Serious Setup Question

[Alfa Spirit]

Hi,

I have a Serious setup question, what seup should you choose and why ?

With a serial setup (high voltage) the current in the circuit is lower, HV esc' s are necessary.

[akula]

Hello my friend

This is a question for your Smash Shark building or another project ??
It depends of the size of your boat...

[Mike W]

B. I just converted a boat from setup A to setup B and the power difference is night and day even carrying double the MA weight. And its not the additional current capacity - I was well within the C rating of the packs before and they barely got warm.

[E36racer]

I think the biggest influencing factor is the decrease in the amp draw when going from 22.2v to 44.4v. It makes it easier for the 750kv motors to reach and hold high rpm than the 1500kv motors on the lower voltage. It’s just more efficient at higher voltages because it is easier to push less amps through all of the wires and circuits. The parallel 6s packs in A have twice the c-rating amp output capability and double mah capacity when compared to the same packs used in B, but run time probably isn’t much different between the two options.

Interesting experiment for sure [emoji106]

Disclaimer- I’m not an electrical engineer that specializes in AC motor design.


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[Thunder29]

I would power the ESC's separately regardless of if you are doing series or parallel setups.

[RaceMechaniX]

The benefit of going with a 12S1P set-up is halving the current the ESC's need to push. This may reduce the cost of the ESC's assuming you have not purchased them. It could also have the opposite effect depending on the power level, where high current 6S ESC's may be cheaper.
Depending on how hard you are pushing this set-up the HV approach will be more efficient, but only slightly.

If i were choosing it would come down to reliable ESC's in both ranges. There are several good 6S ESC's and several good HV ESC's.

[Alfa Spirit]

I would power the ESC's separately regardless of if you are doing series or parallel setups.

Rx battery? 2S LiFe in both setup, 6,6 Volts.

[Doby]

Looking forward to actually seeing a finished product someday.

[Alfa Spirit]

With 12S voltage batteries and ESC' s should be warmer, less power lost with this setup

[larryrose11]

Tyler Garrard ( RaceMechaniX) is spot on. I would argue that the efficiency effect is significant, but this is semantics.
In general, power loss (and heat generation) is:

Power loss = (current)*(current) * Resistance.

To go from a 1500 KV motor to a 750 Kv motor, the resistance should double, but the current is halved. Because loss is a function of the current^2, the total loss goes down in HV setup.
There can also be other efficiency effects, like the motor winding reaching field saturation at high current, but you can't say that part for sure without specific knowledge of the motor.

Disclaimer: I AM an electrical engineer who works with large AC motors (50-500 kW)