Running Spark Max and Talons at 18v

Hi everyone. I am working on my Senior Project for University (WPI) and we want to use the Talons and the Spark Maxs however we wanted to run our robot at 18v instead of the standard 12v. I looked at the docs and saw that the nominal voltage was 12v, but there was also a min and a max of 6v and 28v for the talons and 5.5v and 24v for the Sparks. I was wondering if anyone had tried running talons and/or Sparks at 18v successfully. Any help would be appreciated.

I believe the answer is yes, it will work, for the Talon SRX. Haven’t used them myself, but I have heard of others using them at up to 24v with a voltage compatible motor.

The SparkMAX I am unsure of, but I have seen some people express concerns over the voltage rating for the NEO motor. The SparkMax can likely handle the voltage just fine given that it is rated for it, but the motor you are pushing with it (likely a NEO) may not handle it in an expected manner.

Both NEO and MAX will be fine at 18v.

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To back this up, I recently tested NEOs (albeit under no load) with an 8S LiFe pack (26.4V nominal, 29.6V peak) and they survived no problem.

REV had told me 28V max, so I wouldn’t suggest the above necessarily… but the 28V seems safe!

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This is good info. I’d be curious how that setup performs under load.

There are two failure modes… Overcurrent and overvoltage.

I’d expect the SPARK current loop to protect the controller, but it’s not a bad idea to design the system such that it isn’t capable of stalling at full duty cycle output.

Overvoltage is based on voltage rating of components so it should be fine. You could see higher transients when the motors are regenerating onto the DC bus though.

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Out of curiosity, what is the maximum frequency that the SparkMAX will create?

@AdamHeard does the Neo spin faster when the Sparkmax is being given 24 to it’s input, or no because a Neo is essentially being driven by the frequency of phasing it’s windings? Does the Spark Max output a higher frequency when being given a greater input voltage?

Good question.

I drove open loop over PWM and the motor seemed to go appreciably faster on the bench. This is hardly a real test though.

I’d wager you’ll get 2X the RPM at 24V, but with build coming up I likely won’t touch this project until summer now.

Good info. @dyanoshak any further details on how this works when giving a Spark Max higher input voltage? I too am interested in running via PWM with 24V to the input.

Thinking on this more, the fact that the NEO 550 has the same number of pole pairs with more than twice the free speed of the regular NEO at 12V means the controller has plenty of frequency margin to run a regular NEO at 24V.