Replies to This Discussion

Permalink Reply by Ted Van Slyck on March 23, 2012 at 7:43am

I noticed you are only running the BEC from one ESC to the APM. I've read somewhere in the past that is how youre supposed to do it, but apparently it is too much draw for your ESC. I simply plug all the stock wires from my ESC's into my APM. So essentially the BEC's are all running in parallel (the power comes into the signal output ports of the APM). I have been doing this for a long time with no issues. APM 1 if it matters. My ESC's are simply all wired in parallel with wires, no PDB. 

Ive been flying model airplanes for a long time and have seen more than one built in BEC go bad during use do to high load. If you overload that BEC it will fail. 

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ModeratorPermalink Reply by Graham Dyer on March 23, 2012 at 7:57am

Likewise I run all ESC's in parallel on APM2, but that's against the general consensus though. Also been flying planes a long time and am running ESC's in parallel on a number of twins. One of the concerns is that the ESC's heat up, wasting energy, but I've seen no evidence of my ESC's getting any warmer than usual (if fact, they feel cooler actually) and the benefit is more current available to the system.

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Permalink Reply by Dustin on March 23, 2012 at 12:50pm

The reason you are only supposed to run one ESC to the APM is because if they are at diffent voltages (and they will be -- due to variations in parts, incorrect programming, heat differences, or failures), the higher voltages will try to charge those with lower voltages.  This can cause all kinds of issues as you don't want an attempt to charge the ESC through it's voltage output wires.  You're lucky it's working w/o any issues.

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Permalink Reply by Ian forbes on March 23, 2012 at 10:21am

WILL ONE OF THE APM GURUS PLEASE help me RESOLVE THIS WIRING! Exaust and Graham you guys are doing it the way I originally had it setup! That is how every rc quad I have recieved was wired... OLD SCHOOL! 

My situation is complicated by the blown power diode on the motor side of the APM. I have since rewired to the following configuration.

I am getting frustrated as I get mixed stories on how to do wiring.  I have read also that you only want one power and ground going to whatever leg of electronics you are running.  i.e. only one sig /powr /ground going to motors. As I understand it this is because ground loops cause noise that can interfere with APM. I hve bench tested and none of the esc becs are getting hot now, so I think this will work, but I need some expert advice at this point.

 

 

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Permalink Reply by Dustin on March 23, 2012 at 12:52pm

The only thing I would do differently is to tie together the ground wires from all ESC's.  It's the positive wire wires that you don't want to connect together.  In my opinion, they should have a common ground.

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Permalink Reply by Ian forbes on March 23, 2012 at 12:59pm

Theoretically don't the esc's go to common ground to the battery though as direct pass through, in other words it is the power out of esc that is regulated not affecting the ground??? 

 

And since each item is being grounded by the individual esc, wouldn't it be redundant?  As it is now wired the APM2 only has one ground and one power going through the input side of the board.   

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Permalink Reply by Dustin on March 23, 2012 at 5:49pm

I think you are asking... "since the DC inputs have a common ground, won't the DC outputs automatically have a common ground".  If so, that is a logical thought process, however, with so many different ESC designs, I don't feel comfortable betting on that assumption. 

It is certainly possible to design a circuit with floating voltages, and since we don't get to see the circuit diagrams of the ESC's, I couldn't say for sure that it would be true with all ESCs.  However, it would be easy enough to determine by putting an ohm-meter on the input ground and the output ground of your particular ESC's to see if the output voltage is floating or tied to a common ground within the ESCs.  If it reads 0 ohms, then, for that ESC, the input and output grounds are tied together.

Also, can you please explain what you mean by "blew power diode on the motor side".  The brushless motors run off AC voltages.  Diodes work with DC voltages, so I'm not clear what blew.

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Permalink Reply by Ian forbes on March 23, 2012 at 6:26pm

I am unfortunately not strong in my electronics teminology.  Let me phrase it this way, when I connect a lead from an esc (GRd pwr sig) I get no power through the rest of the board.  See

http://diydrones.com/forum/topics/board-issues-when-power-gets-low-....

 

Not sure what happened, but I blew something, so to speak:).  The little 2 pin jumper is still in place, no power gets through the motor side of the board period, I worked around by powering the radio side of the board, seems to work fine.

 

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Permalink Reply by Dave on March 24, 2012 at 12:03pm

Why does your Video TX have 2 power supplies, regulated and unregulated ? that could be and issue as well as the grounds mentioned alerady.

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Permalink Reply by Dustin on March 24, 2012 at 8:27pm

He's right.  I didn't notice that.  Having two powers to the Video doesn't make sense.

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Permalink Reply by Ellison Chan on March 24, 2012 at 12:12pm

Here's what I recommend to those who are running as much equipment off one power supply get a separate BEC capable of powering all that stuff up, like this one:

Most ESC have 2A BECs and with all that equipment hanging of it, they may be overloaded.

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Permalink Reply by Dustin on March 24, 2012 at 8:24pm

This is a good suggestion.  I use a separate BEC (Castle Creations - http://www.amazon.com/Castle-Creations-CASTLE-BEC-010-0004-00/dp/B0...) to power my electronic equipment.  I'm not even using the power from the ESCs.  You really need to check your ESCs though and make sure they are programmed correctly, or your copter may fall out of the sky.

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