Wiring question: I have ESCs/battery pairs mounted quite some distance from the flight controller, and multiple ESCs/batteries distributed about the drone but then put in parallel with small 24gauge wire connecting the batteries (large gauge from battery to its ESC). I want to minimize wiring runs and weight.
Could I combine the ground I use for putting the batteries in parallel, with the ground needed for the ESC signal? Then I just need to run a signal wire to the ESC. So I would then have 3 wires going to each battery ESC pair: Positive for parallel battery connection (16V), signal for ESC from flight controller, shared ground for parallel battery connection and ground for ESC.
Would this work? I’m concerned because I’m taking a ground from batteries before passing through the power module, then a signal wire from the flight controller after the power module steps down from 16V to 5V. I think electrically the grounds are equivalent.
Yes, you can. The ground is just ground, everywhere. The power module measures the current from the positive wire. Make sure all electronics have the same ground. Multiple ground wires on the same board just for making sure that it lets electronics draw sufficient current without any risks.
Edit: I asked one of my colleagues, and he said if the signal part of the ESC is isolated with optocoupler, you have to connect to signal GND to the overall GND of your system. If it is not isolated, you can use only one GND but otherwise, connect the grounds together.
Also, don’t let get fooled by the GND is seen as short-circuited when measuring it with GND. You have to connect them anyway (if the signal part is isolated with optocoupler), @DroneMang FYI.
I don’t believe there is an optocoupler anywhere, I am using KISS 25A ESC’s with mRo Control zero, I plan to use DSHOT 600. A concern pointed out is that if the batteries are out of balance, then there would be current flowing through the positive/negative wire, and then that negative is shared with the ESC signal, so would this current flowing affect the DSHOT or signal received? Would current somehow flow through the ESC signal wiring? Thanks!
FWIW: Old RC flyer here. I always use a twisted Sig and Gnd to each esc for a lot of reasons. This may explain better than I can:
ESC Signal Ground: Yes or No? | WHY THE ANSWER IS YES - YouTube
In my build fc goes only 2 gnd after 6 ESC signal pin connected to fc and I didn’t put gnd ESC to fc and runs fine
Well, it will mostly harm the batteries. Don’t leave them parallelly connected all the time. Only plug them in parallel before a flight.
I don’t think so. DSHOT is a digital protocol.
Of course not
The ground is only a reference at that part.
But it is a good idea to pull ground wire separately just for the signal, which costs probably 0 cents, 1-2 grams.