Hey! I've built a dirtbike using Votol em200 2sp + qs138 90h motor. Finally, after almost a year I've finished the conversion. I'm running the default

M

MarcoPalacios99

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Hey! I've built a dirtbike using Votol em200 2sp + qs138 90h motor. Finally, after almost a year I've finished the conversion. I'm running the default configuration on the controller, but it seems very slow compared to the specifications (13,5kw and 80nm peak power). I've not fiddled with anything, but does anyone have experience tweaking Busbar current, flux weakening, rate of rise, or any other parameter than can affect performance?

Here you can see a video riding, It's in Spanish haha:

I've tried changing flux weakening but the motor seemed to "slip" and make some weird noises so I reverted back to stock.

You can connect with me using any of these networks: @m.palacios99 | Twitter, Instagram, TikTok | Linktree, happy to help if I can.
 
Hey! I've built a dirtbike using Votol em200 2sp + qs138 90h motor. Finally, after almost a year I've finished the conversion. I'm running the default configuration on the controller, but it seems very slow compared to the specifications (13,5kw and 80nm peak power). I've not fiddled with anything, but does anyone have experience tweaking Busbar current, flux weakening, rate of rise, or any other parameter than can affect performance?

Here you can see a video of riding, It's in Spanish haha:

I've tried changing flux weakening but the motor seemed to "slip" and make some weird noises so I reverted back to stock.

You can connect with me using any of these networks: @m.palacios99 | Twitter, Instagram, TikTok | Linktree, happy to help if I can.
 

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I don't have much experience tweaking but I can say that many motors do not live up to what the manufacturers/vendors claim. The same is true of battery packs and controllers. These things can be over hyped. The same with car tires and many other products. Is the motor bike extra heavy?
 
What kind of battery do you use?
 
Do you have a battery/bms capable of feeding the motor/controller enough amps? Also what speed setting do you have the controller in? Might help to post pics of your controller settings. Also worth contacting e&c and doing a session to go through your controller settings. They helped me with my qs120 em100 combo and it made a world of difference in power.
www.electroandcompany.com

Electro & Co. Inc.

Electric Motocross Powertrain Kits
www.electroandcompany.com www.electroandcompany.com
 
endless-sphere.com

Votol EM-100 & EM-150 controllers

Is power actually shutting off to the system, or is the controller simply ceasing to respond to control inputs? The former indicates the BMS is shutting off it's output; the latter indicates the controller is hitting some form of LVC (there are often multiple levels of this in programmable...
endless-sphere.com endless-sphere.com

Here is the biggest votol thread, go through your settings
 
Hey! Yes, good idea, I`ll describe my system.

I have a Qs138 90H motor joined to a votol em 200 2sp controller, with a full Kit I purchased that has screen and accelerator. Battery is a custom 72V 20S10P battery with samsung cells that can peak 250Amps of discharge.

I´ve attatched 3 pics of the 3 configuration pages I have on my controller, if anyone can share their experience tuning this controller to push more mover, it will be appreciated, thanks.
 

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My experiance is from the older model em150, so things might be different. But it seems like you have real grandmother settings.. Page one, busbar current should set your battery current when you are not in sport, if you think your battery can handle 250A I would set that. You can also play a little with the phase current, I think you can get maybe 100A more. But that puts more load on the mosfets.
Then rate of rise sets the throttle responce, I think 250 is max. I would guess your settings are rather sluggish.
Rate of decline is how fast it releases, if you have regen on throttle release you might want to keep it low. But otherwise I would go high, like 250.
Page 2
Sport mode limiting current, should set your battery current in sport mode. So I would go for 250A as you are battery limited. HDC, I would either turn it off or rase the speed limit. But be aware that high rpm might damage your controller if it looses sync with the motor.
I would turn off soft start..
Make one change at a time and test. Make sure to save before making changes so you can load the old settings if something goes wrong.
Make sure to enable sport, it made a lot of difference on the em150 at least..
 
Awesome, tried everything you said and I can really feel the torque now. Might try to go to a 70t rear sprocket (if I find it) to have extra torque, since now I'm running a 13t to 48t and I don't really need the top speed
 
Okay, I will try the bigger rear sprocket. I've been looking at the torque graphs and the problem is that I get max torque at 175rpm, and with current gear that happens to be 15kmh, and that's why it feels slow when I accelerate from 0.

With the new gear, max torque will kick in at around 4kmh, so hopefully that solves the issue.
 
IM wondering about your 10p batterie pack vs 250a load.
Is it 21700 cells 5ah at 5C or 18650 at 2.5ah trying to run at 10c ?
Because temporary peak current is 1 thing but if you look at voltage curve at 10C rate, you will see how fast the voltage is dropping. The system won't have full performance if voltage at controller terminal drop too much...

I have a similar setup to build with same controller and i'm planing a 60-80ah pack to stay below peak current to reduce voltage drop, reduce temperature rise and extand cycle life.

I'm also using the V3 motor with 2,37 primary reduction on a 18 inch wheel. It really help to size the secondary chain sprokets closer to normal gas dirtbike options. Without the primary one, if you have similar wheel size, you would need a rear sproket the size of the wheel for a dirt bike. I would reduce the front one as much as you can without compromising chain minimum radius.

I calculated mine based on wheel speed for about 90kmh max at motor max rpm. 90 is more than enough for me on dirt trails... Theorically i calculated i would have rear wheel torque availaible between a crf150 and a crf250 shifted in second gear at peak motor torque.
Not sure yet how it will react since with the gas one you start in first gear but you also drop the clutch at an rpm well below peak torque....
Assuming the torque curve from Qs is tested with less amps than the the voltol can output, it should give a little more than calculated. I expect to get a good feeling this way...

Having a 2 speed lightweight gearbox option would be very nice, one could plan more gear reduction in first to get more rear wheel torque and being able to reach more speed in second gear. This would bring an ebike with this size of motor to compete against larger gas dirtbike.
 
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