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Grounding question

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ogdenk

Joined: 05 Feb 2007
Posts: 41
Location: Syracuse, NY

Posted: Thu Oct 19, 2017 7:28 am Post subject: Grounding question

All,

I have a question/concern regarding a ground return to the battery.  I have primed all my parts and skins with the Akzo Nobel 2 part primer, which is awesome stuff though it's a smelly pain to work with.  All skin overlaps have been primed on both sides of the overlap, and this stuff is not conductive at all so the only electrical path is through the rivets and the small area of the rivet hole that doesn't always have primer covering it.  On the outside of the plane the rivet heads have contact directly with the unprimed skin so it's really the inside skin where there is minimal area in electrical contact.

I am concerned that using the skin as a ground return to the battery may not provide an excellent ground path, especially for the large currents needed for engine cranking.  I would really rather not have to run another heavy wire to the front of the airplane for ground, but I will if necessary.

Has anyone else faced this issue and had a problem (or no problem) using the skin as a ground return?  Also, where/how have people connected the battery ground to the tailcone skin, do you use a piece of brass or copper buss bar riveted to the bottom skin or something like that?

Thanks for any suggestions!

Kent Ogden

#40710 ultra slow-build

civengpe

Joined: 14 Feb 2011
Posts: 105

Posted: Thu Oct 19, 2017 7:37 am Post subject: Grounding question

I used a forest of tabs mounted to my firewall with a #2 (I think) cable run from there all the way back to the battery ground in the tailcone.Â  I'm not sure if it was overkill, but I have had zero issues so far.Â Â 



I think the plans ground path is through the skin to the battery tray where you ground the battery.Â Â 

http://www.bandc.aero/grounding-supplies-battery-cables.aspx

ShannonÂ 



On Thu, Oct 19, 2017 at 10:27 AM, Kent Ogden <ogdenk(at)upstate.edu (ogdenk(at)upstate.edu)> wrote:

 	  Quote: 	
		      All,

I have a question/concern regarding a ground return to the battery.Â  I have primed all my parts and skins with the Akzo Nobel 2 part primer, which is awesome stuff though it's a smellyÂ pain to work with.Â  All skin overlaps have been primed on both sides of the overlap, and this stuff is not conductive at all so the only electrical path is through the rivets and the small area of the rivet hole that doesn't always have primer covering it.Â  On the outside of the planeÂ the rivet heads have contact directly with the unprimed skin so it's really the inside skin where there is minimal area in electrical contact.

I am concerned that using the skin as a ground return to the battery may not provide an excellent ground path, especially for the large currents needed for engine cranking.Â  I would really rather not have to run another heavy wire to the front of the airplane for ground, but I will if necessary.

Has anyone else faced this issue and had a problem (or no problem) using the skin as a ground return?Â  Also, where/how have people connected the battery ground to the tailcone skin, do you use a piece of brass or copper buss bar riveted to the bottom skin or something like that?

Thanks for any suggestions!

Kent Ogden

#40710 ultra slow-build

philperry9

Joined: 23 Nov 2011
Posts: 381

Posted: Thu Oct 19, 2017 7:43 am Post subject: Grounding question

Ditto



Sent from my iPhone



On Oct 19, 2017, at 10:35 AM, Shannon Hicks <civeng123(at)gmail.com (civeng123(at)gmail.com)> wrote:

 	  Quote: 	
		  I used a forest of tabs mounted to my firewall with a #2 (I think) cable run from there all the way back to the battery ground in the tailcone.  I'm not sure if it was overkill, but I have had zero issues so far.  



I think the plans ground path is through the skin to the battery tray where you ground the battery.  

http://www.bandc.aero/grounding-supplies-battery-cables.aspx

Shannon 



On Thu, Oct 19, 2017 at 10:27 AM, Kent Ogden <ogdenk(at)upstate.edu (ogdenk(at)upstate.edu)> wrote:

 	  Quote: 	
		      All,

I have a question/concern regarding a ground return to the battery.  I have primed all my parts and skins with the Akzo Nobel 2 part primer, which is awesome stuff though it's a smelly pain to work with.  All skin overlaps have been primed on both sides of the overlap, and this stuff is not conductive at all so the only electrical path is through the rivets and the small area of the rivet hole that doesn't always have primer covering it.  On the outside of the plane the rivet heads have contact directly with the unprimed skin so it's really the inside skin where there is minimal area in electrical contact.

I am concerned that using the skin as a ground return to the battery may not provide an excellent ground path, especially for the large currents needed for engine cranking.  I would really rather not have to run another heavy wire to the front of the airplane for ground, but I will if necessary.

Has anyone else faced this issue and had a problem (or no problem) using the skin as a ground return?  Also, where/how have people connected the battery ground to the tailcone skin, do you use a piece of brass or copper buss bar riveted to the bottom skin or something like that?

Thanks for any suggestions!

Kent Ogden

#40710 ultra slow-build

Dave Saylor

Joined: 11 Jan 2015
Posts: 209
Location: GILROY, CA

Posted: Thu Oct 19, 2017 7:52 am Post subject: Grounding question

Kent,



There are so many rivets making metal-on-metal contact that I can't imagine there'd be any problem, even with primed skins.

If you want a more of a one-piece conductor, you could use one of the long stringers as a return with a flexible conductor on each end.

I likeÂ braided ground straps.Â  Mine is bolted to a vertical member of the baggage floor just forward of the battery.

--Dave

On Thu, Oct 19, 2017 at 8:27 AM, Kent Ogden <ogdenk(at)upstate.edu (ogdenk(at)upstate.edu)> wrote:

 	  Quote: 	
		      All,

I have a question/concern regarding a ground return to the battery.Â  I have primed all my parts and skins with the Akzo Nobel 2 part primer, which is awesome stuff though it's a smellyÂ pain to work with.Â  All skin overlaps have been primed on both sides of the overlap, and this stuff is not conductive at all so the only electrical path is through the rivets and the small area of the rivet hole that doesn't always have primer covering it.Â  On the outside of the planeÂ the rivet heads have contact directly with the unprimed skin so it's really the inside skin where there is minimal area in electrical contact.

I am concerned that using the skin as a ground return to the battery may not provide an excellent ground path, especially for the large currents needed for engine cranking.Â  I would really rather not have to run another heavy wire to the front of the airplane for ground, but I will if necessary.

Has anyone else faced this issue and had a problem (or no problem) using the skin as a ground return?Â  Also, where/how have people connected the battery ground to the tailcone skin, do you use a piece of brass or copper buss bar riveted to the bottom skin or something like that?

Thanks for any suggestions!

Kent Ogden

#40710 ultra slow-build

_________________
--Dave
KWVI

Tim Olson

Joined: 25 Jan 2007
Posts: 2878

Posted: Thu Oct 19, 2017 7:59 am Post subject: Grounding question

+1.   I ran an independent #2 ground.



That said, with the number of rivets in the airframe I'm sure you'll be 

fine as long as you ground to something with a lot of rivets in it.

I just wanted as low a resistance path to my forest of tabs as

possible.



Tim

On 10/19/2017 10:42 AM, Phillip Perry wrote:

 	  Quote: 	
		   Ditto

 

 Sent from my iPhone

 

 On Oct 19, 2017, at 10:35 AM, Shannon Hicks <civeng123(at)gmail.com 

 <mailto:civeng123(at)gmail.com>> wrote:

 

> I used a forest of tabs mounted to my firewall with a #2 (I think) 

> cable run from there all the way back to the battery ground in the 

> tailcone.Â  I'm not sure if it was overkill, but I have had zero issues 

> so far.

>

> I think the plans ground path is through the skin to the battery tray 

> where you ground the battery.

>

> http://www.bandc.aero/grounding-supplies-battery-cables.aspx

>

> Shannon

>

> On Thu, Oct 19, 2017 at 10:27 AM, Kent Ogden <ogdenk(at)upstate.edu 

> <mailto:ogdenk(at)upstate.edu>> wrote:

>

>     All,

>

>     I have a question/concern regarding a ground return to the

>     battery.Â  I have primed all my parts and skins with the Akzo Nobel

>     2 part primer, which is awesome stuff though it's a smellyÂ pain to

>     work with.Â  All skin overlaps have been primed on both sides of

>     the overlap, and this stuff is not conductive at all so the only

>     electrical path is through the rivets and the small area of the

>     rivet hole that doesn't always have primer covering it.Â  On the

>     outside of the planeÂ the rivet heads have contact directly with

>     the unprimed skin so it's really the inside skin where there is

>     minimal area in electrical contact.

>

>     I am concerned that using the skin as a ground return to the

>     battery may not provide an excellent ground path, especially for

>     the large currents needed for engine cranking.Â  I would really

>     rather not have to run another heavy wire to the front of the

>     airplane for ground, but I will if necessary.

>

>     Has anyone else faced this issue and had a problem (or no problem)

>     using the skin as a ground return?Â  Also, where/how have people

>     connected the battery ground to the tailcone skin, do you use a

>     piece of brass or copper buss bar riveted to the bottom skin or

>     something like that?

>

>     Thanks for any suggestions!

>

>     Kent Ogden

>     #40710 ultra slow-build 

>

Lenny Iszak

Joined: 23 Mar 2008
Posts: 270

Posted: Thu Oct 19, 2017 8:37 am Post subject: Grounding question

I originally ran a #2 wire to the firewall forest of tabs, then realized how much it weighs, promptly ripped it all out and grounded the battery to the battery tray/bellcrank mount (F-1035). It worked out great.



I think itâ€™s more important that you ground everything else to a single point like the forest of tabs on the firewall. I have my tail strobe locally grounded at the end of the tail and it's making a slight audible noise. Everything else is quiet.



Lenny



 	  Quote: 	
		   On Oct 19, 2017, at 11:58 AM, Tim Olson <Tim(at)MyRV10.com> wrote:

 

 

 

 +1.   I ran an independent #2 ground.

 

 That said, with the number of rivets in the airframe I'm sure you'll be fine as long as you ground to something with a lot of rivets in it.

 I just wanted as low a resistance path to my forest of tabs as

 possible.

 

 Tim

 

 

 On 10/19/2017 10:42 AM, Phillip Perry wrote:

> Ditto

> Sent from my iPhone

> On Oct 19, 2017, at 10:35 AM, Shannon Hicks <civeng123(at)gmail.com <mailto:civeng123(at)gmail.com>> wrote:

>> I used a forest of tabs mounted to my firewall with a #2 (I think) cable run from there all the way back to the battery ground in the tailcone.  I'm not sure if it was overkill, but I have had zero issues so far.

>> 

>> I think the plans ground path is through the skin to the battery tray where you ground the battery.

>> 

>> http://www.bandc.aero/grounding-supplies-battery-cables.aspx

>> 

>> Shannon

>> 

>> On Thu, Oct 19, 2017 at 10:27 AM, Kent Ogden <ogdenk(at)upstate.edu <mailto:ogdenk(at)upstate.edu>> wrote:

>> 

>>    All,

>> 

>>    I have a question/concern regarding a ground return to the

>>    battery.  I have primed all my parts and skins with the Akzo Nobel

>>    2 part primer, which is awesome stuff though it's a smelly pain to

>>    work with.  All skin overlaps have been primed on both sides of

>>    the overlap, and this stuff is not conductive at all so the only

>>    electrical path is through the rivets and the small area of the

>>    rivet hole that doesn't always have primer covering it.  On the

>>    outside of the plane the rivet heads have contact directly with

>>    the unprimed skin so it's really the inside skin where there is

>>    minimal area in electrical contact.

>> 

>>    I am concerned that using the skin as a ground return to the

>>    battery may not provide an excellent ground path, especially for

>>    the large currents needed for engine cranking.  I would really

>>    rather not have to run another heavy wire to the front of the

>>    airplane for ground, but I will if necessary.

>> 

>>    Has anyone else faced this issue and had a problem (or no problem)

>>    using the skin as a ground return?  Also, where/how have people

>>    connected the battery ground to the tailcone skin, do you use a

>>    piece of brass or copper buss bar riveted to the bottom skin or

>>    something like that?

>> 

>>    Thanks for any suggestions!

>> 

>>    Kent Ogden

>>    #40710 ultra slow-build 

>> 

>> 

>>

_________________
Lenny Iszak
Palm City, FL
2014 RV-10, N311LZ - 500 hrs

rnewman(at)tcwtech.com
Guest

Posted: Thu Oct 19, 2017 8:48 am Post subject: Grounding question

I used the same Akzo Noble primer on my RV-10, all skins are primed including both sides of all lap joints.  ( This primer is amazing stuff, does stink like all heck, but really tough and protective.   Weâ€™ve used this on the eight airplanes we have built now over more than 20 years now,  and can say it has held up extremely well.)  

I did not run a separate #2 wire up to the front.     All ground current for the starter, alternator and engine sensors flows back through the airframe.   I do have a #8 ground wire running from the battery to a ground bus up under the instrument panel solely for the avionics.  



I have absolutely no electrical issues or noise problems in this airplane.  



Bob Newman

TCW Technologies, LLC

610-928-3420



 	  Quote: 	
		   On Oct 19, 2017, at 11:58 AM, Tim Olson <Tim(at)MyRV10.com> wrote:

 

 

 

 +1.   I ran an independent #2 ground.

 

 That said, with the number of rivets in the airframe I'm sure you'll be fine as long as you ground to something with a lot of rivets in it.

 I just wanted as low a resistance path to my forest of tabs as

 possible.

 

 Tim

 

 

> On 10/19/2017 10:42 AM, Phillip Perry wrote:

> Ditto

> Sent from my iPhone

>> On Oct 19, 2017, at 10:35 AM, Shannon Hicks <civeng123(at)gmail.com <mailto:civeng123(at)gmail.com>> wrote:

>> I used a forest of tabs mounted to my firewall with a #2 (I think) cable run from there all the way back to the battery ground in the tailcone.  I'm not sure if it was overkill, but I have had zero issues so far.

>> 

>> I think the plans ground path is through the skin to the battery tray where you ground the battery.

>> 

>> http://www.bandc.aero/grounding-supplies-battery-cables.aspx

>> 

>> Shannon

>> 

>> On Thu, Oct 19, 2017 at 10:27 AM, Kent Ogden <ogdenk(at)upstate.edu <mailto:ogdenk(at)upstate.edu>> wrote:

>> 

>>    All,

>> 

>>    I have a question/concern regarding a ground return to the

>>    battery.  I have primed all my parts and skins with the Akzo Nobel

>>    2 part primer, which is awesome stuff though it's a smelly pain to

>>    work with.  All skin overlaps have been primed on both sides of

>>    the overlap, and this stuff is not conductive at all so the only

>>    electrical path is through the rivets and the small area of the

>>    rivet hole that doesn't always have primer covering it.  On the

>>    outside of the plane the rivet heads have contact directly with

>>    the unprimed skin so it's really the inside skin where there is

>>    minimal area in electrical contact.

>> 

>>    I am concerned that using the skin as a ground return to the

>>    battery may not provide an excellent ground path, especially for

>>    the large currents needed for engine cranking.  I would really

>>    rather not have to run another heavy wire to the front of the

>>    airplane for ground, but I will if necessary.

>> 

>>    Has anyone else faced this issue and had a problem (or no problem)

>>    using the skin as a ground return?  Also, where/how have people

>>    connected the battery ground to the tailcone skin, do you use a

>>    piece of brass or copper buss bar riveted to the bottom skin or

>>    something like that?

>> 

>>    Thanks for any suggestions!

>> 

>>    Kent Ogden

>>    #40710 ultra slow-build 

>> 

>> 

>>

Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Thu Oct 19, 2017 1:09 pm Post subject: Grounding question

The airframe has plenty of surface area to carry any amount of current 

you will use.

Running a separate cable from the battery to firewall central grounding 

point is a totally wasted effort.

Strobes are a bit different animal if you are talking the old capacitive 

discharge into a flash tube variety. They do generate noise that is hard 

to totally suppress.

LED strobes don't seem to do that.

I have electrical system from battery to VPX system built to plans, with 

grounding cable to frame , in front of battery box.

I have LED nav lights and strobes, all grounded locally, along with Vans 

landing lights grounded locally.

The central grounding is essential for electronics that amplify noises 

such as intercoms, nav coms etc. It is unnecessary for resistive 

electrical loads, as they don't generate RF noise.

My previous aircraft was a Mooney that was built with full zinc chromate 

primer, mostly non-structural skin, and chrome-moly tube frame, with 

battery behind baggage compartment. It was just fine with ground wire to 

airframe at battery. Cessna does the same.



On 10/19/2017 9:35 AM, Lenny Iszak wrote:

 	  Quote: 	
		   

 

 I originally ran a #2 wire to the firewall forest of tabs, then realized how much it weighs, promptly ripped it all out and grounded the battery to the battery tray/bellcrank mount (F-1035). It worked out great.

 R

 I think itâ€™s more important that you ground everything else to a single point like the forest of tabs on the firewall. I have my tail strobe locally grounded at the end of the tail and it's making a slight audible noise. Everything else is quiet.

 

 Lenny

 

> On Oct 19, 2017, at 11:58 AM, Tim Olson <Tim(at)MyRV10.com> wrote:

>

> 

>

> +1.   I ran an independent #2 ground.

>

> That said, with the number of rivets in the airframe I'm sure you'll be fine as long as you ground to something with a lot of rivets in it.

> I just wanted as low a resistance path to my forest of tabs as

> possible.

>

> Tim

> On 10/19/2017 10:42 AM, Phillip Perry wrote:

>> Ditto

>> Sent from my iPhone

>> On Oct 19, 2017, at 10:35 AM, Shannon Hicks <civeng123(at)gmail.com <mailto:civeng123(at)gmail.com>> wrote:

>>> I used a forest of tabs mounted to my firewall with a #2 (I think) cable run from there all the way back to the battery ground in the tailcone.  I'm not sure if it was overkill, but I have had zero issues so far.

>>>

>>> I think the plans ground path is through the skin to the battery tray where you ground the battery.

>>>

>>> http://www.bandc.aero/grounding-supplies-battery-cables.aspx

>>>

>>> Shannon

>>>

>>> On Thu, Oct 19, 2017 at 10:27 AM, Kent Ogden <ogdenk(at)upstate.edu <mailto:ogdenk(at)upstate.edu>> wrote:

>>>

>>>     All,

>>>

>>>     I have a question/concern regarding a ground return to the

>>>     battery.  I have primed all my parts and skins with the Akzo Nobel

>>>     2 part primer, which is awesome stuff though it's a smelly pain to

>>>     work with.  All skin overlaps have been primed on both sides of

>>>     the overlap, and this stuff is not conductive at all so the only

>>>     electrical path is through the rivets and the small area of the

>>>     rivet hole that doesn't always have primer covering it.  On the

>>>     outside of the plane the rivet heads have contact directly with

>>>     the unprimed skin so it's really the inside skin where there is

>>>     minimal area in electrical contact.

>>>

>>>     I am concerned that using the skin as a ground return to the

>>>     battery may not provide an excellent ground path, especially for

>>>     the large currents needed for engine cranking.  I would really

>>>     rather not have to run another heavy wire to the front of the

>>>     airplane for ground, but I will if necessary.

>>>

>>>     Has anyone else faced this issue and had a problem (or no problem)

>>>     using the skin as a ground return?  Also, where/how have people

>>>     connected the battery ground to the tailcone skin, do you use a

>>>     piece of brass or copper buss bar riveted to the bottom skin or

>>>     something like that?

>>>

>>>     Thanks for any suggestions!

>>>

>>>     Kent Ogden

>>>     #40710 ultra slow-build 

>>>

>>>

>>>

>

>

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

Bob Turner

Joined: 03 Jan 2009
Posts: 885
Location: Castro Valley, CA

Posted: Thu Oct 19, 2017 1:39 pm Post subject: Re: Grounding question

As others have said, there should be lots of good metal to metal contact with the rivets - when driven properly, they expand radially against the sides of the holes. But if it worries you, itâ€™s easy to measure. Ground the starter locally, and the same with the negative battery terminal. Run a pair of temporary wires from these locations to a good milli-volt voltmeter in the cockpit. Clear the prop area, and engage the starter. What does the voltmeter read?

_________________
Bob Turner
RV-10 QB

philperry9

Joined: 23 Nov 2011
Posts: 381

Posted: Thu Oct 19, 2017 2:10 pm Post subject: Grounding question

Along that line, itâ€™s important to remember that the conductivity you get today may not be e conductivity you see 3, 5, or 10 years down the road.   As corrosion sets in over time, resistance will increase and circuit performance is degrade. 



If youâ€™re in a highly corrosive environment like those of us along the gulf coast, itâ€™s probably a wise investment to run a dedicated grounding wire.   



We spend way too much time in this area chasing down grounding problems that are frequently caused by corrosion.  Often times, they get fixed by running a dedicated ground to whatever device is having problems.  



Phil





Sent from my iPhone



 	  Quote: 	
		   On Oct 19, 2017, at 4:39 PM, Bob Turner <bobturner(at)alum.rpi.edu> wrote:

 

 

 

 As others have said, there should be lots of good metal to metal contact with the rivets - when driven properly, they expand radially against the sides of the holes. But if it worries you, itâ€™s easy to measure. Ground the starter locally, and the same with the negative battery terminal. Run a pair of temporary wires from these locations to a good milli-volt voltmeter in the cockpit. Clear the prop area, and engage the starter. What does the voltmeter read?

 

 --------

 Bob Turner

 RV-10 QB

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=473693#473693

schmoboy

Joined: 26 Feb 2006
Posts: 130

Posted: Thu Oct 19, 2017 3:26 pm Post subject: Grounding question

Same boat here.  No run from forest on firewall back to batt.  LED nav 

and strobe lights locally grounded.  No issues with those.  But... I do 

have crazy noise when my locally grounded HID landing light ballasts 

heat up at first.  It subsides once the draw rush is over.  Thinking of 

swapping out for LED landing lights anyways, but have been unable to 

make them quiet.



-Sean #40303



 	  Quote: 	
		   Kelly McMullen <mailto:kellym(at)aviating.com>

 October 19, 2017 at 4:08 PM

 



 The airframe has plenty of surface area to carry any amount of current 

 you will use.

 Running a separate cable from the battery to firewall central 

 grounding point is a totally wasted effort.

 Strobes are a bit different animal if you are talking the old 

 capacitive discharge into a flash tube variety. They do generate noise 

 that is hard to totally suppress.

 LED strobes don't seem to do that.

 I have electrical system from battery to VPX system built to plans, 

 with grounding cable to frame , in front of battery box.

 I have LED nav lights and strobes, all grounded locally, along with 

 Vans landing lights grounded locally.

 The central grounding is essential for electronics that amplify noises 

 such as intercoms, nav coms etc. It is unnecessary for resistive 

 electrical loads, as they don't generate RF noise.

 My previous aircraft was a Mooney that was built with full zinc 

 chromate primer, mostly non-structural skin, and chrome-moly tube 

 frame, with battery behind baggage compartment. It was just fine with 

 ground wire to airframe at battery. Cessna does the same.

philperry9

Joined: 23 Nov 2011
Posts: 381

Posted: Thu Oct 19, 2017 3:53 pm Post subject: Grounding question

Just a data point, even with a dedicated ground, my LED nav/strobes did have considerable noise.  So much that it required a wholesale replacement of the lights.  I didnâ€™t discover it until taxiing our for flight #1, so it became the first item I discovered before I ever left the ground.  

Come to find out, it wasnâ€™t a grounding or wiring problem, it was a design problem within the LED.   The LEDâ€™s I had more pulled current when they were on and less when they were off.  This created a surge that also broke the auto-squelch on my GTN750.   So every time they fired, the squelch in my headset broke too. 

This required a new LED design that had a more linear current flow.   So the current would remain constant even in the off cycles.    This addressed the auto-squelch on the GTN.  

The newer Garmin Nav/Comâ€™s donâ€™t have a squelch knob.   They sense the noise floor and then automatically adjust the squelch to match the floor.    With a constant current draw the floor became constant again and the squelch became functional again.  

Just a word of caution as you go shop LEDâ€™s that flash.   My were from a very reputable Certified and Experimental lighting provider and not cheapoâ€™s from Napa.  Itâ€™s good to ask questions about the current flow patterns and not just be current flow; especially if your using newer radios with auto squelch. 

Fortunately the provider I used worked with me to make a swap to a newer LED version relatively painless and simple. 

Sent from my iPhone

 	  Quote: 	
		   On Oct 19, 2017, at 6:23 PM, Sean Stephens <sean(at)stephensville.com> wrote:

 Same boat here.  No run from forest on firewall back to batt.  LED nav and strobe lights locally grounded.  No issues with those.  But... I do have crazy noise when my locally grounded HID landing light ballasts heat up at first.  It subsides once the draw rush is over.  Thinking of swapping out for LED landing lights anyways, but have been unable to make them quiet.

 -Sean #40303

> Kelly McMullen <mailto:kellym(at)aviating.com>

> October 19, 2017 at 4:08 PM

> 

> 

> The airframe has plenty of surface area to carry any amount of current you will use.

> Running a separate cable from the battery to firewall central grounding point is a totally wasted effort.

> Strobes are a bit different animal if you are talking the old capacitive discharge into a flash tube variety. They do generate noise that is hard to totally suppress.

> LED strobes don't seem to do that.

> I have electrical system from battery to VPX system built to plans, with grounding cable to frame , in front of battery box.

> I have LED nav lights and strobes, all grounded locally, along with Vans landing lights grounded locally.

> The central grounding is essential for electronics that amplify noises such as intercoms, nav coms etc. It is unnecessary for resistive electrical loads, as they don't generate RF noise.

> My previous aircraft was a Mooney that was built with full zinc chromate primer, mostly non-structural skin, and chrome-moly tube frame, with battery behind baggage compartment. It was just fine with ground wire to airframe at battery. Cessna does the same.

> 

> 

> 

> 

>

Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Thu Oct 19, 2017 3:54 pm Post subject: Grounding question

If the conductivity of the airframe deteriorates, it means that a *lot* 

of rivets were not driven properly and are going to start smoking soon, 

if they aren't already. I grant you corrosive environments are 

difficult. I sure would want to have a hangar in those locations.



On 10/19/2017 3:08 PM, Phillip Perry wrote:

 	  Quote: 	
		   

 

 Along that line, itâ€™s important to remember that the conductivity you get today may not be e conductivity you see 3, 5, or 10 years down the road.   As corrosion sets in over time, resistance will increase and circuit performance is degrade.

 

 If youâ€™re in a highly corrosive environment like those of us along the gulf coast, itâ€™s probably a wise investment to run a dedicated grounding wire.

 

 We spend way too much time in this area chasing down grounding problems that are frequently caused by corrosion.  Often times, they get fixed by running a dedicated ground to whatever device is having problems.

 

 Phil

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

philperry9

Joined: 23 Nov 2011
Posts: 381

Posted: Thu Oct 19, 2017 4:26 pm Post subject: Grounding question

Thatâ€™s why our gulf coast planes tend to be heavier.  We soak them in primer!   

Itâ€™s better here in Waco than when I was in Houston.  I donâ€™t miss the rust and corrosion on everything.  My hand tools look like trash after years of working down there. 

You could use a new tool in the morning and by the next morning it would have rust forming on it.  

When we move to Waco, being able to keep bread on the counter more than 4 Days was awesome!  

Sent from my iPhone

 	  Quote: 	
		   On Oct 19, 2017, at 6:52 PM, Kelly McMullen <kellym(at)aviating.com> wrote:

 If the conductivity of the airframe deteriorates, it means that a *lot* of rivets were not driven properly and are going to start smoking soon, if they aren't already. I grant you corrosive environments are difficult. I sure would want to have a hangar in those locations.

> On 10/19/2017 3:08 PM, Phillip Perry wrote:

> 

> Along that line, itâ€™s important to remember that the conductivity you get today may not be e conductivity you see 3, 5, or 10 years down the road.   As corrosion sets in over time, resistance will increase and circuit performance is degrade.

> If youâ€™re in a highly corrosive environment like those of us along the gulf coast, itâ€™s probably a wise investment to run a dedicated grounding wire.

> We spend way too much time in this area chasing down grounding problems that are frequently caused by corrosion.  Often times, they get fixed by running a dedicated ground to whatever device is having problems.

> Phil

trigo(at)mail.telepac.pt
Guest

Posted: Fri Oct 20, 2017 12:40 am Post subject: Grounding question

Philip 

Can you share the brand and supplier of your new LED lights?

Thanks

Carlos

Enviado do meu iPhone

No dia 20/10/2017, Ã s 00:52, Phillip Perry <philperry9(at)gmail.com> escreveu:

 	  Quote: 	

 Just a data point, even with a dedicated ground, my LED nav/strobes did have considerable noise.  So much that it required a wholesale replacement of the lights.  I didnâ€™t discover it until taxiing our for flight #1, so it became the first item I discovered before I ever left the ground.  

 Come to find out, it wasnâ€™t a grounding or wiring problem, it was a design problem within the LED.   The LEDâ€™s I had more pulled current when they were on and less when they were off.  This created a surge that also broke the auto-squelch on my GTN750.   So every time they fired, the squelch in my headset broke too. 

 This required a new LED design that had a more linear current flow.   So the current would remain constant even in the off cycles.    This addressed the auto-squelch on the GTN.  

 The newer Garmin Nav/Comâ€™s donâ€™t have a squelch knob.   They sense the noise floor and then automatically adjust the squelch to match the floor.    With a constant current draw the floor became constant again and the squelch became functional again.  

 Just a word of caution as you go shop LEDâ€™s that flash.   My were from a very reputable Certified and Experimental lighting provider and not cheapoâ€™s from Napa.  Itâ€™s good to ask questions about the current flow patterns and not just be current flow; especially if your using newer radios with auto squelch. 

 Fortunately the provider I used worked with me to make a swap to a newer LED version relatively painless and simple. 

 Sent from my iPhone

> On Oct 19, 2017, at 6:23 PM, Sean Stephens <sean(at)stephensville.com> wrote:

> 

> 

> 

> Same boat here.  No run from forest on firewall back to batt.  LED nav and strobe lights locally grounded.  No issues with those.  But... I do have crazy noise when my locally grounded HID landing light ballasts heat up at first.  It subsides once the draw rush is over.  Thinking of swapping out for LED landing lights anyways, but have been unable to make them quiet.

> 

> -Sean #40303

> 

>> Kelly McMullen <mailto:kellym(at)aviating.com>

>> October 19, 2017 at 4:08 PM

>> 

>> 

>> The airframe has plenty of surface area to carry any amount of current you will use.

>> Running a separate cable from the battery to firewall central grounding point is a totally wasted effort.

>> Strobes are a bit different animal if you are talking the old capacitive discharge into a flash tube variety. They do generate noise that is hard to totally suppress.

>> LED strobes don't seem to do that.

>> I have electrical system from battery to VPX system built to plans, with grounding cable to frame , in front of battery box.

>> I have LED nav lights and strobes, all grounded locally, along with Vans landing lights grounded locally.

>> The central grounding is essential for electronics that amplify noises such as intercoms, nav coms etc. It is unnecessary for resistive electrical loads, as they don't generate RF noise.

>> My previous aircraft was a Mooney that was built with full zinc chromate primer, mostly non-structural skin, and chrome-moly tube frame, with battery behind baggage compartment. It was just fine with ground wire to airframe at battery. Cessna does the same.

>> 

>> 

>> 

>> 

>> 

> 

> 

> 

>

sportav8r(at)gmail.com
Guest

Posted: Fri Oct 20, 2017 7:56 am Post subject: Grounding question

Learn something every day - what kind of LED lighting device pulls the same current when off as it does when on, and why would we want it to do so?Â  Please explain.



On Fri, Oct 20, 2017 at 3:59 AM, Carlos Trigo <trigo(at)mail.telepac.pt (trigo(at)mail.telepac.pt)> wrote:

 	  Quote: 	
		  --> RV10-List message posted by: Carlos Trigo <trigo(at)mail.telepac.pt (trigo(at)mail.telepac.pt)>

 

 Philip

 

 Can you share the brand and supplier of your new LED lights?

 

 Thanks

 Carlos

 

 Enviado do meu iPhone

 

 No dia 20/10/2017, Ã s 00:52, Phillip Perry <philperry9(at)gmail.com (philperry9(at)gmail.com)> escreveu:

 

 > --> RV10-List message posted by: Phillip Perry <philperry9(at)gmail.com (philperry9(at)gmail.com)>

 >

 > Just a data point, even with a dedicated ground, my LED nav/strobes did have considerable noise.Â  So much that it required a wholesale replacement of the lights.Â  I didnâ€™t discover it until taxiing our for flight #1, so it became the first item I discovered before I ever left the ground.

 >

 > Come to find out, it wasnâ€™t a grounding or wiring problem, it was a design problem within the LED.Â  Â The LEDâ€™s I had more pulled current when they were on and less when they were off.Â  This created a surge that also broke the auto-squelch on my GTN750.Â  Â So every time they fired, the squelch in my headset broke too.

 >

 > This required a new LED design that had a more linear current flow.Â  Â So the current would remain constant even in the off cycles.Â  Â  This addressed the auto-squelch on the GTN.

 >

 > The newer Garmin Nav/Comâ€™s donâ€™t have a squelch knob.Â  Â They sense the noise floor and then automatically adjust the squelch to match the floor.Â  Â  With a constant current draw the floor became constant again and the squelch became functional again.

 >

 > Just a word of caution as you go shop LEDâ€™s that flash.Â  Â My were from a very reputable Certified and Experimental lighting provider and not cheapoâ€™s from Napa.Â  Itâ€™s good to ask questions about the current flow patterns and not just be current flow; especially if your using newer radios with auto squelch.

 >

 > Fortunately the provider I used worked with me to make a swap to a newer LED version relatively painless and simple.

 >

 >

 >

 > Sent from my iPhone

 >

 >> On Oct 19, 2017, at 6:23 PM, Sean Stephens <sean(at)stephensville.com (sean(at)stephensville.com)> wrote:

 >>

 >> --> RV10-List message posted by: Sean Stephens <sean(at)stephensville.com (sean(at)stephensville.com)>

 >>

 >> Same boat here.Â  No run from forest on firewall back to batt.Â  LED nav and strobe lights locally grounded.Â  No issues with those.Â  But... I do have crazy noise when my locally grounded HID landing light ballasts heat up at first.Â  It subsides once the draw rush is over.Â  Thinking of swapping out for LED landing lights anyways, but have been unable to make them quiet.

 >>

 >> -Sean #40303

 >>

 >>> Kelly McMullen <mailto:kellym(at)aviating.com (kellym(at)aviating.com)>

 >>> October 19, 2017 at 4:08 PM

 >>> --> RV10-List message posted by: Kelly McMullen <kellym(at)aviating.com (kellym(at)aviating.com)>

 >>>

 >>> The airframe has plenty of surface area to carry any amount of current you will use.

 >>> Running a separate cable from the battery to firewall central grounding point is a totally wasted effort.

 >>> Strobes are a bit different animal if you are talking the old capacitive discharge into a flash tube variety. They do generate noise that is hard to totally suppress.

 >>> LED strobes don't seem to do that.

 >>> I have electrical system from battery to VPX system built to plans, with grounding cable to frame , in front of battery box.

 >>> I have LED nav lights and strobes, all grounded locally, along with Vans landing lights grounded locally.

 >>> The central grounding is essential for electronics that amplify noises such as intercoms, nav coms etc. It is unnecessary for resistive electrical loads, as they don't generate RF noise.

 >>> My previous aircraft was a Mooney that was built with full zinc chromate primer, mostly non-structural skin, and chrome-moly tube frame, with battery behind baggage compartment. It was just fine with ground wire to airframe at battery. Cessna does the same.

 >>>

 >>>

 >>>

 >>>

 >>>

 >>

 >>

 >>

 >>

 >

 >

 >

 >

 

 

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philperry9

Joined: 23 Nov 2011
Posts: 381

Posted: Fri Oct 20, 2017 9:10 am Post subject: Grounding question

When I went through it, it they referred to it is a linear current flow.  

Sent from my iPhone



On Oct 20, 2017, at 10:54 AM, Bill Boyd <sportav8r(at)gmail.com (sportav8r(at)gmail.com)> wrote:

 	  Quote: 	
		  Learn something every day - what kind of LED lighting device pulls the same current when off as it does when on, and why would we want it to do so?  Please explain.



On Fri, Oct 20, 2017 at 3:59 AM, Carlos Trigo <trigo(at)mail.telepac.pt (trigo(at)mail.telepac.pt)> wrote:

 	  Quote: 	
		  --> RV10-List message posted by: Carlos Trigo <trigo(at)mail.telepac.pt (trigo(at)mail.telepac.pt)>

 

 Philip

 

 Can you share the brand and supplier of your new LED lights?

 

 Thanks

 Carlos

 

 Enviado do meu iPhone

 

 No dia 20/10/2017, Ã s 00:52, Phillip Perry <philperry9(at)gmail.com (philperry9(at)gmail.com)> escreveu:

 

 > --> RV10-List message posted by: Phillip Perry <philperry9(at)gmail.com (philperry9(at)gmail.com)>

 >

 > Just a data point, even with a dedicated ground, my LED nav/strobes did have considerable noise.  So much that it required a wholesale replacement of the lights.  I didnâ€™t discover it until taxiing our for flight #1, so it became the first item I discovered before I ever left the ground.

 >

 > Come to find out, it wasnâ€™t a grounding or wiring problem, it was a design problem within the LED.   The LEDâ€™s I had more pulled current when they were on and less when they were off.  This created a surge that also broke the auto-squelch on my GTN750.   So every time they fired, the squelch in my headset broke too.

 >

 > This required a new LED design that had a more linear current flow.   So the current would remain constant even in the off cycles.    This addressed the auto-squelch on the GTN.

 >

 > The newer Garmin Nav/Comâ€™s donâ€™t have a squelch knob.   They sense the noise floor and then automatically adjust the squelch to match the floor.    With a constant current draw the floor became constant again and the squelch became functional again.

 >

 > Just a word of caution as you go shop LEDâ€™s that flash.   My were from a very reputable Certified and Experimental lighting provider and not cheapoâ€™s from Napa.  Itâ€™s good to ask questions about the current flow patterns and not just be current flow; especially if your using newer radios with auto squelch.

 >

 > Fortunately the provider I used worked with me to make a swap to a newer LED version relatively painless and simple.

 >

 >

 >

 > Sent from my iPhone

 >

 >> On Oct 19, 2017, at 6:23 PM, Sean Stephens <sean(at)stephensville.com (sean(at)stephensville.com)> wrote:

 >>

 >> --> RV10-List message posted by: Sean Stephens <sean(at)stephensville.com (sean(at)stephensville.com)>

 >>

 >> Same boat here.  No run from forest on firewall back to batt.  LED nav and strobe lights locally grounded.  No issues with those.  But... I do have crazy noise when my locally grounded HID landing light ballasts heat up at first.  It subsides once the draw rush is over.  Thinking of swapping out for LED landing lights anyways, but have been unable to make them quiet.

 >>

 >> -Sean #40303

 >>

 >>> Kelly McMullen <mailto:kellym(at)aviating.com (kellym(at)aviating.com)>

 >>> October 19, 2017 at 4:08 PM

 >>> --> RV10-List message posted by: Kelly McMullen <kellym(at)aviating.com (kellym(at)aviating.com)>

 >>>

 >>> The airframe has plenty of surface area to carry any amount of current you will use.

 >>> Running a separate cable from the battery to firewall central grounding point is a totally wasted effort.

 >>> Strobes are a bit different animal if you are talking the old capacitive discharge into a flash tube variety. They do generate noise that is hard to totally suppress.

 >>> LED strobes don't seem to do that.

 >>> I have electrical system from battery to VPX system built to plans, with grounding cable to frame , in front of battery box.

 >>> I have LED nav lights and strobes, all grounded locally, along with Vans landing lights grounded locally.

 >>> The central grounding is essential for electronics that amplify noises such as intercoms, nav coms etc. It is unnecessary for resistive electrical loads, as they don't generate RF noise.

 >>> My previous aircraft was a Mooney that was built with full zinc chromate primer, mostly non-structural skin, and chrome-moly tube frame, with battery behind baggage compartment. It was just fine with ground wire to airframe at battery. Cessna does the same.

 >>>

 >>>

 >>>

 >>>

 >>>

 >>

 >>

 >>

 >>

 >

 >

 >

 >

 

 

 ====================================

 -List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?RV10-List

 ====================================

  FORUMS -

 eferrer" target="_blank">http://forums.matronics.com

 ====================================

 WIKI -

 errer" target="_blank">http://wiki.matronics.com

 ====================================

 b Site -

           -Matt Dralle, List Admin.

 rel="noreferrer" target="_blank">http://www.matronics.com/contribution

 ====================================

dilsonfrota(at)gmail.com
Guest

Posted: Fri Oct 20, 2017 10:52 am Post subject: Grounding question

Hi Kent and everyone.



In my opinion you don't need to rum a ground cable to your battery, I 

read very good advices regarding that to your answer.



If you allow me; OUT of your question but INSIDE the ground subject



For your instruments and every other equipment that needs power.



Run three ground wires (all of them direct from battery) not from the 

point you grounded your battery.



MASTER GROUND - This ground should be used to every electrically "dirt" 

instruments or lights - IF you have real noisy and pulsing strobos I'd 

consider to have an extra "REALY DIRT MASTER GROUND" also tied directly 

to battery.



AUDIO INSTRUMENT GROUND - It's only for those instruments related to 

audio signals (a transponder should not be tied here, the same for the 

glasses instruments - such as PFDs, MFDs and Skyview screens)



AUDIO GROUND - Used only and only, to ground audio signals and its 

shields. When running ground connections it's highly recommended to run 

these connections instrument to instrument. I mean, run a wire from the 

radio ground up to the audio panel, the same for every other ground 

signal. if he audio panel connector doesn't have have enough pins tie 

all those grounds to a common wire and that wire to the audio unit.



Also insulate from the air frame the ground of the headsets connector.



The general idea is always lay down your wiring as a star. Regarding to 

ground your battery is the center of you galaxy 



I'm ware that seems to be to much, but it isn't, doing that you will 

listen only the sounds that mater.



Best Regards



Dilson



Em 19/10/2017 19:08, Kelly McMullen escreveu:

 	  Quote: 	
		   



 The airframe has plenty of surface area to carry any amount of current 

 you will use.

 Running a separate cable from the battery to firewall central 

 grounding point is a totally wasted effort.

 Strobes are a bit different animal if you are talking the old 

 capacitive discharge into a flash tube variety. They do generate noise 

 that is hard to totally suppress.

 LED strobes don't seem to do that.

 I have electrical system from battery to VPX system built to plans, 

 with grounding cable to frame , in front of battery box.

 I have LED nav lights and strobes, all grounded locally, along with 

 Vans landing lights grounded locally.

 The central grounding is essential for electronics that amplify noises 

 such as intercoms, nav coms etc. It is unnecessary for resistive 

 electrical loads, as they don't generate RF noise.

 My previous aircraft was a Mooney that was built with full zinc 

 chromate primer, mostly non-structural skin, and chrome-moly tube 

 frame, with battery behind baggage compartment. It was just fine with 

 ground wire to airframe at battery. Cessna does the same.



 On 10/19/2017 9:35 AM, Lenny Iszak wrote:

> 

>

> I originally ran a #2 wire to the firewall forest of tabs, then 

> realized how much it weighs, promptly ripped it all out and grounded 

> the battery to the battery tray/bellcrank mount (F-1035). It worked 

> out great.

> R

> I think itâ€™s more important that you ground everything else to a 

> single point like the forest of tabs on the firewall. I have my tail 

> strobe locally grounded at the end of the tail and it's making a 

> slight audible noise. Everything else is quiet.

>

> Lenny

>

>> On Oct 19, 2017, at 11:58 AM, Tim Olson <Tim(at)MyRV10.com> wrote:

>>

>> 

>>

>> +1.Â Â  I ran an independent #2 ground.

>>

>> That said, with the number of rivets in the airframe I'm sure you'll 

>> be fine as long as you ground to something with a lot of rivets in it.

>> I just wanted as low a resistance path to my forest of tabs as

>> possible.

>>

>> Tim

>>

>>

>> On 10/19/2017 10:42 AM, Phillip Perry wrote:

>>> Ditto

>>> Sent from my iPhone

>>> On Oct 19, 2017, at 10:35 AM, Shannon Hicks <civeng123(at)gmail.com 

>>> <mailto:civeng123(at)gmail.com>> wrote:

>>>> I used a forest of tabs mounted to my firewall with a #2 (I think) 

>>>> cable run from there all the way back to the battery ground in the 

>>>> tailcone.Â  I'm not sure if it was overkill, but I have had zero 

>>>> issues so far.

>>>>

>>>> I think the plans ground path is through the skin to the battery 

>>>> tray where you ground the battery.

>>>>

>>>> http://www.bandc.aero/grounding-supplies-battery-cables.aspx

>>>>

>>>> Shannon

>>>>

>>>> On Thu, Oct 19, 2017 at 10:27 AM, Kent Ogden <ogdenk(at)upstate.edu 

>>>> <mailto:ogdenk(at)upstate.edu>> wrote:

>>>>

>>>> Â Â Â  All,

>>>>

>>>> Â Â Â  I have a question/concern regarding a ground return to the

>>>> Â Â Â  battery.Â  I have primed all my parts and skins with the Akzo 

>>>> Nobel

>>>> Â Â Â  2 part primer, which is awesome stuff though it's a smelly 

>>>> pain to

>>>> Â Â Â  work with.Â  All skin overlaps have been primed on both sides of

>>>> Â Â Â  the overlap, and this stuff is not conductive at all so the only

>>>> Â Â Â  electrical path is through the rivets and the small area of the

>>>> Â Â Â  rivet hole that doesn't always have primer covering it.Â  On the

>>>> Â Â Â  outside of the plane the rivet heads have contact directly with

>>>> Â Â Â  the unprimed skin so it's really the inside skin where there is

>>>> Â Â Â  minimal area in electrical contact.

>>>>

>>>> Â Â Â  I am concerned that using the skin as a ground return to the

>>>> Â Â Â  battery may not provide an excellent ground path, especially for

>>>> Â Â Â  the large currents needed for engine cranking.Â  I would really

>>>> Â Â Â  rather not have to run another heavy wire to the front of the

>>>> Â Â Â  airplane for ground, but I will if necessary.

>>>>

>>>> Â Â Â  Has anyone else faced this issue and had a problem (or no 

>>>> problem)

>>>> Â Â Â  using the skin as a ground return?Â  Also, where/how have people

>>>> Â Â Â  connected the battery ground to the tailcone skin, do you use a

>>>> Â Â Â  piece of brass or copper buss bar riveted to the bottom skin or

>>>> Â Â Â  something like that?

>>>>

>>>> Â Â Â  Thanks for any suggestions!

>>>>

>>>> Â Â Â  Kent Ogden

>>>> Â Â Â  #40710 ultra slow-build 

>>>>

>>>>

>>>>

>>

>>

>>

>>

>

Bob Turner

Joined: 03 Jan 2009
Posts: 885
Location: Castro Valley, CA

Posted: Fri Oct 20, 2017 12:23 pm Post subject: Re: Grounding question

 	  sportav8r(at)gmail.com wrote: 	
		  Learn something every day - what kind of LED lighting device pulls the same current when off as it does when on, and why would we want it to do so?Â  Please explain.



	
[/quote]

You cannot just hook an LED up to 12 volts; it will pull a huge current and quickly overheat and fail. For low power lights (like panel) a dropping resistor is used. Very simple and easy, but 90% of the energy ends up in the resistor. Okay for low power lights, but not for position or landing lights. There, something more sophisticated is needed. The usual solution is to pulse the lights on/off, faster than your eye can see, to limit the power and heat build up. Those pulses can radiate RF and cause interference to other electronics. Some circuits add "smoothing" downstream to limit the RF, and provide a lower average current to the LED. So the LED has some average current thru it, while the power supply is pulsed.

_________________
Bob Turner
RV-10 QB

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