Today's Message Index:
----------------------
1. 01:40 AM - Re: Grounding question (Carlos Trigo)
2. 08:56 AM - Re: Grounding question (Bill Boyd)
3. 10:10 AM - Re: Grounding question (Phillip Perry)
4. 11:52 AM - Re: Grounding question (Dilson)
5. 01:23 PM - Re: Grounding question (Bob Turner)
Message 1
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| Subject: | Re: 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, s 00:52, Phillip Perry <philperry9@gmail.com> escreveu:
>
> 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 didnt 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 wasnt a grounding or wiring problem, it was a design problem
within the LED. The LEDs 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/Coms dont 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 LEDs that flash. My were from a very
reputable Certified and Experimental lighting provider and not cheapos from Napa.
Its 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@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@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.
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>
>
>
>
Message 2
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| Subject: | Re: 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?
Please explain.
On Fri, Oct 20, 2017 at 3:59 AM, Carlos Trigo <trigo@mail.telepac.pt> wrote
:
>
> Philip
>
> Can you share the brand and supplier of your new LED lights?
>
> Thanks
> Carlos
>
> Enviado do meu iPhone
>
> No dia 20/10/2017, =C3-s 00:52, Phillip Perry <philperry9@gmail.com>
> escreveu:
>
> >
> > Just a data point, even with a dedicated ground, my LED nav/strobes did
> have considerable noise. So much that it required a wholesale replacemen
t
> of the lights. I didn=99t 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 wasn=99t a grounding or wiring problem, it w
as a
> design problem within the LED. The LED=99s I had more pulled curr
ent 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. S
o
> the current would remain constant even in the off cycles. This address
ed
> the auto-squelch on the GTN.
> >
> > The newer Garmin Nav/Com=99s don=99t 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 LED=99s that flash. My we
re from a
> very reputable Certified and Experimental lighting provider and not
> cheapo=99s from Napa. It=99s 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 newe
r
> LED version relatively painless and simple.
> >
> >
> >
> > Sent from my iPhone
> >
> >> On Oct 19, 2017, at 6:23 PM, Sean Stephens <sean@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 swappi
ng
> out for LED landing lights anyways, but have been unable to make them qui
et.
> >>
> >> -Sean #40303
> >>
> >>> Kelly McMullen <mailto:kellym@aviating.com>
> >>> October 19, 2017 at 4:08 PM
> >>>
> >>> The airframe has plenty of surface area to carry any amount of curren
t
> 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 th
at
> 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 noise
s
> such as intercoms, nav coms etc. It is unnecessary for resistive electric
al
> 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 wir
e
> to airframe at battery. Cessna does the same.
> >>>
> >>>
> >>>
> >>>
> >>>
> >>
> >>
> >>
> >>
> >
> >
> >
> >
>
>
===========
===========
===========
===========
===========
>
>
Message 3
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| Subject: | Re: 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@gmail.com> wrote:
>
> Learn something every day - what kind of LED lighting device pulls the sam
e current when off as it does when on, and why would we want it to do so? P
lease explain.
>
>> On Fri, Oct 20, 2017 at 3:59 AM, Carlos Trigo <trigo@mail.telepac.pt> wro
te:
>>
>> Philip
>>
>> Can you share the brand and supplier of your new LED lights?
>>
>> Thanks
>> Carlos
>>
>> Enviado do meu iPhone
>>
>> No dia 20/10/2017, =C3-s 00:52, Phillip Perry <philperry9@gmail.com> es
creveu:
>>
>> >
>> > 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 o
f the lights. I didn=99t 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 wasn=99t a grounding or wiring problem, it w
as a design problem within the LED. The LED=99s I had more pulled cu
rrent when they were on and less when they were off. This created a surge t
hat also broke the auto-squelch on my GTN750. So every time they fired, th
e squelch in my headset broke too.
>> >
>> > This required a new LED design that had a more linear current flow. S
o the current would remain constant even in the off cycles. This addresse
d the auto-squelch on the GTN.
>> >
>> > The newer Garmin Nav/Com=99s don=99t have a squelch knob.
They sense the noise floor and then automatically adjust the squelch to mat
ch the floor. With a constant current draw the floor became constant agai
n and the squelch became functional again.
>> >
>> > Just a word of caution as you go shop LED=99s that flash. My we
re from a very reputable Certified and Experimental lighting provider and no
t cheapo=99s from Napa. It=99s good to ask questions about the c
urrent flow patterns and not just be current flow; especially if your using n
ewer radios with auto squelch.
>> >
>> > Fortunately the provider I used worked with me to make a swap to a newe
r LED version relatively painless and simple.
>> >
>> >
>> >
>> > Sent from my iPhone
>> >
>> >> On Oct 19, 2017, at 6:23 PM, Sean Stephens <sean@stephensville.com> wr
ote:
>> >>
>
>> >>
>> >> 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 hav
e 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 f
or LED landing lights anyways, but have been unable to make them quiet.
>> >>
>> >> -Sean #40303
>> >>
>> >>> Kelly McMullen <mailto:kellym@aviating.com>
>> >>> October 19, 2017 at 4:08 PM
>> >>>
>> >>> The airframe has plenty of surface area to carry any amount of curren
t you will use.
>> >>> Running a separate cable from the battery to firewall central groundi
ng point is a totally wasted effort.
>> >>> Strobes are a bit different animal if you are talking the old capacit
ive 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, w
ith grounding cable to frame , in front of battery box.
>> >>> I have LED nav lights and strobes, all grounded locally, along with V
ans landing lights grounded locally.
>> >>> The central grounding is essential for electronics that amplify noise
s such as intercoms, nav coms etc. It is unnecessary for resistive electrica
l loads, as they don't generate RF noise.
>> >>> My previous aircraft was a Mooney that was built with full zinc chrom
ate primer, mostly non-structural skin, and chrome-moly tube frame, with bat
tery behind baggage compartment. It was just fine with ground wire to airfra
me at battery. Cessna does the same.
>> >>>
>> >>>
>> >>>
>> >>>
>> >>>
>> >>
>> >>
>> >>
>> >>
>> >
>> >
>> >
>> >
>>
>>
>> =========================
>> -List" rel="noreferrer" target="_blank">http://www.matronics.com/Navi
gator?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/contributio
n
>> =========================
>>
>>
>>
>
Message 4
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| Subject: | Re: 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:
>
> 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 its 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@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@gmail.com
>>>> <mailto:civeng123@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@upstate.edu
>>>>> <mailto:ogdenk@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 :)
>>>>>
>>>>>
>>>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>>
>
>
Message 5
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| 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? 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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