How to get full power from a dead stop using Sabvoton 96120 controller

ZebVB

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May 10, 2022
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I have read in other posts how they can pop wheelies with the same set up as I have. 273 8000watt V2 motor with the 96120 driving it. My question is how do I get it to have full power from a dead stop? It seems to limit how fast you can take off until you are going about 15 mph. Then it speeds up much faster all the way up to full speed. This controller is unlocked. I would like to have full power from a dead stop so I can pull out into fast traffic without getting hit. Please help!
 
I think the controller is way under-powered (300 phase amps peak?) in amps for a QS 273 8000W. You need somewhere between 400 and 800 phase current (depending on motor kV) to really get all the torque out of the motor (if your battery pack and BMS can handle that). See QS Motors own info:

QS 273 8kW.jpg

But also the programming of your Sabvoton controller could probably be tweaked to deliver more instant throttle response and start up amps. Search for Sabvoton programming.

And people do wheelies on pushbikes so it's all about technique :wink:
 
ZebVB said:
I would like to have full power from a dead stop so I can pull out into fast traffic without getting hit. Please help!
You probably want to stop just short of wheelies since flipping over backwards when pulling out into traffic is probably the worst case scenario. Also, if you increase the throttle ramping until you're doing wheelies from a start, you'll also increase the chances of unexpected wheelies at speed, and that gets pretty scary.
 
Thanks for all the input from everyone. lol I guess I should clear up my intent. Im NOT looking to do wheelies...lol Im just trying to make the bike take off faster from a dead stop... Right now I have the controller unlocked and have brought the phase current up to 450. My bike is a 2012 Ninja 250 I converted to electric. With the current settings I can reach 80mph. Which is fast enough for me. I just want more torque at take off. No matter how much throttle I give it .. it wants to take off at what seems like a pre selected pace. I dont get full torque until about 15 mph.. then she takes off. I want that power from a dead stop... thanks again for all the input.
 
I have heard the Sabvoton handles the takeoff current differently? IDK I will try to find the reference. I think I might have read something like that. 80 mph is still pretty fast.

IDKY you cant do them off the line, my Kelly thingies ( controllers) have alot of " umpf" and I can power wheelie easy at starting speeds with 100A. I have had a 8.5kV motor and a 13kV motor @ 72V nom. Both would easy. Maybe its weight or geometry related.
 
I have the same issue with my scooter. 21S with a SVMC72150 but it is not unlocked, because the unlocking software did not work

Which KV does your motor have?
Max. Volts?
Are you using weakening field to get to 80mph?

I get 103kph/62mph with my motor.
With weakening field I get 110kph. From 35kph upwards the controller draws 14kw from the battery.

I measured phase current at 0RPM, it takes a little time to reach full phase current, but it gives full phase current.
I thought it starts with reduced current, as it feels like more tourque at around 20mph/30kph. But the first two seconds after a stop feel to slow.
That is why I change to a controller with 850A phase current.
Screenshot_20220423-152653.jpg
 
ZebVB said:
Thanks for all the input from everyone. lol I guess I should clear up my intent. Im NOT looking to do wheelies...lol Im just trying to make the bike take off faster from a dead stop... Right now I have the controller unlocked and have brought the phase current up to 450. My bike is a 2012 Ninja 250 I converted to electric. With the current settings I can reach 80mph. Which is fast enough for me. I just want more torque at take off. No matter how much throttle I give it .. it wants to take off at what seems like a pre selected pace. I dont get full torque until about 15 mph.. then she takes off. I want that power from a dead stop... thanks again for all the input.

Did you ever figure anything out? I've got the SVMC72150 with a 12000w and mine also limits torque up to a certain speed. It's super annoying. I've gone through the mobile app and the mqcon app from my laptop and while some of the changes seemed to help, that limiting is still there. I know it's likely a safety feature, but I'm sure it's also not healthy for a hub motor to receive that much power from a dead stop. Even still, I would like the option to disable that.
 
Degreeless_Engineering said:
I'm sure it's also not healthy for a hub motor to receive that much power from a dead stop.
If the motor and it's torque-transfer mechanism to the frame are properly designed and made for the torque level required, then there's nothing unhealthy (for the motor) about putting the designed level of power thru it at any point.

But...most hubmotors are not well designed for their torque transfer mechanism, using just the tiny axle flats to do this, and most of hte axles are not well made of sufficiently strong materials either, making it even worse...the motor itself doesn't usually fail, but rather the axle itself, usually at the point where the flats end at the shoulder--shearing off rotationally is the most common failure mode.

If the axle itself is well made and so is it's attachment to the motor core supports, and the rest of the motor is also well-made, then the next typical failure point is the dropouts or other torque transfer mechanism, such that the axle spins within them, tearing them up and sometimes damaging the axle, but more often just ripping up the wiring as it tangles around the now-spinning axle...and the damaged wiring often shorts internally between phases and sometimes to halls or other signals, and taht usually destroys the controller, and sometimes other parts on the electrical system.
 
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