# Running sensored motor without sensor wire



## nutz4rc

The title speaks for itself. Has anyone tried this and did it work. I know that you lose the benefit of the sensor detecting temp, rotation, etc; but I have a unique situation and just thought I would ask.


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## nutz4rc

Apparently no one has tried this or knows. Hmmmmm maybe I will just go for it and see what happens.


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## ta_man

nutz4rc said:


> Apparently no one has tried this or knows. Hmmmmm maybe I will just go for it and see what happens.


I've done it.

I ran a Novak 5800 (8.5T) motor on a XXX-T (off-road stadium truck) with a Castle Sidewinder (sensorless) ESC. It was an old SS with the non-removable sensor harness, so I wrapped the sensor wire around the shock tower. :lol:

I actually thought the motor ran better (smoother/easier to control) with the Sidewinder ESC than with the Novak sensored ESC I had used it with in a different truck.

The thing is, this is only going to work well if the motor has a high enough KV or enough poles, or a low enough roll-out that it is easy for the ESC to to start the motor.

In other words, a 21.5 in a pan car or a 25.5 in a VTA probably won't give you good results with a sensorless controller. Yet a 1700KV four pole motor in an electric 1/8th scale (same KV as the 21.5) will work fine with a sensorless controller. I'm even using a 1580 KV motor (same KV as a 25.5) in a 1/8th scale with a sensorless controller (Mamba Monster) and have no starting or running issues.

The 1/8th scale setups have more volts, more poles, and more slop in the drivetrain (compared to a pan car or VTA) and so it is easy for the controller to start the motor. The rollout of my 1580KV motor in my 1/8th scale is only 1.5" (4S LiPo setup) compared to, what? 4.0" in a pan car.


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## nutz4rc

I should have just sent you a PM and saved the trouble posting. You seem to be a fountain of info based on other posts you have made. This will be a 13.5 in a 1/10 dirt oval Custom Works car. It may be fine. Thanks for the info.


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## ta_man

Thanks. :lol:

It might work well enough so long as it is not a direct drive. With direct drive you might have cogging issues on startup though the slack in the CVDs might be enough to get you going. Your success also might depend on your track size(!). Bigger track -> higher rollout -> harder to start. Small track -> lower rollout - easier to start. Also, I'd expect better results in a 2S car than a 1S car.

My club runs MudBoss with 13.5s on a 360 ft run line oval. I would not expect sensorless to work there, especally with the weight of a slash, but I just might try it with the sensor cable unplugged to see what happens once. (Can't run it that way in the races because it is supposed to be blinky mode.)


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## nutz4rc

Thanks again. I am going to try it as this is a lighter 1/10 car with a full tranny; it may work ok.


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