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The main aim is to connect 4 motors in parallel each with separate ESC's to a single GND. I want to do this because there is a limited number of GND sockets built in the Arduino microcontroller. I have made a simple schematics that is hopefully a functioning parallel connections of the ESC, motors and batteries. Would this theme work for its purpose?A schematics showing 2 motors each with ESC's connected in parallel

There is one wire directly from one of the ESC's to the GND socket in the Arduino. Then below that another the GND wire from the next ESC joins with the main wire down to the GND socket on the Arduino board. Please note that the +5v wires from the ESC's are left disconnected to anything. Obviously, the signal wire to the digital I/O on the Arduino board are separate for each set of motor and ESC. The three wires from the brushless motors are connected to the ESC's as per normal.

Would this work? Or are the wiring from the motor to the ESC dysfunctional?

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  • \$\begingroup\$ connecting two GND wires together should be OK, But your two power supply's wiring looks a bit questionable. \$\endgroup\$ – Icy Jan 18 '16 at 14:19
  • \$\begingroup\$ @Icy thanks for the comment, Icy. Yes the power supplies may be dodgy for its purpose, but I'll find a way round that:D \$\endgroup\$ – user97484 Jan 18 '16 at 14:49
  • \$\begingroup\$ What I mean is that according to your diagram one of the ESC's is powered by one battery, the other is powered by the difference in voltage between the two batteries - I don't think this is what you intended. \$\endgroup\$ – Icy Jan 18 '16 at 14:53
  • \$\begingroup\$ @Icy Indeed so. I'm trying to power each motor with different power supplies, as a single battery will not suffice driving all 4 motors. I have 4 batteries in total. Is connecting the batteries in series the only way round to this? But I did not do so because the voltage will be too unnecessarily high. \$\endgroup\$ – user97484 Jan 18 '16 at 14:57
  • \$\begingroup\$ You can use separate PSU's for each ESC - if they require single end PSU (as opposed to split/dual rail you would normally have one end of the PSU connected to the common GND, and the positive side to each individual supply input. If they require split rails, you would have the common point of the PSU's connected to GND and individual positive / negative terminals connected to individual ESC's - in this scenario you would need 4 pairs of 'battery' style PSU's. You would not connect the PSU's in series. Update your question with details of the ESC's you are using, and that should help. \$\endgroup\$ – Icy Jan 18 '16 at 15:07
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In your diagram the power supplies are wired in series 'back-to-back' so the top ESC is only getting the difference between their voltages. Most ESCs have their signal ground connected to battery negative internally. If the signal grounds are connected together and there is a significant voltage difference between them (eg. because the power supplies are in series), a large current could flow which may burn out the wires and/or destroy the Arduino.

Each power supply should be wired to each ESC separately. The ground wires of each ESC signal lead must go to Arduino ground. Powering each ESC from a separate PSU ensures that motor current won't try to go through the signal leads.

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If you want to power two ESCs from the same PSU then make sure that the negative battery wires are firmly connected to the PSU with short thick wires. If the negative battery lead of an ESC becomes disconnected then it will draw power through the signal ground wire from the other ESC (not good if your motors are drawing high current!).

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