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  #11  
Old 06-11-2018, 02:46 PM
rv7charlie rv7charlie is offline
 
Join Date: May 2006
Location: Pocahontas MS
Posts: 3,014
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Justin,

If all your connections are perfect, there will be no practical difference between grounding on the starter vs grounding on an engine bolt somewhere. But, occasionally someone has issues with paint/powder coating/etc on the starter, engine case, etc and that can drive up the resistance on the ground path. If that's a concern, go for the starter itself.

On grounding through the motor mount: running DC current through the steel mount can tend to magnetize it, which can sometimes give a panel mounted compass fits and be really hard to find. And you've added several more joints to your ground path.

FWIW...
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  #12  
Old 06-13-2018, 02:09 PM
AviatorJ AviatorJ is offline
 
Join Date: Feb 2015
Location: Oklahoma City
Posts: 663
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Thanks again. I'm changing up my original idea, I'll now have essentially a #2 (Which I learned is different than 2/0) cable from the battery in the tail to master contactor, to starter contactor to Skytec starter.

For ground, another #2 from the ground lug on the Skytec starter to the buss bolt in the firewall, to a ground strip, and back to the negative connection on the battery.

Majority of grounds will be on the subpanel ground strip (be it one or several) and the few items in the tail will either be chained to the front or have separate smaller ground wires ran up.

No more grounding to the engine mount or the engine (outside of the starter).
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RV-10 Quickbuild 'Avionics and Interior'
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  #13  
Old 06-13-2018, 03:42 PM
rv7charlie rv7charlie is offline
 
Join Date: May 2006
Location: Pocahontas MS
Posts: 3,014
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If you don't have a good grasp on the 'whys' of grounding methods, be a bit cautious on how you distribute multiple forests of tabs.

This is a gross oversimplification, but look at the 'geography' (physical layout) of what you plan to do. Try not to get ground paths from noise makers (strobes, LED power supplies, DC motors, etc) running past the ground points of low energy items like radios, intercoms, etc, on their way back to the battery.

Example: Strobe and comm radio ground to a tab at A, which has its ground path daisy chained to B (where the intercom is grounded), and then to the battery negative. If this happens, strobe ground currents can 'modulate' the audio signal ground return signal between the radio and intercom. So you hear strobe noise in either the comm, or intercom, or both.

And if you ground each forest locally to the airframe, that can have the same effect as that daisy chained ground, depending on where each forest of tabs is located.
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