Electric Roadster

Show off your E-Scooter or Motorcycle creation here.
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Dui, ni shuo de dui   10 kW

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Re: Electric Roadster

Post by Dui, ni shuo de dui » Apr 13 2021 6:53am

Thanks!
First reason was that I wanted more power, I love the sabvoton but the most powerful version is still limited to only 260Amps battery, I wished for more.
Also, the 260A version has a crappy form factor, I don't really like it, I prefer the old brick ones.

Last but not least, I got a good deal on this controller as a second hand unit from a good friend, so it wouldn't have been reasonable to pass on this opportunity. :wink:
:bolt: New Build in Progress: Electric Roadster, 30 000W Kelly KLS72701, 24S2P A123 cells :bolt:
viewtopic.php?f=12&t=109246

:bolt: My electric Ninja 250 clone: 16 000W Sabvoton 72200, 23S2P A123 cells : :bolt:
viewtopic.php?f=12&t=90032

:bolt: My electric Scooter: 11 000W Sabvoton 72150, 72V 50Ah LiFePO4 cells: :bolt:
viewtopic.php?f=12&t=75912

fatty   10 kW

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Re: Electric Roadster

Post by fatty » Apr 13 2021 12:02pm

Thanks!
Best of luck on this build. Most impressive.

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Dui, ni shuo de dui   10 kW

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Re: Electric Roadster

Post by Dui, ni shuo de dui » May 07 2021 8:58pm

Not much major udates, I'm working on the little stuff.

Essentially tidying up everything and testing the bike. I've made about 300km with it so far and it works okay, but I have some issues with setting up the controller properly. There are two problems, which I guess come from the same cause but I can't quite find it:
-The motor will vibrate and make a terrifying noise at some specific rpms
-If I run both of my bikes at the same stabilized speed, the red one will consume twice the power the black one does. It is super inefficient.

Other than that, the bike runs well already, it makes pretty good power and it outperforms my other motorbike in acceleration. But I'm sure it will deliver even more once properly tuned.
I'd really appreciate some help here, I'm kinda struggling with the stupid Kelly interface and I don't know what I did wrong.

I'll post some screenshots of my settings for the experts to help, but meanwhile here is a video of the issue:

:bolt: New Build in Progress: Electric Roadster, 30 000W Kelly KLS72701, 24S2P A123 cells :bolt:
viewtopic.php?f=12&t=109246

:bolt: My electric Ninja 250 clone: 16 000W Sabvoton 72200, 23S2P A123 cells : :bolt:
viewtopic.php?f=12&t=90032

:bolt: My electric Scooter: 11 000W Sabvoton 72150, 72V 50Ah LiFePO4 cells: :bolt:
viewtopic.php?f=12&t=75912

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JimVonBaden   100 W

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Re: Electric Roadster

Post by JimVonBaden » May 08 2021 8:59am

Dui, ni shuo de dui wrote:
May 07 2021 8:58pm
Not much major udates, I'm working on the little stuff.

Essentially tidying up everything and testing the bike. I've made about 300km with it so far and it works okay, but I have some issues with setting up the controller properly. There are two problems, which I guess come from the same cause but I can't quite find it:
-The motor will vibrate and make a terrifying noise at some specific rpms
-If I run both of my bikes at the same stabilized speed, the red one will consume twice the power the black one does. It is super inefficient.

Other than that, the bike runs well already, it makes pretty good power and it outperforms my other motorbike in acceleration. But I'm sure it will deliver even more once properly tuned.
I'd really appreciate some help here, I'm kinda struggling with the stupid Kelly interface and I don't know what I did wrong.

I'll post some screenshots of my settings for the experts to help, but meanwhile here is a video of the issue:

Mine made similar, though not quite so loud, noises until I got the controller set right. Look at my final settings on this thread: viewtopic.php?f=2&t=111363&p=1653869#p1653869 Cleared up all noises, and made it substantially quicker off the line and overall. I have not yet done a distance test, but I suspect that economy will also significantly improve.

wookiepedia   1 µW

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Re: Electric Roadster

Post by wookiepedia » May 30 2021 3:07pm

I have to comment on your thread, this is an incredible clean build and I'm very impressed at your craftsmanship. I'll be watching future updates.

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Dui, ni shuo de dui   10 kW

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Re: Electric Roadster

Post by Dui, ni shuo de dui » Jun 08 2021 4:22am

Well... some bad news and some good news, but mostly bad ones

I crashed the bike pretty hard. I was accelerating at full throttle, and for some reason I'm not yet totally clear of, the bike gave me the famous wobble of death. At that time, I was over 100kph, and the wobble was so violent that it actually ripped off the direction stop.
So I fell on the floor pretty violently and slipped for what seemed to be a very long time. The bike did the same and came to a stop around 80-100 meters later, while I stopped maybe 20-30 meters before. Got lots of scratches everywhere, my helmet hit the floor and got destroyed, clothes ruined, etc.

Anyway, I was very, very lucky since I had nothing broken, only scratches and bruises. Went to the hospital the next day just to pass an X ray to make sure my hip wasn't broken: all good!

Now for some good news: while the bike sustained some damage, it is actually incredibly minimal given how bad this could have been. The only annoying part is the scratch on the paint, I'll have to repaint it once again, but it's relatively small damage. I'm very surprized about how tough the 3D printed side covers are, the bike grinded the floor for about a hundred meters but the cover is still in once piece, without any crack! Insane.

The right handlebar broke off, since it's carbon fiber it can't really bend. But it took me 15 minutes to make a new one so that's really no biggie.
The direction stop is gone, I'll have to make a new one.

Aside from these, there seems to be no other damage to the bike. I've already repaired most of it and tested at low speed and everything seems fine.
It was two weeks ago, I've now almost entirely recovered from the crash so it's all good. I'll try to be more careful now and also check the bike again to make sure there is no mechanical issue with the fork.

Some pics of the damage, it really doesn't look like it was such a big accident looking at the bike, but it was:
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:bolt: New Build in Progress: Electric Roadster, 30 000W Kelly KLS72701, 24S2P A123 cells :bolt:
viewtopic.php?f=12&t=109246

:bolt: My electric Ninja 250 clone: 16 000W Sabvoton 72200, 23S2P A123 cells : :bolt:
viewtopic.php?f=12&t=90032

:bolt: My electric Scooter: 11 000W Sabvoton 72150, 72V 50Ah LiFePO4 cells: :bolt:
viewtopic.php?f=12&t=75912

SlowCo   1 MW

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Re: Electric Roadster

Post by SlowCo » Jun 08 2021 5:04am

:shock:

Glad you didn't break anything and are almost fully recovered :thumb:
Maybe mount a steering damper to prevent a future speed wobble?

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Chambers   100 W

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Re: Electric Roadster

Post by Chambers » Jun 08 2021 5:20am

+1 on the steering damper - Glad you're OK

Elektrosherpa   100 W

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Re: Electric Roadster

Post by Elektrosherpa » Jun 08 2021 5:26am

Congratulations for the mild effects of this accident !
Glad to hear that nothing serious happened to you.

When looking at the damage pics, it really looks like not much happened-except the ripped off steering angle limiter...
Seems your build is really solid.
(and your body, too... :mrgreen: )

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fechter   100 GW

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Re: Electric Roadster

Post by fechter » Jun 08 2021 8:39am

Did you figure out why it went into a wobble? I've had bikes that did that at high speed. A steering damper can help, but shouldn't really be needed if everything is built right. I've heard that a loose front wheel bearing or loose swing arm bearing can cause this. Steering head angle also makes a big difference.
"One test is worth a thousand opinions"

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JimVonBaden   100 W

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Re: Electric Roadster

Post by JimVonBaden » Jun 08 2021 9:30am

SlowCo wrote:
Jun 08 2021 5:04am
:shock:

Glad you didn't break anything and are almost fully recovered :thumb:
Maybe mount a steering damper to prevent a future speed wobble?
Same here. Tough bike and rider.

My first thought was a steering damper. Your rake is a bit steep, so this will definitely help.

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stan.distortion   100 W

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Re: Electric Roadster

Post by stan.distortion » Jun 08 2021 10:11am

Hadn't come across this build before, stunning work! Shame to hear about your spill though, not nice at all :(
Frame design is notoriously difficult, manufacturers didn't get in consistently right until the 1990s and still make screwups today.

It's amazing watching road racing here in Ireland, superbikes on poor quality public backroads quickly shows what works and what doesn't. Classics are particularly interesting, as fast as some of the modern classes but where the stiff modern designs are putting up a fight, the better of the classic frames are soaking up the irregularities.

Personally I'd start with a clean slate after a spill like that, probably go for a perimeter or even simple spine with the packs re-shaped around it but my feeling is it's stemming from the single downtube. Bringing the twin bottom tubes up to the headstock might make a big difference and could be tried out by adding to the existing frame (ie. three downtubes temporarily to test). Some torsional tests could reveal a lot, putting side and linear loads on the front wheel and measuring deflection.
Projects indirectly sponsored by https://www.dash.org/

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neptronix   100 GW

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Re: Electric Roadster

Post by neptronix » Jun 08 2021 10:37am

Looking at your frame design versus common motorcycle designs.. i cannot identify any causes for this wobble off the top of my head. Perhaps the angle of a wheel is slightly off.. headset bearings would be the most likely place to find this misalignment of course.

Glad you survived the fall at such high speed without broken bones. Praise physics and the creator of your choosing. :thumb:
"Love and compassion are necessities, not luxuries. Without them, humanity cannot survive." - Dalai Lama

My first major build: 1.6kW 8T MAC motor on a Trek 4500 MTB.
Monster MTB: Leafmotor 1500w @ 4kW on a Turner O2 full suspension.
The monster scooter: Heavy duty Cannondale semi recumbent - under construction.
Blue Dream: Maxaraya FS semi recumbent and high efficiency mid-drive - under construction.

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Chalo   100 GW

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Re: Electric Roadster

Post by Chalo » Jun 08 2021 11:06am

neptronix wrote:
Jun 08 2021 10:37am
Looking at your frame design versus common motorcycle designs.. i cannot identify any causes for this wobble off the top of my head.
If I had to guess, I would bet on torsional flexibility between the headstock and swingarm pivot. Many motorcycles using frames of this layout have the motor as a stressed member. Those that don't, still have motor mounts that can constrain torsional movement beyond some point.

Contributing factors to wobble that I have seen are excessive steering trail and worn front tires.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

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neptronix   100 GW

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Re: Electric Roadster

Post by neptronix » Jun 08 2021 11:40am

Very good point.. i cannot really tell from the pictures of the battery but it does not seem like the battery is providing that support in the middle of the frame.
"Love and compassion are necessities, not luxuries. Without them, humanity cannot survive." - Dalai Lama

My first major build: 1.6kW 8T MAC motor on a Trek 4500 MTB.
Monster MTB: Leafmotor 1500w @ 4kW on a Turner O2 full suspension.
The monster scooter: Heavy duty Cannondale semi recumbent - under construction.
Blue Dream: Maxaraya FS semi recumbent and high efficiency mid-drive - under construction.

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Dui, ni shuo de dui   10 kW

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Re: Electric Roadster

Post by Dui, ni shuo de dui » Jun 08 2021 11:38pm

Thanks everyone, your nice comments made my day!

I'm not sure yet what caused the wobble, it could be something wrong with the bike itself, but I was also ticking most of the wrong boxes while driving this day:
-full acceleration
-small pothole
-very, very heavy bag (about 20kilos). To add a little bit to the drama, the bag contained several relatively high power lithium batteries, they took a serious hit too... :roll: So yeah, first thing I did after getting up was to throw the bag away, in case the batteries inside would catch fire :lol:
Total recipe for disaster as you can see.

My bike is very lightweight, so my own weight (90 kilos) + the 20kilos of the bag was almost equal to the bike dry weight (113kg). I'm not sure wether that was part of causing the wobble, but it really didn't help to recover from it and avoid crashing.

I'm fairly confident that the frame geometry and stiffness probably isn't the cause, because it is exactly the same frame as for my black motorbike and I didn't have wobbling issue driving it everyday for four years. Rake is the same, geometry is the same, only the rear swingarm system is a little bit different, the red bike is using some rocker arms. The only difference between both frames is that I cut off the rear on the red one, but that should have no impact on twisting the front, or very minimal.
But it's just my opinion and I'm no frame expert so I still keep this possibility opened.

I will check my wheel alignement, bearings and make sure everything is properly tightened though.
Also, I don't know much about suspension tuning, so it is plausible that I didn't set my fork correctly after putting is back together. I'll need to educate myself on that matter so if anyone had a good youtube video to recommend on that I'm all ears!
:bolt: New Build in Progress: Electric Roadster, 30 000W Kelly KLS72701, 24S2P A123 cells :bolt:
viewtopic.php?f=12&t=109246

:bolt: My electric Ninja 250 clone: 16 000W Sabvoton 72200, 23S2P A123 cells : :bolt:
viewtopic.php?f=12&t=90032

:bolt: My electric Scooter: 11 000W Sabvoton 72150, 72V 50Ah LiFePO4 cells: :bolt:
viewtopic.php?f=12&t=75912

Elektrosherpa   100 W

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Re: Electric Roadster

Post by Elektrosherpa » Jun 09 2021 3:13am

Dui, ni shuo de dui wrote:
Jun 08 2021 11:38pm
The only difference between both frames is that I cut off the rear on the red one, but that should have no impact on twisting the front, or very minimal.
Well... if this really is the ONLY difference, it COULD be the reason.
Do not underestimate that you (in this case 90+20kg) sit on this part, and you are not as stable as steel tubes - I mean: a body is also kind of "wobbly", with all the meat, and joints which can move...
Maybe you can post a picture of both rear ends in comparison, so that we can have a look at the differences?

bitDad   100 mW

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Re: Electric Roadster

Post by bitDad » Jun 11 2021 12:20am

awesome build :bigthumb: :bigthumb: :bigthumb:

Barncat   100 W

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Re: Electric Roadster

Post by Barncat » Jun 21 2021 7:09pm

Dui- you were very lucky to have escaped serious injury with that crash. A death wobble is not normal and indicates a design problem or faulty assembly. I primarily suspect those thin plates that the swingarm attaches to that are not triangulated to anything- coupled with that very heavy hub motor rear wheel... I'd also gusset the joint between your downtube and the dual tubes under the battery.

Then methodically go front to back over every bearing and fastener, especially the head tube, and also check for lateral slop in your wheels/axles.

The geometry of your build would exacerbate any "perfect storm" of bad road condition events, with the steep seat angle, clip on bars and high pegs, and no gas tank to grab with your thighs to stay connected. Any head tube angle steeper than 73* isn't very forgiving. Also, if your front tire happens to be a bit smaller actual diameter than your rear tire you can get head shake.

Clean build though. Hope you get that sorted...

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