Brushless motors + ESC help!


I am very new to the field of robotics and I want to upgrade an existing project. The old motors were the following.
Which ran on a Sabertooth dual 25A motor driver.

I want to really upgrade this system with some nice beefy motors like FlipSky BLDC, or turnigy 6374 motors. Ideally I want to spend around $300 on the ESC and motor combo, and it would be nice to find a dual motor system if possible for tank steering, but it is not a deal breaker to just use one motor.

I am struggling on two things here.
(1) How can I compare high quality motors which display the useful wattage value for power, to my existing motors (2 in series) which only provide (Torque Constant of 1.2 oz-in/amp, Voltage Constant 1125 RPM/volt, and Stall Amperage of 155 amps)? I really want to find motors that are something like 50-100% more powerful
(2) I am new to BLDC ESCs and I have been trying to learn more about VESC vs ODRIVE and I am not sure which is a better option, or if I should consider cheaper ESCs.

I would really appreciate any advice on creating such a drive system! thank you!
More info:
Things I don’t care about are acceleration tuning, noise, and probably a lot of other stuff I don’t know to mention
Things I do care about are the ability to slow down or break, going really fast consistently, being able to control speed with PWM from both receiver and Arduino.

Thanks to anyone in advance

  1. Drill motors are surprisingly powerful for their price. It sounds, based on what you said, you want twice the torque. Power = Current x Voltage. When you say “they provide useful wattage value for power”, the question is which “power” are the indicating? Is it maximum continuous power, power at stall, or at maximum efficiency?

  2. VESC:

There seem to be a lot of articles online comparing VESC and ODRIVE. Normally if the controller can provide the current at the voltage, and you don’t seem to care too much about optimization, you should be ok.

Just opinions - we’ll see what additional insight others might provide.

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Thanks for the response!

After much reading up online I have found out that fundamentally it is best to compare DC motors by comparing their torque Vs Rpm graphs! At least for my purposes.

And further more I have learned that Vesc is good for high-speed control and acceleration/deceleration control. Odrive is really good at torque control and precision operation due to its design to work with encoders.

Just in case it might help someone else, these are some of the sources that really helped me. The key is to find stall torque, and no load speed.

Once you have them (y-intercept and x-intercept respectively) you have the Torque vs RPM graph. The next step is understand that the torque is derived from the torque constant which lets you correlate torque to current. Finally, once you know how much current your driver can supply, you know where you stand on the curve! And for further understanding, each torque vs RPM curve is unique to each voltage applied. So upping the voltage will increase both terms.

…unless your controller has a current limiting feature, then the torque curve wil be cutoff at low RPM.
Also interesting are efficiency vs. RPM curves to find the sweet spot of a motor.

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