive uninsured vehicles without plates at illegal speed.

 

[docw009]

Just curious. They expect the motor to hold 15.5 mph and not have a throttle in something like this?

 

[marka-ee]

Yes, that's what my velomobile looks like.I don't have the wheel covers, however. The law is a little ridiculous because with these and pedaling alone, you can get to 50 or 60 km per hour because of the streamline nature of the vehicle. But I still have to suffer a possible inspection, and you know how they are about technicalities. Most of the time I would not be using this with what they call the race hood, which is the part with the motorcycle windscreen. That whole part comes off.That way it attracts less attention because it doesn't look so much like a cruise missile.

Az: As it's completely legal for me to do 50 or 60 km per hour(Attainable with no motor whatsoever.), I don't need plates for that. It's perfectly legal. The motor is basically just for hills,or accelerating up with traffic.

 

[stancecoke]

There is a German site where they did write some software that does some of this, but it doesn't look very well organized.

you can flash the open source firmware to your Kunteng controller, it has a feature to switch off the limit by a Morse code with the brake lever. Or by a secret gesture on the screen of your smartphone with the BluOSEC app.

But the Kuntengs are outdated and the OSEC firmware is not maintained any more.

regards
stancecoke

 

[fechter]

It wouldn't be too hard to make an Arduino that looks at the speed sensor signal and pulls down the throttle or disables the PAS signal whenever the speed exceeds a preset value. There may be a way to do this with a CycleAnalyst also.

 

[stancecoke]

It wouldn't be too hard to make an Arduino

As @marka-ee already recognized, there are many similar projects in the German forum. But as far as I understand, he doesn't want to tinker around

I've build something similar based on an ATTiny, written in BASCOM, but it's much smarter to implement that feature in the controller's firmware directly. There is no need to use additional hardware at all

regards
stancecoke

 

[E-HP]

Still thinking of andapting off the shelf stuff. The other automotive application for an rpm activated switch is for shift lights. Those are a lot cheaper than the rpm activated cutoffs. Since this one only goes down to 1000 rpm, you could use a wheel speed sensor, but with 4 magnets. That would be 250 rpm. 25kph is around 260 rpm on a 20” wheel, so 250 rpm would cut PAS/assistance just short of 25kph.
The light circuit could be used to trigger the relay.

https://a.co/d/2QEuSfE

 

[Az.]

Az: As it's completely legal for me to do 50 or 60 km per hour(Attainable with no motor whatsoever.), I don't need plates for that. It's perfectly legal. The motor is basically just for hills,or accelerating up with traffic.

but you don't ride unpowered vehicle, do you? That is why you ask people for advice here. My point is people should not encourage others to break the law and give them advice how to get away with it (it especially applies to moderators).

 

[marka-ee]

As @marka-ee already recognized, there are many similar projects in the German forum. But as far as I understand, he doesn't want to tinker around

I've build something similar based on an ATTiny, written in BASCOM, but it's much smarter to implement that feature in the controller's firmware directly. There is no need to use additional hardware at all

regards
stancecoke

I don't know, I may have to tinker around. I have some extra 'Promini' Arduino processors laying around, and those are easy to work with. Where were you getting your tachometer signal from? From a wheel magnet sensor? Or something else? I once took the signal off of a Hall sensor from my motor as a tachometer signal, but that was a big mistake. The voltage regulator in my homemade bike computer failed and fed high voltage back to that hall sensor, frying it and making me non-motorized for a bit !

I'm just building this Velo mobile right now, but I had experience with a recumbent trike already. I found that any speed that you think is fast on a regular bike seems twice as fast when you're very low to the ground. On my trike, my butt is about 6 inches off the ground actually. So I don't want to go all that fast in my Velomobile either, but I don't want to pedal as much as some other people sometimes either.

 

[stancecoke]

Where were you getting your tachometer signal from? From a wheel magnet sensor?

Yes, with a simple Reed sensor from a cheap Speedo, see the schematic:

You have to debounce the signal properly, by hardware and/or by software.