Today's Message Index:
----------------------
1. 08:15 AM - Re: Battery Proximity and mounting (Robert L. Nuckolls, III)
2. 08:54 AM - Terminal N (bcollinsmn)
3. 10:01 AM - Re: Battery Proximity and mounting ()
4. 10:50 AM - Re: First choice alternator decision (Speedy11@aol.com)
5. 11:07 AM - Re: Battery Proximity and mounting (Speedy11@aol.com)
6. 12:09 PM - Re: Battery Proximity and mounting (Robert L. Nuckolls, III)
7. 01:53 PM - Magneto Switch Rating (Vern Little)
8. 02:14 PM - Re: First choice alternator decision (gmcjetpilot@yahoo.com)
9. 02:25 PM - Re: Re: First choice alternator decision (Wade Roe)
10. 02:29 PM - Re: Re: First choice alternator decision (Wade Roe)
11. 02:42 PM - Re: Re: Battery Proximity and mounting (James Quinn)
12. 02:49 PM - Re: Alternator N-Terminal (Robert L. Nuckolls, III)
13. 03:26 PM - Re: Battery Proximity and mounting ()
14. 03:54 PM - Re: Battery Proximity and mounting (Robert L. Nuckolls, III)
15. 04:16 PM - Re: Battery Proximity and mounting (Richard Tasker)
16. 04:39 PM - Re: Re: First choice alternator decision (Robert L. Nuckolls, III)
17. 04:55 PM - Re: Battery Proximity and mounting (Robert L. Nuckolls, III)
18. 06:06 PM - Re: Battery Proximity and mounting ()
19. 07:37 PM - Re: Battery Proximity and mounting (MLWynn@aol.com)
20. 09:03 PM - Re: Dual mags now...one Plasma II plus later (Ed Holyoke)
21. 09:23 PM - Re: Battery Proximity and mounting (Robert L. Nuckolls, III)
22. 09:33 PM - Re: Battery Proximity and mounting (Robert L. Nuckolls, III)
23. 09:34 PM - Re: Dual mags now...one Plasma II plus later (Robert L. Nuckolls, III)
Message 1
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| Subject: | Re: Battery Proximity and mounting |
At 01:14 PM 6/24/2009, you wrote:
>Hi all,
>
>I am building an all-electric RV 8 with dual electronic ignition. I
>plan to use two P680 batteries. As I was sorting out where to put
>them, I had decided to strap them together and put them behind the
>firewall on the right.
>
>A building buddy asked the question, are they okay to be strapped together?
Yes
> Are there any failure modes where one might fail and take out the
> other out at the same time?
No.
>
>I thought I would ask the same question to the list and/or Bob. I
>really like the "change one out every annual" approach described in
>the Aeroelectric book, which is why I am going with two identical
>batteries. The new and improved section on batteries does not
>describe explosion or melt-down as a likely failure of RG batteries
>so I had thought that mounting them together and in the inside of
>the plane would be okay.
>
>In retrospect, I can see that I should have built in the mounting
>system before I riveted on the front bottom skin. As is, I am still
>scratching my head about where exactly to put them and how to
>property secure them to the airframe. I am very open to suggestions.
Are you sure they want to go forward? A lot of
my RV-8 builders had to put them in the tail
for the purposes of satisfying CG limits.
Bob . . .
---------------------------------------
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
---------------------------------------
Message 2
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Hi there. I'm posting this on behalf of a reader of a newsletter I write. Any help
you can give this gentleman would be appreciated:
"Have fitted a Bosch externally regulated alternator which has terminals marked
F, E, and N. I was advised that when the alternator is giving the correct output
there should be 7V potertial at N which I have routed through a relay to
extinguish an LED. When the engine is ticking over at 1000 revs the LED is flickering
on and off but the battery shows 14 volts. Have I got the principle
wrong? what is the purpose of terminal N? "
-- Peter York
--------
Bob Collins
St. Paul, Minn.
RV-7A - Running wires
http://rvbuildershotline.com
Day job: http://minnesota.publicradio.org/collections/special/columns/news_cut/
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=249966#249966
Message 3
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| Subject: | Re: Battery Proximity and mounting |
Bob:
Could you expand further on your answer? Are there any failure modes or
circumstances that would cause an RG battery to fail and drag down the
entire system, including taking the alternator off-line?
Thanks
----- Original Message -----
From: Robert L. Nuckolls, III
To: aeroelectric-list@matronics.com
Sent: Thursday, June 25, 2009 8:14 AM
Subject: Re: AeroElectric-List: Battery Proximity and mounting
At 01:14 PM 6/24/2009, you wrote:
Hi all,
I am building an all-electric RV 8 with dual electronic ignition. I
plan to use two P680 batteries. As I was sorting out where to put them,
I had decided to strap them together and put them behind the firewall on
the right.
A building buddy asked the question, are they okay to be strapped
together?
Yes
Are there any failure modes where one might fail and take out the
other out at the same time?
No.
I thought I would ask the same question to the list and/or Bob. I
really like the "change one out every annual" approach described in the
Aeroelectric book, which is why I am going with two identical batteries.
The new and improved section on batteries does not describe explosion
or melt-down as a likely failure of RG batteries so I had thought that
mounting them together and in the inside of the plane would be okay.
In retrospect, I can see that I should have built in the mounting
system before I riveted on the front bottom skin. As is, I am still
scratching my head about where exactly to put them and how to property
secure them to the airframe. I am very open to suggestions.
Are you sure they want to go forward? A lot of
my RV-8 builders had to put them in the tail
for the purposes of satisfying CG limits.
Bob . . .
---------------------------------------
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
---------------------------------------
Message 4
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| Subject: | Re: First choice alternator decision |
Wade,
I don't know which model of the PP alternator you have, but if you look at
the diagrams for the 60 Amp model
(_http://www.plane-power.com/images/99%20-%209900B.pdf_ (http://www.plane-power.com/images/99%20-%209900B.pdf) )
there is an option for an alternator out warning light. Would that suffice
for a low voltage warning? Actually, should the alternator fail, the
alternator out light should appear before the low voltage warning.
Stan Sutterfield
_www.rv-8a.net_ (http://www.rv-8a.net)
Inspected, Ready to fly
Thank you for the comments. The Plane Power unit has over voltage
protection but no low voltage warning features. My plan would be to
defer that task to the AEC9005-101 (low voltage monitor) that connects
to the main buss per diagram Z-13 AEC. If main buss voltage drops I
don't believe that there would be anything to blame other than the
primary alternator. In this event, you get the bright yellow LV warning
light on the panel and you're shutting down any unnecessary equipment to
see if that will temporarily remedy the issue. My next move would be to
bring up the aux alternator and e-buss...at least I think that would be
the proper protocol.
**************Make your summer sizzle with fast and easy recipes for the
grill. (http://food.aol.com/grilling?ncid=emlcntusfood00000006)
Message 5
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| Subject: | Re: Battery Proximity and mounting |
Michael,
I know other builders have mounted batteries side-by-side with no
problems. Also, they are mounted that way in my golf cart with no problems.
In my
opinion, if you can leave a small airspace between them (say 1/4 to 1/2
inch) then I would do that.
I mounted one P680 in the lower portion of the front baggage and one behind
the aft baggage. I put the aft one there for W&B and it turns out that
worked great because my 8A is within CG limits at all weights and
configurations even with a 3 blade prop and IO-390. Actually I put everything
as far
aft as I could.
Building a bracket for the front battery was challenging. You can see
what I did at _http://www.rv-8a.net/2005.htm_ (http://www.rv-8a.net/2005.htm)
and scroll down to 16 Dec 05 and at _http://www.rv-8a.net/2006.htm_
(http://www.rv-8a.net/2006.htm) - scroll down to 20 Mar 06 and more photos
scattered throughout _http://www.rv-8a.net/2008.htm_
(http://www.rv-8a.net/2008.htm) . I bought the steel jackets for the batteries and made those an
integral part of each bracket.
Regards,
Stan Sutterfield
Inspected, ready to fly
I am building an all-electric RV 8 with dual electronic ignition. I
plan
to use two P680 batteries. As I was sorting out where to put them, I had
decided to strap them together and put them behind the firewall on the
right.
A building buddy asked the question, are they okay to be strapped
together? Are there any failure modes where one might fail and take out
the other
out at the same time?
I thought I would ask the same question to the list and/or Bob. I really
like the "change one out every annual" approach described in the
Aeroelectric book, which is why I am going with two identical batteries.
The
new and
improved section on batteries does not describe explosion or melt-down as
a likely failure of RG batteries so I had thought that mounting them
together and in the inside of the plane would be okay.
In retrospect, I can see that I should have built in the mounting system
before I riveted on the front bottom skin. As is, I am still scratching
my
head about where exactly to put them and how to property secure them to
the
airframe. I am very open to suggestions.
Regards,
Michael Wynn
**************Make your summer sizzle with fast and easy recipes for the
grill. (http://food.aol.com/grilling?ncid=emlcntusfood00000006)
Message 6
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| Subject: | Re: Battery Proximity and mounting |
At 11:58 AM 6/25/2009, you wrote:
>Bob:
>
>Could you expand further on your answer? Are there any failure
>modes or circumstances that would cause an RG battery to fail and
>drag down the entire system, including taking the alternator off-line?
Back in the bad ol' days the lead-acid battery
was prone to various forms of leaking, outgassing,
and cells that shorted when the residue of flaking
plates piled up too high.
RG battery failures are very benign . . . the device
simply stops storing and then giving back electrical
energy. They don't short like the flooded battery.
However, in defense of flooded cell devices: Had we
bothered to maintain them by swapping out an otherwise
working battery when its TESTED capacity dropped
below design goals for battery only operations,
the vast majority of unhappy experiences with this
venerable technology could have been prevented.
The short answer is that there are no failure modes
that cause a battery to take a system down assuming
that it is not abused. Most abuse situations arise
from other system failures such as extended over
voltage conditions:
http://aeroelectric.com/Pictures/Batteries/Odyssey_OV/Odyssey_OV_1.jpg
http://aeroelectric.com/Pictures/Batteries/Internal_Fire/Picture%20001.jpg
Given that you've embraced the new-battery-per-year
philosophy for battery maintenance and assuming you
plan to incorporate active notification of low voltage
and automatic mitigation of over-voltage conditions,
any concerns for battery failure are unwarranted.
Bob . . .
---------------------------------------
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
---------------------------------------
Message 7
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| Subject: | Magneto Switch Rating |
Bob, I am having difficulty finding the electrical specifications
required for toggle switches used as Mag switches.
There is both a withstanding voltage and a current carrying capability
that needs to be met, and I have a need to use miniature toggle switches
rated at 5A/120VAC/28VDC for this function.
Help appreciated.
Thanks, Vern
----- Original Message -----
From: Robert L. Nuckolls, III
To: aeroelectric-list@matronics.com
Sent: Thursday, June 25, 2009 12:06 PM
Subject: Re: AeroElectric-List: Battery Proximity and mounting
At 11:58 AM 6/25/2009, you wrote:
Bob:
Could you expand further on your answer? Are there any failure
modes or circumstances that would cause an RG battery to fail and drag
down the entire system, including taking the alternator off-line?
Back in the bad ol' days the lead-acid battery
was prone to various forms of leaking, outgassing,
and cells that shorted when the residue of flaking
plates piled up too high.
RG battery failures are very benign . . . the device
simply stops storing and then giving back electrical
energy. They don't short like the flooded battery.
However, in defense of flooded cell devices: Had we
bothered to maintain them by swapping out an otherwise
working battery when its TESTED capacity dropped
below design goals for battery only operations,
the vast majority of unhappy experiences with this
venerable technology could have been prevented.
The short answer is that there are no failure modes
that cause a battery to take a system down assuming
that it is not abused. Most abuse situations arise
from other system failures such as extended over
voltage conditions:
http://aeroelectric.com/Pictures/Batteries/Odyssey_OV/Odyssey_OV_1.jpg
http://aeroelectric.com/Pictures/Batteries/Internal_Fire/Picture%20001.jp
g
Given that you've embraced the new-battery-per-year
philosophy for battery maintenance and assuming you
plan to incorporate active notification of low voltage
and automatic mitigation of over-voltage conditions,
any concerns for battery failure are unwarranted.
Bob . . .
---------------------------------------
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
---------------------------------------
Message 8
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| Subject: | Re: First choice alternator decision |
My vote is for Plane Power, for value and design.
The internally regulated model is simpler and has
EXTRA over voltage protection, that has satisfied
even the most knowledgeable expert. If you MUST
have external regulation, Plane Power has that
as well. I have talked to them many times and
Customer service is good. You can buy through
Vans Aircraft (also good customer service).
-
Plane Power now also makes a FAA/PMA voltage
regulator for $169, if you decide to go that way.-
Very nice, compact and no doubt lighter than the
V1200.
-
I have been recommending the Transpo V1200
"Voyager" for years which cost less than $100.
It is made for Ford heavy duty applications.
-
The main complaint of stock internally regulated
alternators in the past,-potential of Over Voltage.
External regulators can have OV as well but they
are easier to-add on EXTRA OV protection. The
Plane Power units eliminates this worry and have
added the same-EXTRA-OV protection that is
preferred by the-experts. So there is no need to
hang another BOX-on the fire wall and run more
wires to an external regulator. That can all be
internal with an-internal regulator making a
cleaner-installation.
-
B&C is more expensive and has no internal
regulator choice. Nothing wrong with B&C fine-
product, good customer care and external
regulation is fine. The voltage- regulator they
sell for $225 is over priced. You can do better
for less than 1/3rd the cost (Transpo V1200).
-
So which one? Can't lose but the tie breaker
is the Plane power.
-
Cheers George
-
-
-
-
>From: "Wade Roe" <wroe1@dbtech.net>
>Subject: AeroElectric-List: First choice alternator decision
>
>Gentleman,
>
>This topic was touched on earlier but I'm still not sure which route is
>best regarding the primary alternator for my RV-7.- I am interested in
>the best quality unit that will also coincide nicely with the AEC system
>designs (particulary Z-13/8).- The options are as follows:
>
>--Plane Power 60A alternator with OV protection and internal
>regulation, or
>
>--B&C L-60 matched up with an LR3C-14.
>
>This will be an all electric IFR plane with one battery and SD-8 aux
>alternator.
>
>Any thoughts or comments would be appreciated.
>
>Thanks!
Wade Roe
EAA 557
Aeronca 7AC flying
RV-7 in process =0A=0A=0A
Message 9
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| Subject: | Re: First choice alternator decision |
Thanks for the insight Stan. It's my opinion that the alternator out
light would in fact suffice. I did not see this as an option on the
unit available from Vans. It's also my understanding that alternators,
especially those manufactured for aviation are very reliable. I'm not
sure what the average life span is. At this point I'm mostly concerned
about having the best, most reliable option.
As we speak, I am doing a load analysis to determine if I even need a 60
amp alternator. Maybe I can get away with a 40 amp and shed 2.5 lb. and
$200.
Wade Roe
SOUTHERN CARBIDE TECHNOLOGIES, INC.
7739 Unity Road M&D Industrial Park
Tuscaloosa, AL 35401
205-248-6700
205-248-6372 fax
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
Speedy11@aol.com
Sent: Thursday, June 25, 2009 12:46 PM
Subject: AeroElectric-List: Re: First choice alternator decision
Wade,
I don't know which model of the PP alternator you have, but if you look
at the diagrams for the 60 Amp model
(http://www.plane-power.com/images/99%20-%209900B.pdf) there is an
option for an alternator out warning light. Would that suffice for a
low voltage warning? Actually, should the alternator fail, the
alternator out light should appear before the low voltage warning.
Stan Sutterfield
www.rv-8a.net
Inspected, Ready to fly
Thank you for the comments. The Plane Power unit has over voltage
protection but no low voltage warning features. My plan would be to
defer that task to the AEC9005-101 (low voltage monitor) that connects
to the main buss per diagram Z-13 AEC. If main buss voltage drops I
don't believe that there would be anything to blame other than the
primary alternator. In this event, you get the bright yellow LV warning
light on the panel and you're shutting down any unnecessary equipment to
see if that will temporarily remedy the issue. My next move would be to
bring up the aux alternator and e-buss...at least I think that would be
the proper protocol.
_____
Make your summer sizzle with fast and easy
<http://food.aol.com/grilling?ncid=emlcntusfood00000006> recipes for
the grill.
Message 10
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| Subject: | Re: First choice alternator decision |
Thanks George for the comments and insight. I'll investigate the V1200.
Wade Roe
EAA 557
Aeronca 7AC flying
RV-7 in process
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
gmcjetpilot@yahoo.com
Sent: Thursday, June 25, 2009 4:04 PM
Subject: AeroElectric-List: Re: First choice alternator decision
My vote is for Plane Power, for value and design.
The internally regulated model is simpler and has
EXTRA over voltage protection, that has satisfied
even the most knowledgeable expert. If you MUST
have external regulation, Plane Power has that
as well. I have talked to them many times and
Customer service is good. You can buy through
Vans Aircraft (also good customer service).
Plane Power now also makes a FAA/PMA voltage
regulator for $169, if you decide to go that way.
Very nice, compact and no doubt lighter than the
V1200.
I have been recommending the Transpo V1200
"Voyager" for years which cost less than $100.
It is made for Ford heavy duty applications.
The main complaint of stock internally regulated
alternators in the past, potential of Over Voltage.
External regulators can have OV as well but they
are easier to add on EXTRA OV protection. The
Plane Power units eliminates this worry and have
added the same EXTRA OV protection that is
preferred by the experts. So there is no need to
hang another BOX on the fire wall and run more
wires to an external regulator. That can all be
internal with an internal regulator making a
cleaner installation.
B&C is more expensive and has no internal
regulator choice. Nothing wrong with B&C fine
product, good customer care and external
regulation is fine. The voltage regulator they
sell for $225 is over priced. You can do better
for less than 1/3rd the cost (Transpo V1200).
So which one? Can't lose but the tie breaker
is the Plane power.
Cheers George
>From: "Wade Roe" <
<http://us.mc431.mail.yahoo.com/mc/compose?to=wroe1@dbtech.net>
wroe1@dbtech.net>
>Subject: AeroElectric-List: First choice alternator decision
>
>Gentleman,
>
>This topic was touched on earlier but I'm still not sure which route is
>best regarding the primary alternator for my RV-7. I am interested in
>the best quality unit that will also coincide nicely with the AEC
system
>designs (particulary Z-13/8). The options are as follows:
>
>--Plane Power 60A alternator with OV protection and internal
>regulation, or
>
>--B&C L-60 matched up with an LR3C-14.
>
>This will be an all electric IFR plane with one battery and SD-8 aux
>alternator.
>
>Any thoughts or comments would be appreciated.
>
>Thanks!
Wade Roe
EAA 557
Aeronca 7AC flying
RV-7 in process
Message 11
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| Subject: | Re: Battery Proximity and mounting |
Bob,One of the links below (http://www.rv-8a.net/2005.htm) shows the Tempo
marine or race car type battery switches being used in lieu of battery
contractors. This seems like a very good idea, i.e. less cost, less weight
and almost absolute reliability (assuming you don't loss the keys). Your
comments?
On Thu, Jun 25, 2009 at 13:02, <Speedy11@aol.com> wrote:
> Michael,
> I know other builders have mounted batteries side-by-side with no
> problems. Also, they are mounted that way in my golf cart with no
> problems. In my opinion, if you can leave a small airspace between them
> (say 1/4 to 1/2 inch) then I would do that.
> I mounted one P680 in the lower portion of the front baggage and one behind
> the aft baggage. I put the aft one there for W&B and it turns out that
> worked great because my 8A is within CG limits at all weights and
> configurations even with a 3 blade prop and IO-390. Actually I put
> everything as far aft as I could.
> Building a bracket for the front battery was challenging. You can see what
> I did at http://www.rv-8a.net/2005.htm and scroll down to 16 Dec 05 and at
> http://www.rv-8a.net/2006.htm - scroll down to 20 Mar 06 and more photos
> scattered throughout http://www.rv-8a.net/2008.htm. I bought the steel
> jackets for the batteries and made those an integral part of each bracket.
> Regards,
> Stan Sutterfield
> Inspected, ready to fly
>
>
> I am building an all-electric RV 8 with dual electronic ignition. I plan
> to use two P680 batteries. As I was sorting out where to put them, I had
> decided to strap them together and put them behind the firewall on the
> right.
>
> A building buddy asked the question, are they okay to be strapped
> together? Are there any failure modes where one might fail and take out
> the other
>
> out at the same time?
>
> I thought I would ask the same question to the list and/or Bob. I really
> like the "change one out every annual" approach described in the
> Aeroelectric book, which is why I am going with two identical batteries.
> The
> new and
> improved section on batteries does not describe explosion or melt-down as
> a likely failure of RG batteries so I had thought that mounting them
> together and in the inside of the plane would be okay.
>
> In retrospect, I can see that I should have built in the mounting system
> before I riveted on the front bottom skin. As is, I am still scratching
> my
> head about where exactly to put them and how to property secure them to
> the
> airframe. I am very open to suggestions.
>
> Regards,
>
> Michael Wynn
>
>
> ------------------------------
> Make your summer sizzle with fast and easy recipes<http://food.aol.com/grilling?ncid=emlcntusfood00000006>for the grill.
>
> *
>
> *
>
>
Message 12
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| Subject: | Re: Alternator N-Terminal |
At 10:49 AM 6/25/2009, you wrote:
><bob@rvbuildershotline.com>
>
>Hi there. I'm posting this on behalf of a reader of a newsletter I
>write. Any help you can give this gentleman would be appreciated:
>
>"Have fitted a Bosch externally regulated alternator which has
>terminals marked F, E, and N. I was advised that when the
>alternator is giving the correct output there should be 7V
>potertial at N which I have routed through a relay to extinguish an
>LED. When the engine is ticking over at 1000 revs the LED is
>flickering on and off but the battery shows 14 volts. Have I got the
>principle wrong? what is the purpose of terminal N? "
To understand the answer to your question we need to
go back about 42 years to when the first alternators
(Ford derivatives) were being bolted to airplanes
for the first time. The regulators were stock
automotive, 2-relay, electro-mechanical devices
shown in this figure . . .
http://www.aeroelectric.com/Pictures/Regulators/Legacy_EM_Regulator_(Ford).pdf
Terminal N is the center tap on a "Y-wound" stator.
Yes, it has an output nominally 1/2 that of the
B terminal. It was originally used to sense the fact
that the alternator was being turned by an engine and
was ready to produce power to the vehicle's systems.
A field control relay was powered from the N terminal
as shown in the attendant drawing. If the altenrator
control switch was open, field excitation through the
alternator fail light was zero. . . OR . . . if the
alternator was not turning, then N-terminal voltage
was zero.
If the alternator is turning and the control switch
is closed, then a small current (100 mA or so) places
a small excitation current on the alternator's field
terminal through the normally closed contacts of the
v-reg relay. This causes the stator windings to produce
voltage that is essentially unloaded (open circuit)
until high enough to begin to conduct the diodes and
deliver energy to the system. In this very lightly
loaded state, the N-terminal voltage rises and energizes
the field control relay.
When the field relay closes, full bus voltage is
available through a low impedance source and causes
the alternator to wake up and power the ship's
systems.
If the engine is stopped, or a belt breaks, N-terminal
volts goes to zero. Field control relay drops out
removing a short across the ALT WARN lamp causing it
to illuminate assuming that the control switch is
still closed.
This opens the high current loop for supplying
alternator field current thus stopping internal
generation of heat in the alternator and depleting
the battery with no-value-added load of field
current.
I don't recall that Cessna ever used the N-terminal
or field control relay for this purpose. We chose
to apply bus voltage directly to the regulator's
"S" terminal through the alternator control switch.
In later years, the OV control module was placed
in series with the field control relay as shown
in . . .
http://www.aeroelectric.com/Pictures/Schematics/Cessna_OVModule.gif
Years later in the employ of Electro-Mech, I
was designer of some rather crude voltage level
sensors that watched the N-terminal voltage with
the idea that it was good place to detect an
alternator failure. We supplied these modules
to Cessna and Beech. After working this industry
for several years, I discovered that there were
failure modes that would cripple the alternator's
ability to power the system that COULD NOT BE
DETECTED by watching the N-terminal.
I recommended and developed a low-voltage
warning module that was adopted by Beech. I
don't recall if we ever sold any to Cessna.
The short answer to your question: I recommend
that you ignore the N-terminal of your alternator
and install some form of active notification of
low voltage set up to warn for any condition
where bus voltage drops below 13.0 volts. This
is one of several solutions to the low voltage
warning task.
http://www.aeroelectric.com/DIY/LV_Warn_Fab_and_Install.pdf
Bob . . .
Message 13
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| Subject: | Re: Battery Proximity and mounting |
Bob:
Thanks, that's good to hear. If I could take this one step further for
the RG batteries:
If there is a zero probability of battery failure (assuming it's not
abused and maintenance benefits aside), strictly from the battery's
contribution to system reliability, is there is any benefit gained from
a dual battery as compared to single battery installation?
Thanks
----- Original Message -----
From: Robert L. Nuckolls, III
To: aeroelectric-list@matronics.com
Sent: Thursday, June 25, 2009 12:06 PM
Subject: Re: AeroElectric-List: Battery Proximity and mounting
At 11:58 AM 6/25/2009, you wrote:
Bob:
Could you expand further on your answer? Are there any failure
modes or circumstances that would cause an RG battery to fail and drag
down the entire system, including taking the alternator off-line?
Back in the bad ol' days the lead-acid battery
was prone to various forms of leaking, outgassing,
and cells that shorted when the residue of flaking
plates piled up too high.
RG battery failures are very benign . . . the device
simply stops storing and then giving back electrical
energy. They don't short like the flooded battery.
However, in defense of flooded cell devices: Had we
bothered to maintain them by swapping out an otherwise
working battery when its TESTED capacity dropped
below design goals for battery only operations,
the vast majority of unhappy experiences with this
venerable technology could have been prevented.
The short answer is that there are no failure modes
that cause a battery to take a system down assuming
that it is not abused. Most abuse situations arise
from other system failures such as extended over
voltage conditions:
http://aeroelectric.com/Pictures/Batteries/Odyssey_OV/Odyssey_OV_1.jpg
http://aeroelectric.com/Pictures/Batteries/Internal_Fire/Picture%20001.jp
g
Given that you've embraced the new-battery-per-year
philosophy for battery maintenance and assuming you
plan to incorporate active notification of low voltage
and automatic mitigation of over-voltage conditions,
any concerns for battery failure are unwarranted.
Bob . . .
---------------------------------------
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
---------------------------------------
Message 14
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| Subject: | Re: Battery Proximity and mounting |
Re: Battery Proximity and mounting
From: James Quinn <jquinn3@gmail.com>
Bob,
One of the links below
(<http://www.rv-8a.net/2005.htm>http://www.rv-8a.net/2005.htm) shows
the Tempo marine or race car type battery switches being used in lieu
of battery contractors. This seems like a very good idea, i.e. less
cost, less weight and almost absolute reliability (assuming you don't
loss the keys). Your comments?
A number of airplanes (including type
certified) have used battery switches
in lieu of contactors. A TriPacer I used
to fly had manual battery switch AND a
high current, manually operated starter
switch. No contactors at all.
So there's nothing particularly unusual
about the idea. A decision to substitute
manual switches for contactors needs to meet
design goals for convenient accessibility
under all flight conditions: Both normal
and those which anticipate un-intended
arrivals with the earth. Recall that the
battery switch is designed make the
ship's wiring max-cold when off.
Bob . . .
---------------------------------------
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
---------------------------------------
Message 15
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| Subject: | Re: Battery Proximity and mounting |
I think if you read the response, he is not saying that there is a zero
probability of battery failure, just essentially a zero probability of a
failure that will also bring down the whole system.
I.e. the battery could fail so that it no longer can supply current, but
this failure would have no effect on the rest of the system if you still
had a second battery. Obviously, if you have only one battery and it
stops supplying current that you need then you have a problem.
Dick
Flagstone@cox.net wrote:
> Bob:
>
> Thanks, that's good to hear. If I could take this one step further
> for the RG batteries:
>
> If there is a zero probability of battery failure (assuming it's not
> abused and maintenance benefits aside), strictly from the battery's
> contribution to system reliability, is there is any benefit gained
> from a dual battery as compared to single battery installation?
>
> Thanks
>
>
> ----- Original Message -----
> *From:* Robert L. Nuckolls, III
> <mailto:nuckolls.bob@aeroelectric.com>
> *To:* aeroelectric-list@matronics.com
> <mailto:aeroelectric-list@matronics.com>
> *Sent:* Thursday, June 25, 2009 12:06 PM
> *Subject:* Re: AeroElectric-List: Battery Proximity and mounting
>
> At 11:58 AM 6/25/2009, you wrote:
>> Bob:
>>
>> Could you expand further on your answer? Are there any failure
>> modes or circumstances that would cause an RG battery to fail and
>> drag down the entire system, including taking the alternator
>> off-line?
>
> Back in the bad ol' days the lead-acid battery
> was prone to various forms of leaking, outgassing,
> and cells that shorted when the residue of flaking
> plates piled up too high.
>
> RG battery failures are very benign . . . the device
> simply stops storing and then giving back electrical
> energy. They don't short like the flooded battery.
> However, in defense of flooded cell devices: Had we
> bothered to maintain them by swapping out an otherwise
> working battery when its TESTED capacity dropped
> below design goals for battery only operations,
> the vast majority of unhappy experiences with this
> venerable technology could have been prevented.
>
> The short answer is that there are no failure modes
> that cause a battery to take a system down assuming
> that it is not abused. Most abuse situations arise
> from other system failures such as extended over
> voltage conditions:
>
> http://aeroelectric.com/Pictures/Batteries/Odyssey_OV/Odyssey_OV_1.jpg
>
>
> http://aeroelectric.com/Pictures/Batteries/Internal_Fire/Picture%20001.jpg
>
>
> Given that you've embraced the new-battery-per-year
> philosophy for battery maintenance and assuming you
> plan to incorporate active notification of low voltage
> and automatic mitigation of over-voltage conditions,
> any concerns for battery failure are unwarranted.
>
> Bob . . .
>
> ---------------------------------------
> ( . . . a long habit of not thinking )
> ( a thing wrong, gives it a superficial )
> ( appearance of being right . . . )
> ( )
> ( -Thomas Paine 1776- )
> ---------------------------------------
>
> *
>
> href="http://www.matronics.com/Navigator?AeroElectric-List">http://www.matronics.com/Navigator?AeroElectric-List
> href="http://forums.matronics.com">http://forums.matronics.com
> href="http://www.matronics.com/contribution">http://www.matronics.com/c
> *
>
> *
>
>
> *
Message 16
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| Subject: | Re: First choice alternator decision |
From: "Wade Roe" <wroe1@dbtech.net>
Subject: RE: AeroElectric-List: Re: First choice alternator decision
Thanks for the insight Stan. It's my opinion that the alternator out
light would in fact suffice. I did not see this as an option on the
unit available from Vans. It's also my understanding that
alternators, especially those manufactured for aviation are very
reliable. I'm not sure what the average life span is. At this point
I'm mostly concerned about having the best, most reliable option.
Your electrical SYSTEM can offer satisfactory
'reliability' in spite of individual components
failure. This is the cornerstone of failure
tolerant design. It's far more useful to design
and fabricate with a foregone conclusion that
any part can and will at some time fail in flight.
Further, price of a component is not necessarily
directly related to expected service life. Based
on anecdotal observation, most failures of an
alternator installation are unrelated to the
physical alternator. The only mechanical wearing
parts of an alternator are bearings-and-
brushes-on-slip-rings. There are thermal service-life-
limiting stresses that influence diodes, integrated
circuits, bond-wire joints, etc. Generally speaking,
it's not difficult to fabricate a belt driven
alternator with a service life that equals that of
the engine. But poor choice of attach hardware,
wiring supports can be equally crippling of
alternator performance.
The purpose of this little dissertation is to suggest
that much of what's reported as an "alternator
problem" has nothing to do with the design or
fabricating processes in the alternator itself.
Given that absolute "quality" in terms of service
life cannot be absolutely predicted, I'll suggest
it's more useful to use what ever combination of
products is most attractive for price, weight,
ease of installation while mitigating reliability
worries with crafty failure tolerant design.
Understand that the "alternator out" light feature
of an internally regulated alternator is operated
from the same slab of silicon as the voltage
regulator. See:
http://aeroelectric.com/Mfgr_Data/Semiconductors/MC33092A_Block_Diagram.pdf
This drawing is a somewhat dated (but I think exemplar)
architecture for an internally regulated alternator.
Note that the lamp circuit is driven from the
integrated circuit chip. The ability of this
lamp to annunciate ALL forms of alternator failure
is not known. Further, since the warning functions
share hardware and space with controlling functions,
it does not conform with design goals for most
aircraft systems that call for separation of
control and failure monitoring/annunciation.
Observance of those design goals calls for active
notification of low voltage that is independent
of the alternator and it's regulator. This concept
is common to many TC aircraft and is suggested by
illustration throughout the Z-figures.
Bob . . .
Message 17
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| Subject: | Re: Battery Proximity and mounting |
At 05:19 PM 6/25/2009, you wrote:
Bob:
Thanks, that's good to hear. If I could take this one step further
for the RG batteries:
If there is a zero probability of battery failure (assuming it's not
abused and maintenance benefits aside), strictly from the battery's
contribution to system reliability, is there is any benefit gained
from a dual battery as compared to single battery installation?
The reasons for dual batteries are few and specific.
Z-14 calls for dual batteries because you have dual
systems. If you have one alternator and an electrically
dependent engine, then Z-19 suggests a means by which
an alternator failure can be responded to by having
engine and instruments supported by separate batteries
while operating in the endurance mode.
We've also discussed appliances not designed to live
in the real world of airplanes and require support
of a battery that is independent of the cranking
battery.
I neglected ask why you were considering two batteries.
Bob . . .
---------------------------------------
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
---------------------------------------
Message 18
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| Subject: | Re: Battery Proximity and mounting |
Bob:
Are any of those reasons for Z-14 as a result of the design and performance
of the RG batteries by themselves, or are they the result of other potential
failures extraneous to the batteries? If any of the reasons are a result of
the batteries, what are they and what are the probabilities of them
happening?
Another group member stated that "the battery could fail so that it can no
longer supply current". He may be correct that I misunderstood your
previous answer. I would consider that within the scope of my previous
question, in that it seems to me that if a battery were to suddenly be
unable to supply current, it would be the result of some sort of internal
failure. If that in fact can happen, what are the circumstances that would
cause that, and what are the probabilities of it happening?
I intend to use to use two batteries for the maintenance benefits you
outline in your book and for the additional cranking power.
Right now I'm just trying to get a clear understanding of the RG battery's
reliability and performance limitations.
Thanks
----- Original Message -----
From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
Sent: Thursday, June 25, 2009 4:51 PM
Subject: Re: AeroElectric-List: Battery Proximity and mounting
> <nuckolls.bob@aeroelectric.com>
>
>
> At 05:19 PM 6/25/2009, you wrote:
> Bob:
>
> Thanks, that's good to hear. If I could take this one step further for
> the RG batteries:
>
> If there is a zero probability of battery failure (assuming it's not
> abused and maintenance benefits aside), strictly from the battery's
> contribution to system reliability, is there is any benefit gained from a
> dual battery as compared to single battery installation?
>
> The reasons for dual batteries are few and specific.
> Z-14 calls for dual batteries because you have dual
> systems. If you have one alternator and an electrically
> dependent engine, then Z-19 suggests a means by which
> an alternator failure can be responded to by having
> engine and instruments supported by separate batteries
> while operating in the endurance mode.
>
> We've also discussed appliances not designed to live
> in the real world of airplanes and require support
> of a battery that is independent of the cranking
> battery.
>
> I neglected ask why you were considering two batteries.
>
> Bob . . .
>
> ---------------------------------------
> ( . . . a long habit of not thinking )
> ( a thing wrong, gives it a superficial )
> ( appearance of being right . . . )
> ( )
> ( -Thomas Paine 1776- )
> ---------------------------------------
>
>
>
Message 19
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| Subject: | Re: Battery Proximity and mounting |
First off, thank you all for the replies and the group think.
My main reason for two batteries is the dual electronic ignition. Claus
at Lightspeed strongly suggests a back-up battery if you are completely
electrically dependent. I have read the Aeroelectric book through several
times. I suppose that I may be in overkill mode, but I have a main and back-up
alternator (B&C 60 Amp and 20 amp). While I have not yet done the wiring
or really completed the drawings, I was thinking strongly of a Vertical
Power VP 100 around a system that is basically a Z12 with a second battery.
The VP will not really support a Z14 style architecture.
If I am going to have a second battery per the ignition system's
manufacturers recommendation, it seems reasonable to use identical batteries and
plan a yearly rotation. Is this complete overkill? Adding a cross feed
connector gives you the opportunity to have additional cranking power in case
of
starting difficulties.
Thoughts?
Michael Wynn
RV 8
San Ramon
In a message dated 6/25/2009 4:56:55 P.M. Pacific Daylight Time,
nuckolls.bob@aeroelectric.com writes:
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<nuckolls.bob@aeroelectric.com>
At 05:19 PM 6/25/2009, you wrote:
Bob:
Thanks, that's good to hear. If I could take this one step further
for the RG batteries:
If there is a zero probability of battery failure (assuming it's not
abused and maintenance benefits aside), strictly from the battery's
contribution to system reliability, is there is any benefit gained
from a dual battery as compared to single battery installation?
The reasons for dual batteries are few and specific.
Z-14 calls for dual batteries because you have dual
systems. If you have one alternator and an electrically
dependent engine, then Z-19 suggests a means by which
an alternator failure can be responded to by having
engine and instruments supported by separate batteries
while operating in the endurance mode.
We've also discussed appliances not designed to live
in the real world of airplanes and require support
of a battery that is independent of the cranking
battery.
I neglected ask why you were considering two batteries.
Bob . . .
---------------------------------------
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
---------------------------------------
**************Shop Popular Dell Laptops now starting at $349!
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Message 20
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| Subject: | Re: Dual mags now...one Plasma II plus later |
Yup, but you'll need to turn one of the switches over when you want to
use it to switch the ei. The mag switch closes to turn the mag off, but
the ei switch will close to turn on. You want the "up" position to be on.
Pax,
Ed Holyoke
Robert L. Nuckolls, III wrote:
> <nuckolls.bob@aeroelectric.com>
>
> At 08:58 AM 6/23/2009, you wrote:
>>
>> My plan is to fly off several hours in the RV-7 using two Slick mags
>> before transitioning over to a one mag and Plasma II plus system. With
>> this in mind, what is the best way to spec-out and set-up the ignition
>> switches? I am referencing Z-13/8 AEC as the basis for my design. The
>> Z-13 diagram shows an s700-1-3 and a s700-2-10. Perhaps a s700-2-50
>> would make more sense.
>
> A pair of S700-1-3 switches will do fine for both the pair
> of mags and for the final configuration.
>
>
> Bob . . .
>
> ---------------------------------------
> ( . . . a long habit of not thinking )
> ( a thing wrong, gives it a superficial )
> ( appearance of being right . . . )
> ( )
> ( -Thomas Paine 1776- )
> ---------------------------------------
>
>
Message 21
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| Subject: | Re: Battery Proximity and mounting |
At 07:59 PM 6/25/2009, you wrote:
>
>Bob:
>
>Are any of those reasons for Z-14 as a result of the design and
>performance of the RG batteries by themselves, or are they the
>result of other potential failures extraneous to the batteries? If
>any of the reasons are a result of the batteries, what are they and
>what are the probabilities of them happening?
Z-14 is the "mother of all electrical systems" intended
to address the design goals for probably less than 1%
of the OBAM aircraft fleet. This would be the Lancair
or Glasair with fully redundant IFR panels on both
pilot seats wherein the aircraft's missions often
include two rated pilots and a high percentage of
flight in IMC.
Batteries swapped out when their battery-only endurance
capabilities drop below 2+ hours are still cranking
and engine nicely . . . and a battery this capable is
exceedingly unlikely to go south on you en route to
aunt Martha's.
For my purposes and for the purposes of the majority
of the OBAM fleet, Z-13/8 with a battery maintenance
program offers SYSTEM reliability that is head and
shoulders above the majority of TC fleet up to and
including some twin turbine powered aircraft.
>Another group member stated that "the battery could fail so that it
>can no longer supply current". He may be correct that I
>misunderstood your previous answer. I would consider that within
>the scope of my previous question, in that it seems to me that if a
>battery were to suddenly be unable to supply current, it would be
>the result of some sort of internal failure. If that in fact can
>happen, what are the circumstances that would cause that, and what
>are the probabilities of it happening?
Can't put a number on "probability" and if I
could, it probably wouldn't be significant to
you. The point about battery technology and
service life is that hundreds of thousands of
airplanes have launched into IFR with a single generator
and single flooded battery with a high probability
of a now-sweat termination of the flight. The
demonstrated level of system reliability was such
that many pilots exploited the capability with
little concern for system failure. The majority
of accidents were (and still are) seeded by
poor judgement and/or conditions beyond
control of the pilot that were not related
to system reliability.
Now we can easily install two engine driven
power sources to charge a well maintained,
very user-friendly RG battery. A combination
that reduces risks of power starvation to
still lower numbers.
If you're willing to jump in a rented C182
and launch into the grey with equipment
certificated 30 years ago, then getting into
your RV fitted with Z-13/8 + RG battery has to
be more comfortable yet. Bottom line is that with
either airplane, your risk for experiencing
an unhappy day in the cockpit has more to
do with what's between your ears than with
what's under the cowl.
>I intend to use to use two batteries for the maintenance benefits
>you outline in your book and for the additional cranking power.
Dual batteries are indicated only for those special
conditions I cited earlier. If you don't have those
configurations . . . dual batteries are only a cost,
volume and weight burden on your project.
>Right now I'm just trying to get a clear understanding of the RG
>battery's reliability and performance limitations.
If all you want is more cranking power, install ONE
bigger battery. But cranking power of RG batteries
is so much better than their flooded counterparts
that we're installing systems like Z-13/8 with a small
fraction of the hardware weight in a 1975 Cessna
182. Unless you have operational features that
encourage dual batteries, please consider installing
a single 17 to 18 a.h. RG battery. You can always
up-size later. But consider leaving 16 pounds of
hardware on the ground until you KNOW you need it.
16 extra pounds of baggage or fuel is USEFUL . . . 16
unnecessary pounds of battery is . . . well . . .
you know.
I'm betting you'll never need it.
Bob . . .
Message 22
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| Subject: | Re: Battery Proximity and mounting |
At 09:29 PM 6/25/2009, you wrote:
First off, thank you all for the replies and the group think.
My main reason for two batteries is the dual electronic
ignition. Claus at Lightspeed strongly suggests a back-up battery if
you are completely electrically dependent. I have read the
Aeroelectric book through several times. I suppose that I may be in
overkill mode, but I have a main and back-up alternator (B&C 60 Amp
and 20 amp). While I have not yet done the wiring or really
completed the drawings, I was thinking strongly of a Vertical Power
VP 100 around a system that is basically a Z12 with a second
battery. The VP will not really support a Z14 style architecture.
If I am going to have a second battery per the ignition system's
manufacturers recommendation, it seems reasonable to use identical
batteries and plan a yearly rotation. Is this complete
overkill? Adding a cross feed connector gives you the opportunity to
have additional cranking power in case of starting difficulties.
Don't know about "complete" overkill . . . but
it's in the 90th percentile.
Z-13/8 and one battery with EACH ignition enjoying
it's own fuse on the battery bus is a very
rational approach. Keep in mind that your
engine will run fine on ONE ignition. In fact,
If you find yourself running from the e-bus on
either Z-11 or Z-13/8, I'd shut off one of the
two ignition systems and use the power for something
more useful.
I'm working an accident case right now where the
owner/pilot got wrapped around the "reliability
axle" and designed a dual ignition power distribution
system guaranteed to fail both ignitions . . . and it did.
Save your money for an extra GPS or perhaps dual
wing-levelers. Z-13/8 will keep them all humming
at much less cost and weight in your airplane . . .
and easier to install too.
Better yet, the extra dollars buys stuff that
ADDS value to the airplane.
Bob . . .
Message 23
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| Subject: | Re: Dual mags now...one Plasma II plus later |
At 11:58 PM 6/25/2009, you wrote:
>
>Yup, but you'll need to turn one of the switches over when you want
>to use it to switch the ei. The mag switch closes to turn the mag
>off, but the ei switch will close to turn on. You want the "up"
>position to be on.
No, the 1-3 switches are single pole, two position switches.
They function for either breaking power to an electronic
ignition -OR- grounding a magneto by simply moving a wire
to the opposite terminal.
Bob . . .
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( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
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