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I've been programming and testing an Arduino based quadcopter for the past 4 months. Until now I did not need to use an external power source for my sensors. Now I want to use the 'BEC' power from my electronics speed controllers.

Each of the 4 ESCs gives 5V @ 2A. I would set these up in a parallel circuit, which would give me 5V @ 8A (theoretically).

I also want to use a cheap chinese voltage sensor to sense the voltage from my 5000mAh 25-50c 11.1v battery. I'm not sure if it is safe to connect my batteries wires to my sensor with the 125A that it can put out.

My question is whether or not it is safe to have a common ground on Arduino with an 8A power supply AND if it is safe to use a 5V 8A power supply with these sensors.

Here is a problem that I've encountered before:

while powering my IMU off the BEC and sending motor PWM signals, my sketch would run for about 10 seconds then freeze. It was not until I powered my IMU off the Arduinos 5V power that I was able to run the sketch flawlessly. What could have been causing that?

I've made a diagram of my circuit in Fritzing (not actually tested yet due to fear of ruining my sensors). I'm using an Arduino Mega.

Fritzing diagram

  • I have frequently heard that it is a bad idea to wire multiple BEC's in parallel. My guess is that this is because they will not all output exactly the same voltage. You might want to find out what type of regulator your ESC's use and find out if they can be paralleled. – BrettAM Jul 14 '14 at 19:10
  • yes the more I think about it I really dont need 8 amps 2-4 is enough. Thanks:) – Trexter Jul 14 '14 at 21:07
  • I've heard that the BECs on some ESCs don't always output a smooth 5v and it can vary with how much power is being used by the motors. Perhaps that could cause the arduino to crash? – m3z Jul 16 '14 at 7:34
  • so do you think that a regulator is necessary – Trexter Jul 16 '14 at 17:52
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    A regulator is what a BEC IS. The built-in thing in your ESC is typically a linear voltage regulator, and they are extremely unreliable and should not be used to power critical equipment on your aircraft. Just don't do it. In fact I recommend disconnecting the middle wires on your ESCs, to permanently disable the on-board regulators, as they aren't needed for anything really. Power your Arduino and RC receiver from a separate 5V regulator, preferably switching type (Castle Creations), connected to the main battery. – Jasmine Jul 17 '14 at 0:16
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Your question is quite long. I've broken it up into several parts:

whether or not it is safe to have a common ground on arduino with an 8 amp power supply

Yes. In fact, if you have any electrical connection (even a signal) between those two, you'll need a common ground to ensure integrity of the data being sent.

if it is safe to use a 5 volt 8 amp power supply with these sensors.

I didn't see how much they drew. Without a lot of information, I'm going to say yes. If you don't need that much current, consider removing one of them so you only have 6A or 4A, since 8A is quite a bit if you aren't using it (and you might waste electricity in the conversion process). Make sure to have a thick enough wire for it. A best practice scenario would be to use each ESC separately or use two of the ESCs in parallel (with all of the grounds connected!). This would isolate the current to either 4A or 2A.

while powering my IMU off the BEC and sending motor PWM signals my sketch would run for about 10 seconds then freeze. It was not until i powered my IMU off the arduinos 5 volt power that I was able to run the sketch flawlessly. What could have been causing that?

I'm not quite sure what would be causing that without seeing the code/circuit for that. The only thing I can think of is the grounds weren't connected and the signal got corrupted.

  • Thank you for taking time to answer this question you have been really helpful. – Trexter Jul 14 '14 at 21:08

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