New to flying r/c

[sprzout]

ANOTHER question...

If I wanted to power 2 escs separately(for whatever reason), but still have them connected to the same rx, would I just remove the 5v pin from one of the BEC plugs?

I ran into a similar problem with my robot but I can't remember the verdict.

Nope, don't need to do that...Take a watch of the FT Sea Duck build video; Josh Bixler actually goes through that with the electronics. If you're trying to do differential thrust, you'll need to have a Y-splitter for power (in the case of the Sea Duck, you have 2 separate XT-60 plugs that go into one XT-60 plug that connects to your battery) and then each ESC connects into your receiver on a separate channel.

Here's pretty much the start of the ESC setup for differential thrust; you won't need to disable any wiring for it:

Here's one on Differential Thrust:

https://www.flitetest.com/articles/how-to-program-differential-thrust

Hopefully this helps - I know how to set it up, but explaining it can be a little difficult; Josh does a better job of laying it out than I can.

 

[Morgajus]

Nope, don't need to do that...Take a watch of the FT Sea Duck build video; Josh Bixler actually goes through that with the electronics. If you're trying to do differential thrust, you'll need to have a Y-splitter for power (in the case of the Sea Duck, you have 2 separate XT-60 plugs that go into one XT-60 plug that connects to your battery) and then each ESC connects into your receiver on a separate channel.

Here's pretty much the start of the ESC setup for differential thrust; you won't need to disable any wiring for it:

Here's one on Differential Thrust:

https://www.flitetest.com/articles/how-to-program-differential-thrust

Hopefully this helps - I know how to set it up, but explaining it can be a little difficult; Josh does a better job of laying it out than I can.

So I plan to make the y-harness and run seperate channels, even bought the xt-60 plugs and wire already. But my question was more of a "would it work" type question.

Like if I was running one esc off a 3s 1100mah and another one off a 3s 2200mah pack, could I pull the 5v lead from one side and send signal to both escs? Ignore what the escs would be powering in turn for this hypothetical scenario... I can't really think of a good reason to do this over the y-harness, but i needs tah know!

 

[sprzout]

So I plan to make the y-harness and run seperate channels, even bought the xt-60 plugs and wire already. But my question was more of a "would it work" type question.

Like if I was running one esc off a 3s 1100mah and another one off a 3s 2200mah pack, could I pull the 5v lead from one side and send signal to both escs? Ignore what the escs would be powering in turn for this hypothetical scenario... I can't really think of a good reason to do this over the y-harness, but i needs tah know!

Don't try to run 2 separate battery packs. That's adding unnecessary weight, and there's no benefit to running them. In addition, two different sized batteries will simply cause one to run lower or potentially fail before the other. Even if they were the same size, there is no benefit to two unless you're running them to try and get the equivalent of a 6s battery for power - which could potentially burn out your ESCs and or motors unless you're trying to use an EDF with a 60a ESC or higher in a LARGE airframe (and by large, I mean something giant scale).

As for pulling the 5v lead, you can try it, but I think that all you'll be doing is turning off the BEC for that ESC, and negating the use of the battery to that particular circuit.

 

[Morgajus]

Don't try to run 2 separate battery packs. That's adding unnecessary weight, and there's no benefit to running them. In addition, two different sized batteries will simply cause one to run lower or potentially fail before the other. Even if they were the same size, there is no benefit to two unless you're running them to try and get the equivalent of a 6s battery for power - which could potentially burn out your ESCs and or motors unless you're trying to use an EDF with a 60a ESC or higher in a LARGE airframe (and by large, I mean something giant scale).

As for pulling the 5v lead, you can try it, but I think that all you'll be doing is turning off the BEC for that ESC, and negating the use of the battery to that particular circuit.

*slowly smacking head on desk*
sorry, it's been a very long day...
I think, I'm failing to communicate my question effectively...

so then, first, some history:
We built an r/c robot for an engineering course a little while back. Using an arduino to take the signal from the rx and convert it to signal for our 2 motor controllers. one method we considered was using separate batteries for the drive system controller (30A) and the tool-arm controller (2A). This would have been done to allow us to increase the voltage/speed for the drives without burning out our arm motors.

Nothing to do with any aircraft that I plan to build

A simple version of the circuit would have looked like this:
Battery1->2A controller[arm]->5v bec to arduino ->receiver
Battery2->30A controller[drive]->bec w/o 5v to arduino-^

Side note: we didn't do this on the bot, ran out of power part-way through the course (which is why I want to know), and still took 4th out of 16 teams.

What we did looked like this:
Battery1 -> controllers (3 @ 2 Amps each) in parallel->5v+bec (+ and GND in parallel) to arduino->rx

We are mechanical engineering students, not electrical engineers so we couldn't be sure if it would fry the arduino/rx or not.

Please excuse any excess sass or crude methodology.

 

[Hai-Lee]

*slowly smacking head on desk*
sorry, it's been a very long day...
I think, I'm failing to communicate my question effectively...

so then, first, some history:
We built an r/c robot for an engineering course a little while back. Using an arduino to take the signal from the rx and convert it to signal for our 2 motor controllers. one method we considered was using separate batteries for the drive system controller (30A) and the tool-arm controller (2A). This would have been done to allow us to increase the voltage/speed for the drives without burning out our arm motors.

Nothing to do with any aircraft that I plan to build

A simple version of the circuit would have looked like this:
Battery1->2A controller[arm]->5v bec to arduino ->receiver
Battery2->30A controller[drive]->bec w/o 5v to arduino-^

Side note: we didn't do this on the bot, ran out of power part-way through the course (which is why I want to know), and still took 4th out of 16 teams.

What we did looked like this:
Battery1 -> controllers (3 @ 2 Amps each) in parallel->5v+bec (+ and GND in parallel) to arduino->rx

We are mechanical engineering students, not electrical engineers so we couldn't be sure if it would fry the arduino/rx or not.

Please excuse any excess sass or crude methodology.

I agree with @sprzout you should run both controllers and motors from a single battery power source or at least from two equal capacity batteries, (if you are not running the batteries flat in flight).

The issue with different sized batteries is going to be the discharge currents and each battery's internal resistance. The ESCs supply current to the motors and the battery provides the voltage. With one large and one small battery the internal resistances will mean that the smaller battery will supply lower voltage for the same discharge current and it will also run hotter. By running hotter its life will be shorter.

If not using a differential thrust setup to allow for differences in thrust from each motor installation you could easily suffer from EXTREME thrust induced adverse yaw which no rudder will be able to compensate for.

The only twin motor installation that would be stable under your plan as currently outlined would be a push-pull setup!

have fun!

 

[Morgajus]

I agree with @sprzout you should run both controllers and motors from a single battery power source or at least from two equal capacity batteries, (if you are not running the batteries flat in flight).

The issue with different sized batteries is going to be the discharge currents and each battery's internal resistance. The ESCs motor controllers supply current and modulated voltage to the motors and the battery provides the max voltage and current. With one large and one small battery the internal resistances will mean that the smaller battery will supply lower voltage for the same discharge current and it will also run hotter. By running hotter its life will be shorter.

If not using a differential thrust setup to allow for differences in thrust from each motor installation you could easily suffer from EXTREME thrust induced adverse yaw which no rudder will be able to compensate for.

The only twin motor installation that would be stable under your plan as currently outlined would be a push-pull setup!

have fun!

So what your saying, after editing away all the aircraft parts and/or replacing them with the applicable robot components, is that it might work, but it would probably kill the smaller battery. Right? The only interaction the batteries would have would be through the BECs attached to the arduino.
The equal capacity would have been doable. 2-3s 1600mah for the arm (5-12v, 100kv motor) and 4s 1600mah for the drives (4x 9-18v 970kv motors).

Everything you've said about planes also sounds perfectly reasonable and I will try to add it to my tool belt for the future. Thank you.