don’t BLDC also have max torque at 0 RPM?
Yes that is correct:
Theoretically, but in reality I have to kick the board to get it going - otherwise it stutters a lot, whereas a brushed motor could give you clean smooth power off the line.
One problem with brushed motors is that the bigger they get the lower the rated RPM, so getting a powerful enough DC that matches RPM range of the BLDC would be tricky.
DougM
Been reading this thread with intrigue, especially as I have a spare motor and ESC laying around. So it sounds like this setup worked quite well considering the weird configuration. I’m happy with the explanation given, but my only question is this:- Would the slower motor create a braking effect as it tries to turn slower?
No it wont slow down. If you use VESC with current control, the motor always try to spin at maximum rpm all the time. If one motor has higher rpm than the other, the drag effect will occur (not braking).
Ideally uneven drive is similar case to car engine differential if I look at it. If there is less load on one side of the wheels, that wheels will spin faster taking all the current and power (normal differential and not slip differential). What it comes to eboard is that the motor and the batteries will self balance the power distribution.
It works exactly the same on a regualr dual drive with the same motors. With two ESCs each driving thier own motor, each one will always try to do its best individually.
I’m not 100% sure how the traction control option in VESC affects this when using dual with the CAN bus. I can’t really tell the difference with it enabled or not enabled honestly.
Here is my plan/theory. Use a Tacon 245kv and SK3 260kv motor with slightly different gearing; 17/36 & 16/36, respectively, since I have both of these motors and could fit them both on one truck. Theoretically, I’m expecting it to run similar to a normal dual drive, but I’m not sure if there would be any issues with running this setup.
Has anyone else tried this type of even uneven setup or have any opinions or comments?
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I don’t see any reasons why this wont work. what ESC’s are you planning on using?
I would be interested in the results… especially with different gearing.
I encourage this kind of thinking. outside of the box, not just what everyone else tells them to do.
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I wonder if you could fit a Tacon 160 and Tacon 110 in a dual rear configuration, then you’d have an uneven drive and disguised as a regular old dr drive. Lol
well the 2 SK3’s that I used in my original setup are so very similar in size that you hardly notice the difference. however you can feel it.
I’m going with torqueboards 6s to start.
This is awesome. Ya’ll know what would be sweet mash up of unique ideas? Carvon skates dual drive from a single motor (pictured) x2 using the Stacked KV motor idea in this thread. Credit to carvon for the drive set up, I just like pictures.
Lol who needs to stop?
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not 100% sure whats the point of this. 
if you run dual motors anyway, will you really ever need the extra torque of one low kv motor? or would you ever need some mixed topspeed of 2 different kv motors when you could just tailor kv to your max desired speed and go with that? I ran dual rear 63mm with max speed 50kph+ and more torque was the very last thing I needed on that setup.
in my eyes, you just add an uneven load that will add extra wear on belts and wheels, will add extra load on motors leading to extra loud bldc noise and you probably loose efficiency too. ontop of that, while accelerating from stand still to max kph, the torque will smoothly swap sides on your truck, so youll constantly have to readjust your weight. probably no biggie, but might add some confusion and possible instability.
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If everyone walked straight in a line no one would dance.
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Not sure this would be the case…the motors are pushing and pulling the board…your weight will alway set you back a little regardless which has more torque … I’m def gonna give it a go just need to figure out the right KV spread between the motors to get a flat-ish Torque curve…well maybe not flat-ish but wider range for torque through the throttle range
Edit: definitely not needed at the speeds you are going but def would be awesome to have that extra punch if needed
What if you used one motor, and had two gears to switch from? One for torque, and then one for top speed once you reach 15mph? The first gear would guarantee a quick startup then the second would lead you to top speed
really? you’re comparing a two motor set-up to a single motor set-up. Of course the dual is going to be faster but not because of the “twin turbo” dual kv motors but because you have two motors! lol!
At low speed, your 400kv motor is adding drag and slowing you down, at high speed your 200kv motor is adding drag and slowing you down. Two of the same motors working together at the same time is optimal.
Mate. A 200kv motor has the same RPM as two 200kv motors.
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Uneven Dual Drive is a very interesting concept.
However I see one big danger for the controller of the lower Kv motor. Why?
Once the lower Kv motor goes past it’s unloaded top speed RPM it generates a voltage that is potentially far higher than that of the battery. That us such is not so bad. But if this voltage is far above of the voltage of the ESC it will damage the ESC. While there might not be a lot of current flowing, the motor will generate voltage spikes.
Let’s say you have a 200Kv and a 400Kv motor and a 6s battery and an ESC rated for 6s. If you have the same gearing for both motors and the gearing is geared at top speed for your 200Kv motor you will blow your ESC.
So your lower Kv motor needs to have an ESC that can handle the voltage the motor produces, in this case 12s.
If you have different gearing for the motors, there is not much advantage.