ESC Flight batt and rx batt grounding...

[fran11784]

Hey guys, has anyone ever heard of doing this?

In scale configurations main battery power wires may be
longer than on comparable 3D helicopter equipment. As HV
ESCs do not necessarily have the main battery ground wire
connected to the servo signal ground wire, it may be
necessary to create an additional connection between the
BEC 2S batteries ground wire and the 12S main battery
ground wire. Certain configurations without this ground
interconnection have led to a loss of signal at the ESC from
the receiver due to EMC effects.

This is another Roban project I'm working on and came across this in the manual. Thanks, T

 

[Smoggie]

What ESC are you using? Not all HV ESC's are OPTO (Optically isolated)

It's a fair point that with a true OPTO ESC when powering the Rx from a seperate battery then the grounds of the main flight battery and that of the Rx battery won't be connected, so you could build up a voltage between the two.

 

[fran11784]

I will be useing a CC Edge 120. No internal BEC. And a separate 2s pack

 

[Smoggie]

I'm not sure if the Edge 120HV is 'OPTO'.. The previous 'ICE HV' range were but the spec for the Edge doesnt say. You can test it by checking for continuity between the pin on the black wire of the throttle lead and the black wire on the battery connection. If it's open circuit it's OPTO.

However, I used that exact same ESC on one of my helis with the Rx powered by a seperate battery and I had no trouble.

 

[fran11784]

Thanks smoggie, I will check that. All my helicopters use a separate 2s lipo and all are CC Edge's. Never had an issue but reading that makes me want to be sure. Always learning something new

 

[jcfernan51]

I did a quick search on CC web site and I don't think the Edge 120 is Opto isolated but I am running a CC edge 160 HV with a separate Rx battery with no issues in my 700L

 

[fran11784]

Just checked the ESC. There IS continuity between the large battery ground and the ground on the servo connector ground wire. If I'm reading that paragraph right they want it to have continuity?? I don't think in this model the wires will be any longer then a ordinary pod and boom heli.

 

[Smoggie]

If there is continuity then the ESC is not 'OPTO' so there is no concern. The two sides of the ESC are already connected to a common ground so you don't need to do anything.

True OPTO was important back in the day of FM radio systems where the isolation prevented transmission of noise from the ESC being transmitted down the throttle wire and interfering with the receiver. With modern 2.4GHz systems it's not an issue.

 

[fran11784]

Ok thanks for the help. As mentioned, I never had any issue with any of my CC ESC's except for one ICE2 that went on fire......lol Thanks again