for this motors   you recommended  2S(7,4)  OR  3S(11,1)  BATTERIES?? SPEED CHANGE MUCH?

Archive OpenRC
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for this motors you recommended 2S(7,4) OR 3S(11,1) BATTERIES??

SPEED CHANGE MUCH?

Regards

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I know this seams simple, but 3S will give you 33% more power and RPM than 2S (not under load). To figure out RPM of the motor, multiple the KV rating of the motor by the voltage of the battery. That then is reduced through the gearing ratios. So the car will go 1/3 faster with the 3S. I run with the 3S mainly because I have a load of them from my airplanes (popular size in the air).

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Ahem, it’s not that simple. P=U²R (or P=U²Z, Z∈ℂ), so a 50% voltage increase will, ideally, result in a 125% increase in power output.
So basically, the 50% increase will increase torque and RPM by 50%.
Generally, 1/10th scale RC cars run 2S lipos, so most ESCs and motors are designed for that voltage.

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Ya, I did considered that. It depends on perspective … If I am traveling at 20mph and then with a increase in voltage I am traveling at 30mph (really the original question) I have increased by 50% but overall I’ve only added 1/3 more speed (due to an RPM increase); as 20/30 is 2/3 and 10/30 (the difference over the overall new speed) is 1/3 more.

The answer to the original question is Yes you will see an increase in speed going from a 2S to a 3S system; assuming your ESC is setup to handle that. Your driveline has to be able to handle the additional torque also.

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This is not to say that the OpenRC car goes 20 and 30mph respectively, I have not clocked mine. (This is only an example for the basic math.)

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@D_Myers
aprox which is the maximum speed of OPEN RC CAR?