Type of motor controller for RC Car

Using Arduino Motors, Mechanics, Power and CNC
#1

Hi,

I am trying to build an arduino RC car but am not sure if I could use a H bridge motor controller or if i should look for alternatives (e.g. ESC?).

I will be using the an Saturn HPI 20T 540 DC motor.

And will be using a 7.4V Li-lon 1200mah battery to power it

Can is use a standard H Bridge controller (with 2A max current) for this set up? I got a bit worried because it seems that the ESC’s that are sold on RC Car websites seem to be able to handle much higher currents (>10A).

Many thanks,
Toon

#2

That motor can easily draw over 30A if pushed hard. I'd go for a brushed ESC. If you need reverse it might not be very easy to find one. Even those sold as car ESCs don't all have reverse so check the specification carefully.

What are you doing for the gearing? That motor is way too fast to be used direct drive. And a 1200mAh battery won't run it for very long.

Steve

#3

Thanks Steve, I think I may be getting ahead of myself with this project.

Indeed it seems difficult to find a decent ESC for a brushed motor. Any tips on what to go for would be helpful? It seems it can get complicated to ‘arm’ the ESC etc.

Other solutions to control this type of motor also welcome.

I have borrowed some lego technics from my sun to build the car frame and was planning to use some technics cogs to bring it down some gears. Though I am starting to think this motor will be too powerful for this.

I also have a smaller motor (Tamiya type 380, sport tuned) available that i probably more appropriate, but still too powerful. But I am keen to get some speed out of this project.

Noted on the battery.

#4

The Hobby King website has a good selection of ESCs

But first you need to identify the motor you are going to use and the voltage and current that it needs. If you are building the car with Lego I doubt if it is intended for high-performance racing.

What about using a regular Lego motor?

You may wish to consider a continuous rotation servo which has the electronics and the gearing all in a neat package.

...R

#5

Cheers Robin, I agree i should probably start with a simple lego motor and H Bridge. But was quite keen to get some good speed.

I underestimated how much current an RC car motor can draw and how much more complex it makes the project.

Thanks for the hobby king tip, I will check it out and investigate a continuous rotation servo.

#6