nostroke

Ha. Personally, I'm waiting for a class for Nostrokes......

No but I would really like to ride one. There is some personal history for me involved. Somewhere back in ~2003, my fledgling electric motorcycle company, ElectricMoto, was going to build bikes (The Blade) in France, at the Scorpa facility in Ailes. That whole idea never really panned out for several reasons but part of the deal was that I was to show the guys at Scorpa some of the electric propulsion basics. So I hooked them up with motor batteries and controllers from our Blades that we made there and one of their R&D guys packaged one into their trials chassis during the three weeks that I was there in France. It was pretty cool. Fast forward about 10 years, Phillipe Arresten (SP?), who was CEO of Scorpa at the time, starts EM, making electric trials bikes! And it looks really nice. So yeah, I want to ride one big time!

Well, as usual, we can agree to disagree on several of these points. So much of this is subjective and we, silly humans that we are, tend to think that whatever we have done successfully is the way to go. The bottom line is that both GWHY and myself have built electric trials bikes that we really like. Building your own stuff, while daunting to most people, is extremely rewarding. I hate brushless motors, he loves 'em. I say tomAto, you say tomAHto....... I still ride mine almost daily. Its a source of both pain and inspiration. BTW, GWHY, where did you find the hall throttle? I have a friend with a electric bike rental track in the UK and he goes thru both brands of throttle pots like crazy...would love a non-contact hall device but never saw anything commercially available.

The short list, as it were, is this: 1) Use a pancake style permanent magnet motor such as those made by Agni (the best), or Perm 120 (now Heinzman?), Briggs and Stratton E-Tek, or similar. I use brush motors because brushes never actually wear out and the controllers are cheaper (golf car stuff, such as Alltrax 400 amp, 60 VDC max (48 nominal). Also Sevcon, Curtis and others with similar power. You NEED 400 amps or it will be anemic. 2) You should try to direct drive from motor to rear sprocket if possible to get proper gearing, which depends on the motor's voltage constant (kV). Other wise, you may need a stage of reduction gearing, which means a belt or gearset. Both are heavy and prone to reliability issues if not done properly. 3) You have to come up with your own battery and BMS and charger. No simple task but do-able on the Interwebs. The pack should be able to discharge at least 400 amps for brief glorious periods of say 5 seconds. In other words, this is an intermittent, not continuous requirement. Same with the motor, in terms of thermal issues. If this bothers you, you will need a water cooled motor and fan cooled batteries, but I don't see a need for either in this application. 4) Magura and Domino both make twist grips for this application and they both kinda suck IMHO but they work fine most people, a bit twitchy control-wise though, as they are 1/4 turn.. There's more......

I would add that this is all very subjective stuff. I think the jury is still out as to what best provides good control of a trials bike, certainly electric motor based torque response. Personally, I feel that the clutch emulator is an added distraction, but I think most experienced riders would do better with that system, But I don't like it. I have been riding hot rod electric bikes for a long time, probably twenty years (I'm waay crusty). That said, I am pretty sure of one thing...to get a pro level electric bike to leap like a gas bike, controllably, it will need a mechanical clutch. There just isn't enough torque available to simulate a spinning (gas bike ) flywheel launch. And I also think at those high levels, you would need to quickly de-couple ANY motor connected to it, gas or electric, to get the snappy response required on say a double blip. And that's what mechanical clutches do really well. This is not to say that a 'smart' closed loop servo control is out of the question, but I think you would have to take the control inputs largely away from the rider, which is kinda scary, in a autonomous drone / Segway fashion,...and what fun would that be?

I think you may be over-thinking it, biff. Having played with darned near everything you have mentioned, weird cams, logarithmic pots, and microprocessor based programmable ramps...my favorite is a nearly linear crisp predictable (OK, analog!) ramp. On my bike, I expand the pot travel via cable to a linkage that provides about 90 degrees of mechanical rotation, instead of the more typical 45 degrees. On a gas bike, the throttle cable needs to pull exactly the same linear distance as the carb bore (~30mm), so you have to use different twist throttle cams to affect a change in sensitivity. But with a pot (rotary, hall or resistive), you can make the arm or quadrant however you want, relative to the twist grip cam. Wow, now it sounds like I am over thinking it.

It looks like it may be a bit rear heavy from the pix, but I hate being a critic without any beef to back it up. On mine, its about 2% rear heavy, theirs looks like about 8 to 10%, which might be weird. But again, I hate to bash something without anything but a pic to reference.

OK just saw the $9k USD, which sounds more realistic. It really comes down to how many you can build / sell. The more you make the cheaper they get of course. And it looks like they have geared up for some volume. I would love to ride theirs. It sounds like kinda low power but electric specs can be very misleading, ie, continuous vs peak, etc. We Americans always lie on the high side.....they are probably using honest numbers (go figure!) I expect its a torquey bike..... Its hard to make an electric that isn't!

Wow. I don't see how they can do that. IF I take mine to market, which I am still not so sure of doing, it was going to be closer to $10k. I rode mine at Dallesport COTA event this weekend. My first trials event ever so I entered novice at the request of the marshal (yeah, I know, trail riding). But I got to see how the events are structured and had a blast. I did a few intermediate sections and the bike performed really well. Plenty of power for everything in that class, no problem. My wife took a bunch of nice family photos and videos (I let my son ride the first beater prototype), but nothing worth a posting really.

Pretty much the same. This has a more developed battery quick swapping system. Also, 1.2 kWh of capacity. I am using a 500 amp peak controller but in practice it rarely pulls more than 200 amps, even on steep inclines or wheelies. Weighs just 60 kilos (134#). The biggest change really is the chassis, which now has a 4 bar linkage on the rear Olle shock and awesome formula forks and brakes. I'm planing on entering an event this weekend and see how it (and me) holds up.

Just finished a new bike.This is the dash 3 version. New and improved! I got forks and brakes from Formula, wheels from FABA and made pretty much everything else.

Have you looked at the Monty trials rims and tires? I built a few electric bikes for small kids about 10 years ago using them and they are awesome. If you use 24" bicycle rims there are a few wide 3.0" downhill tires like Nokian Gazzalodi. But nothing works as well as a gummy 4.00 x 18 m/c tire, although the scale is a bit out of whack on a smaller rig. Regarding the throttle pot...if you can find a 1" travel slide pot with an audio taper and cable operate it, it has a great feel but its not very durable as most of the pots are crappy (at Radio Shack).

Well, I built up the cable pot system using a 45 degree pot from a Curtis potbox and the Magura 313 Trials Throttle and designed it for 32mm of cable pull, almost a half twist to full throttle. I like it. You have to be more aggressive with it but control is much better. I mounted it on the fork, behind the front number plate, so the cable doesn't have to contend with any steering movement.

I have a funny thing going on with my GasGas conversion..it has a low speed misfire! It acts like a dirty carb or half fouled plug. I am pretty sure its just a dirty potentiometer wiper in the Magura twist throttle, but it adds an element of gas realism that I think is cool, in a twisted sort of way. Its not a distraction because its very minor and just at one distinct throttle position. Anyways, I have had a few people complain of wrist issues using this throttle so I am curious to see if the cable pull pot setup improves things. Because I have no E-Clutch (anti-throttle, whatever), the throttle is crucial to good bike control. The Magura trhottle, with no cable (the pot is internal, in the twist grip assy), its probably too smooth. In other words, there is no friction feedback which I think may actually be a unintended but useful fault in a cable system. That smoothness, combined with a very sensitive quick throttle (about 45 degrees of rotation) can be very fatiguing, requiring too much focus on the throttle.

I am building a new electric trials bike here at my shop and am interested in how that throttle/ anti-throttle clutch setup works for you. On my GasGas conversion here, I am using a Magura twist throttle and its making me sore! Its only a 45 to 60 degree turn and, while it offers great power delivery, its just too hyper. So I have ordered a Magura 120 degree and a Domino 90 degree that I will use to spin a remote mounted pot with a cable. (BTW I have NO clutch / anti throttle set up)

With regard to the clutch, I've all of sudden gotten buried with actual paying work here at my shop and have not had time to do much. But I did come across this accelerometer in my box of old project stuff and have to ask what you think about incorporating a "wheely mode" into this circuit? http://www.meas-spec...nloads/3028.pdf (I can't seem to make the link work in this post.) I recently had to replace the kill switch and found one with a start button, which got me thinking how cool it would be to be able to hold down the start button and have the bike pop up and modulate the throttle at some angle determined by the orientation of the sensor . My thinking is that we could use say the positive or neg mV output to drive a transistor that would control the throttle. I had originally thought maybe a full on 4 quadrant servo would be needed for this, like on the Segway but I'm inclined to think it could work with just a single direction speed control (and careful rear brake use while dialing it in). The one I have here is the 2G version, which seems like what you would need.

I finally clamped a good current meter on my battery lead, pinned it and I saw close to 400 amps ( which is the setting on my Alltrax). I will look around for a higher current shunt. I found yours no problem at Newark. I HAD one lying around..grrr. The one I had was about 1" OD and you would feed your #6 cable thru it instead of the Allegro with solder pins. What do you think? I expect some scaling would be in order most likely (if I can find mine).

You really should have photoshopped the gauges on the dyno. So is that IC a comparator or something of that ilk? The board looks really simple and elegantly analog. If you send the schematic, I will build it no doubt and have it up and running in a few days. One of my issues with twist throttle only control is that it is hell on the right wrist. You have to hold a lot of tension there to maintain control of both the handlebar and the twist grip position, not to mention if you need the front brake. No different than the gas bike really, in that regard. Today I swapped out the stock AJP front master cylinder with a Formula unit off a OEM KTM 80,. with nicer ergo than the AJP, but It has a tiny piston and is nearly impossible to bleed. I think this should help the wrist problem. I hope to have it bled properly in a few years, I'll get back to you then.

Thanks much! I'll warm up the Weller! Ive actually got a few Hall current sensors here but doubt I can find them. We had a fire here about a year ago and I tossed a bunch of electronics stuff that was sooty. And yes, it WAS caused by Lithiums. Store with caution! I think the fire was caused by my own lack of concern to some extent...I had a 24S, 100V 10 AH pack that I knew was leaking and it was in an aluminum sheet metal case. I had forgotten about it for a month or so and one night it decided it had enough. It was not charging or used for several months prior to the ignition, just sitting, leaking and corroding the case. Once bit twice shy. Now I have a flammable storage locker for cells and store bikes where they couldn't ignite anything else IF they went into meltdown mode.

That would be great. I can likely figure it all out. I'm not a EE but I did once make a fuel injection system for a Honda Hawk from a 555 timer set up as a one-shot. (It sucked but did work). I take it this circuit deals with just the throttle control voltage? No other inputs? Hope not because there aint any more inputs! Well, there is a 1/2 speed enabled by B+ but that's it.

So last night I rigged up a clutch pot, using a 5k linear pot with a 12mm stroke, the same as the master cyl piston travel. I think if I put the pot in series with the throttle pot (2-wire), with the low resistance position in the 'clutch out', it would work as normal. But when I pull the clutch in, it will effectively reduce the throttle signal. Due to my dyslexia, I probably have this backwards, so I'll be sure to remove the drive chain while futzing around. It should work similar to your more elaborate scheme, which I cannot do with this controller.

gwhy-To be clear, with your e-clutch, I take it that the twist throttle, when the clutch is depressed, simply sets the peak available power. The clutch lever, as it is released, modulates power within the limits set by the twist grip? The clutch sort of IS the throttle in this case? The more I ride with just a twist grip, I can see a need for a more precise control, which I believe the E clutch would provide, once I got used to it. Another approach might be a non-rotating grip on the right and a index finger trigger on the left side. Seems like this would free up the right hand for better front brake wrangling. I confess, I have as much fun modifying stuff as I do riding. Go figure. Hey how about a foot operated mousetrap suicide clutch!

I guess the next feature we need to see on motor controllers is the ability to play .WAV files. I wonder if I could copyright the pop pop pop of a properly muffled two-stroke?

Damn. Can't wait to see what he gets when he's 5! When I was a kid, I had to borrow our lawn mower motor for my mini bike. Anchored it with plumber's tape. Good to go. So when are you ordering the carbon Marchenisi wheels?

I once took a piezo buzzer and connected it in parallel with two 2 motor leads (brush motor), so it would increase the frequency based on the voltage supplied to the motor. It was very cheap and simple. And annoying! Your 3 phase brushless motors have a lot more levels of control, like speed vs torque, that I'm sure let the engineer tailor things way beyond what I can with my garden variety golf car controller, which acts like a current controller. I would love to try one. Maybe in a few years there will be an electric class in comps, or at least a forum dedicated to full sized electrics. I think I may be suffering from an inferiority complex due to having to post in the kiddie bike forum!