Hi All,
I’m looking for a direct drive brushless motor to power a RC Car of about the size seen in the image below. It should be able to have a high rpm so gimbal motors (I think) are out of the question. Do you have any suggestions? Also, would people recommend the B-G431B-ESC1 or a VESC? Quite new to FOC, so any information is most welcome!
What speed are you wanting this car to go? 6 or 60mph? I reckon you might get 8 mph out of gimbals, assuming no gears.
Might be worth starting with motor/gear selection, and work back from there. My guess is that vesc is overkill and also 4x more expensive than esc1.
Might be interesting to hear what are your reasons for not using off the shelf rc control systems - this might help inform what you’re direction is.
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Thanks for the quick reply!
Ok, good to know that gimbal motors might be sufficient, so here are more concrete requirements:
- We are looking for a direct drive setup, so no gears
- The motor should have good torque, for powerful acceleration
- the max speed we are looking for is 18 revolutions/second or 113 radians/second
We aren’t using off the shelf RC components, because they don’t fit to our use case and requirements (autonomous driving robot for a competition, direct drive, powerful acceleration).
You’re right, ideally this motor can be driven (with heat sink and fan) by the B-G431B-ESC1 as the VESC is too expensive.
EDIT: Forgot to mention: it will be powered by a 2 Cell Lipo (7.4 Volts)
This should be achievable with gimbal type motors, I think.
A thread of interest to you might be: https://community.simplefoc.com/t/challenges-going-faster-than-certain-rpm/1688
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A single motor with high torque on a 4-wheeler…sounds like a drift car to me?
Do you want to drive both rear wheels with it at least? No differential, but good traction.
If you want to use two in-wheel motors, I recommend the MKS dualFOC plus It’s even cheaper than ESC1 (with free shipping) and has two BLDC drivers.
I’ll be using two direct drive motors in the back. Thanks a lot for the recommendation!
If this car weighs less than 2kg and isn’t pulling anything then i doubt you’ll need a heat sink on esc1. I used an esc1 to drive a skateboard without heatsink for short bursts.
(I did a YouTube video on it about 3 years ago)
I reckon the standard simplefoc shield would be enough to drive most 10ohm+ gimbals up to about 5cm radius e.g iflight 2804 to about iflight 5208 gimbal motor but the esc1 might give more torque head room.
Similarly the simplefoc mini board (which is just the power stage with no mcu) paired with arduino uno r4 or esp32 is another option.
Esc1 is tiny and fiddly. Just soldering on the motor leads is a challenge (use lots of flux!). Sensor options are also limited.
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Ok good to know, thanks! I’ll give the esc-1 a try.
I think the ESC1 has a specified minimum voltage higher than 7.6V.
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Grizzly makes a very good point. Many of these drivers have a min voltage. esc1 says 3s to 6s. So 2s is under voltage. From memory I think they do spin motors at 8v but a fully charged 2s is only 8.4v - so might go under and switch off before quarter of the battery juice runs out.
Some of the storm32 boards e.g. STorM32-BGC v1.3 (which can drive 2 or 3 gimbal motors) from memory go down to lower voltages than most (?7v?) but can be difficult to find.
Using less than 3s carries risks.
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Same for the MKS Dual FOC: 12V-24V. 
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