Today's Message Index:
----------------------
1. 06:40 AM - Re: Grounding Question On dual Buss Dual Battery Aircraft (user9253)
2. 07:31 AM - Re: Re: Grounding Question On dual Buss Dual Battery Aircraft (Kent or Jackie Ashton)
3. 08:31 AM - Re: Grounding Question On dual Buss Dual Battery Aircraft (Robert L. Nuckolls, III)
4. 08:45 AM - Re: Re: Grounding Question On dual Buss Dual Battery Aircraft (Robert L. Nuckolls, III)
5. 02:55 PM - Re: Grounding Question On dual Buss Dual Battery Aircraft (Trent Heidtke)
6. 03:16 PM - Re: Grounding Question On dual Buss Dual Battery Aircraft (Trent Heidtke)
7. 03:18 PM - Re: Grounding Question On dual Buss Dual Battery Aircraft (Robert L. Nuckolls, III)
Message 1
INDEX | Back to Main INDEX |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Grounding Question On dual Buss Dual Battery Aircraft |
Yes, you are being overly cautious about grounding and might create more serious
problems. Connect the negative terminal of each battery to a common ground
point and connect the negative side of all loads to that common point. Doing
that will not create ground loops.
Consider dual alternators instead of dual batteries, perhaps Z-13/8.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=447588#447588
Message 2
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Grounding Question On dual Buss Dual Battery |
Aircraft
Ditto on avoiding ground loops (a small difference in ground potential at different
ground points that causes a small current loop). In my Cozy, I pulled was
puzzled for years by a squirrelly fuel pressure indicator. The FP sender was
grounded at the engine, FP gauge grounded up front. It is really a problem
with gauging systems that use tiny currents. Probably not so much with big-amp
devices.
-Kent
> On Oct 2, 2015, at 9:38 AM, user9253 <fransew@gmail.com> wrote:
>
>
> Yes, you are being overly cautious about grounding and might create more serious
problems. Connect the negative terminal of each battery to a common ground
point and connect the negative side of all loads to that common point. Doing
that will not create ground loops.
> Consider dual alternators instead of dual batteries, perhaps Z-13/8.
>
> --------
> Joe Gores
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=447588#447588
>
>
>
>
>
>
>
>
>
>
Message 3
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Grounding Question On dual Buss Dual Battery |
Aircraft
At 01:13 AM 10/2/2015, you wrote:
>Hey Trent, my favorite aeroplane!
>
>What power plant?
>
>On 2 October 2015 at 01:22, Trent Heidtke
><<mailto:theidtke@cox.net>theidtke@cox.net> wrote:
>
>Hello everyone, I am new here, building a
>Prescott Pusher, and have a question.=C2 My plane
>is totally electric dependent and so I have been
>following the Aero Connection Diagram Z-19 which
>addresses an outline for a dual battery, single
>alternator, and totally electronic fuel
>injection system.=C2 Additionally, I have
>subscribed 100% to the wiring philosophy whereby
>all powered device grounds go directly to the
>battery running the device instead of the
>massive common ground to frame approach
Please don't do this. See Figure Z-15. ONE
ground for all potential antagonists on the
firewall . . . batteries ground here too.
This ground gets a good connnection to the
welded frame as well. ONE ground for all potential victims on
the panel with a single feed path between panel ground and firewall
ground.
It's okay to use the frame as a ground for
remotely located antagonists . . .
just don't run battery charging currents or starter currents through the
frame.
Had the pleasure of working with Mr. Prescott during my first
tenure at Beech in the Targets Division.
Bob . . .
Message 4
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Grounding Question On dual Buss Dual Battery |
Aircraft
At 09:29 AM 10/2/2015, you wrote:
><kjashton@vnet.net>
>
>Ditto on avoiding ground loops (a small difference in ground
>potential at different ground points that causes a small current
>loop). In my Cozy, I pulled was puzzled for years by a squirrelly
>fuel pressure indicator. The FP sender was grounded at the engine,
>FP gauge grounded up front. It is really a problem with gauging
>systems that use tiny currents. Probably not so much with big-amp devices.
Actually, it was the BIG amp devices that generated
the difference in potential between what was expected
to be same-voltage-grounds.
This was a common problem in early LongEz ships
with no starter and a 30-40a alternator. The builder
RATED his ground return from crankcase to battery(-)
for ALTERNATOR currents . . . so 10A wire at 1 milliohm
per foot x 15ft long x 30A would generate as much as
1/2 volt difference between CRANKCASE ground and
BATTERY ground. Hence, engine grounded 'senders' would
produce strange and variable readings as the alternator
loads varied and only read correctly when the alternator
was off. Problem was still there . . . only much smaller
if the builder added a starter and the crankcase ground
was up-sized to 4 or 2AWG.
Seldom a problem on BIG airplanes. A Beechjet measures
about .001 ohm from stem to stern . . . enough to
experience significant differences in 'ground' potentials
during lighting strikes . . . but seldom an issue for
more mundane current flows circulating between system
grounds. This is why potential victims are grounded at
various locations about the airframe . . . thusly . . .
http://tinyurl.com/odvpk6z
. . . but the ground systems in smaller airplanes and
of course composite aircraft are not so robust. Hence
the need for artful grounding architectures.
Bob . . .
Message 5
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Grounding Question On dual Buss Dual Battery Aircraft |
Hi Bob,
The Prescott Pusher I am building is using a Mazda 20B 3-rotor engine.
I live in the AZ desert so particularly in the summer when going North
to Prescott, Sedona, or Flagstaff I need a bit more than 200 HP/60 inch
prop (original spec=99d items) to get me off the ground. Mazda
3-rotor was about the only weight/HP choice to keep W/B about as close
to original as possible. Still about a year and a half from finishing
but everything has been on it to check fit/function. Just trying to
make sure I am doing wiring right at this point.
Trent
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Bob
Verwey
Sent: Thursday, October 01, 2015 11:14 PM
Subject: Re: AeroElectric-List: Grounding Question On dual Buss Dual
Battery Aircraft
Hey Trent, my favorite aeroplane!
What power plant?
On 2 October 2015 at 01:22, Trent Heidtke <theidtke@cox.net> wrote:
Hello everyone, I am new here, building a Prescott Pusher, and have a
question. My plane is totally electric dependent and so I have been
following the Aero Connection Diagram Z-19 which addresses an outline
for a dual battery, single alternator, and totally electronic fuel
injection system. Additionally, I have subscribed 100% to the wiring
philosophy whereby all powered device grounds go directly to the battery
running the device instead of the massive common ground to frame
approach (I have a metal sub-frame with composite skins over it). As
illustrated in Diagram Z-19, I have set up primary and secondary
batteries and busses with diodes so that #1 fuel pump and ECU have power
all the time from #1 battery. In case of battery failure, flipping
secondary power switch sends power from #2 battery through the diode to
#1 fuel pump and ECU. The challenge is that if I remain pure to the
philosophy of power and ground for any device go to/from the same
battery, #1 fuel pump and ECU are not grounded and so if secondary power
switch is turned on, pump does not work..obviously since it is
not grounded to #2 battery. So I could add a switch to switch grounds
(another level of complexity), or, wire the grounds together at the fuel
pump connection in the back of the plane. Which approach is better? It
is not really addressed in the diagram.that I can interpret
anyway. Maybe I am being overly cautious about the grounding thing but
am trying desperately not to end up with ground loops =93 about
70% wired and so far so good, except for this condition. Any and all
help appreciated..
Thank you
Trent
ist"
target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
tp://forums.matronics.com
_blank">http://www.matronics.com/contribution
--
Best...
Bob Verwey
Message 6
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Grounding Question On dual Buss Dual Battery |
Aircraft
Thank you Bob and everyone that replied to my request for help. It is
very
much appreciated. While I can read and implement schematics done by
people
way more intelligent than I, it is hard sometimes to discern the finer
points that years of experience yields those who have been there and
lived
that. Based on the feedback, I am commencing to rewire the parts that
need
to be changed to comply more with the wisdom shared here.
Regarding the Pusher project, it has been an amazing journey and both
Ole
Sindberg, and Tom Prescott have been immensely helpful (only 2 Prescott
Pushers flying in the US to my knowledge). I hope that first flight
will be
in about 18 months now that I am back full time on the project. At
present
though, the wiring help will ensure success in that department so thank
you
all again.
The next big challenge after wiring is making sure the Mazda 20B
installation goes well. Glad there is an engine thread/forum as well
for
that=85. ;-)
Trent
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
Robert L.
Nuckolls, III
Sent: Friday, October 02, 2015 8:28 AM
Subject: Re: AeroElectric-List: Grounding Question On dual Buss Dual
Battery
Aircraft
At 01:13 AM 10/2/2015, you wrote:
Hey Trent, my favorite aeroplane!
What power plant?
On 2 October 2015 at 01:22, Trent Heidtke <theidtke@cox.net> wrote:
Hello everyone, I am new here, building a Prescott Pusher, and have a
question.=C2 My plane is totally electric dependent and so I have been
following the Aero Connection Diagram Z-19 which addresses an outline
for a
dual battery, single alternator, and totally electronic fuel injection
system.=C2 Additionally, I have subscribed 100% to the wiring
philosophy
whereby all powered device grounds go directly to the battery running
the
device instead of the massive common ground to frame approach
Please don't do this. See Figure Z-15. ONE ground for all potential
antagonists on the
firewall . . . batteries ground here too. This ground gets a good
connnection to the
welded frame as well. ONE ground for all potential victims on
the panel with a single feed path between panel ground and firewall
ground.
It's okay to use the frame as a ground for remotely located
antagonists .
. .
just don't run battery charging currents or starter currents through
the
frame.
Had the pleasure of working with Mr. Prescott during my first
tenure at Beech in the Targets Division.
Bob . . .
Message 7
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Grounding Question On dual Buss Dual Battery |
Aircraft
At 04:53 PM 10/2/2015, you wrote:
>Hi Bob,
>The Prescott Pusher I am building is using a
>Mazda 20B 3-rotor engine.=C2 I live in the AZ
>desert so particularly in the summer when going
>North to Prescott, Sedona, or Flagstaff I need a
>bit more than 200 HP/60 inch prop (original
>spec=99d items) to get me off the
>ground.=C2 Mazda 3-rotor was about the only
>weight/HP choice to keep W/B about as close to
>original as possible.=C2 Still about a year and a
>half from finishing but everything has been on
>it to check fit/function.=C2 Just trying to make
>sure I am doing wiring right at this point.
>Trent
Understand. Have you crafted a load analysis
and prioritized loads under various operating
and failure modes?
Bob . . .
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|