Today's Message Index:
----------------------
1. 12:12 AM - Re: Rear battery earthing structure (Neil Parkinson)
2. 06:39 AM - Re: Re: Question: can these wires be put in one wire bundle? (FLYaDIVE)
3. 09:04 AM - Re: Rear battery earthing structure (Robert L. Nuckolls, III)
4. 09:47 AM - Re: Re: Question: can these wires be put in one wire bundle? (Robert L. Nuckolls, III)
5. 10:20 AM - Re: Re: Question: can these wires be put in one wire bundle? (Robert L. Nuckolls, III)
6. 01:19 PM - Re: Rear battery earthing structure (Bill Watson)
7. 06:10 PM - A brown-out alternative? (Robert L. Nuckolls, III)
8. 06:19 PM - B lead circuit breaker (Ron Burnett)
9. 06:48 PM - Re: A brown-out alternative? (Art Zemon)
10. 06:50 PM - Re: A brown-out alternative? (Roger)
11. 06:51 PM - Re: B lead circuit breaker (Art Zemon)
12. 07:11 PM - Re: A brown-out alternative? (Charlie England)
13. 07:26 PM - Re: B lead circuit breaker (Ron Burnett)
14. 08:37 PM - Re: B lead circuit breaker (Robert L. Nuckolls, III)
15. 10:55 PM - Re: A brown-out alternative? (Eric Page)
Message 1
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| Subject: | Re: Rear battery earthing structure |
Thanks Bob.
Yes in the rear I was planning on installing the remote boxes for the transp
onder , com , etc.
So yes Audio and digital signals going back and forth ? How that effect the e
arth situation ?
Neil
> On 8 Oct 2018, at 00:22, Robert L. Nuckolls, III <nuckolls.bob@aeroelectri
c.com> wrote:
>
> At 05:46 PM 10/7/2018, you wrote:
enworld.com>
>>
>> Hi Everybody.
>>
>> I=99m building an RV8 with a rear battery location.
>>
>> Can I please have some advice on the earthing structure . Can I just eart
h the battery to the structure in the rear , then take it the common earth a
t the panel ? Or is it worth running some asw2 cable to earth the panel , or
the engine ??
>
> Ground battery locally
>
> http://aeroelectric.com/Pictures/Batteries/Battery_Install_OBrien_3.jpg
> http://aeroelectric.com/Pictures/Grounding/Local_Battery_Grounds_1.jpg
>
> Install ground bus on firewall.
>
> http://aeroelectric.com/Pictures/Grounding/Forest_of_Tabs_Ground_Kit.pdf
> http://aeroelectric.com/Pictures/Grounding/gnd_bus.jpg
>
>
> Run braided-flat-wire
> from crankcase to firewall ground stud.
>
> http://aeroelectric.com/Pictures/Grounding/Braided%20Copper%20Bond%20Strap
s.jpg
>
>
>
>> I will have some rear avionics equipment , should I run the earth from th
e panel to these ? Or just tap of the structure locally ?
>
> What kind of avionics? Anything with audio or digital
> signal leads?
>
> Bob . . .
Message 2
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| Subject: | Re: Question: can these wires be put in one wire |
bundle?
Rick:
You did right by mounting the Magnetometer in the tail.
As I said I have installed four G5 systems. Of course I tried the wing as
my first location on my first job.
It was difficult to run the wires and there were other problems:
a> If you go far out on the wing to get away from the noise of the engine
compartment you become too close to the wing tip strobe.
b> And just the opposite when you move the Magnetometer closer to the
engine compartment to get away from the noise of the wing tip strobe, you
get too close to the engine compartment noise.
Ya can't win for loosing!
On Sun, Oct 7, 2018 at 9:47 PM Rick Beebe <rick@beebe.org> wrote:
> On 10/7/2018 2:41 PM, FLYaDIVE wrote:
>
> Is the G5 the victim or
>
>> the antagonist?
>>
> Barry - It is the VICTIM, as the G5 has a Noise Testing program built into
> them.
> The big issue of noise, is because it has a remote mounted Magnetometer.
>
> But I don't think it's fair to say the G5 is susceptible to noise.
>
Barry - You DON'T! It is totally fair to call a spade a spade. They are
very susceptible to noise. So much so that Garmin installed a Noise
Detecting Program. How can you not say they ARE susceptible? You even
make that statement ;-p
> By their nature, magnetometers are sensitive beasts.
>
> --Rick
>
Barry - So, you did Very Good mounting it in the tail. It was probably
even easier to install and will be easier to access to work on - Well, I
don't know your plane but it is in the planes I have installed them in.
Rick, did you notice there is a wire length [sort of] limit for the
Magnetometer? They want you to keep it 15 ft or less. That was a hard
STRETCH of the wire situation.
There is another issue that has snuck its head into our 'modern' aviation
world. Things Change - Way Back in Bob N.'s day of King Air and simple
bundles of wires with ALL cables bundled together is No Longer. We have
new items entering the market place every day and many produce noise. We
have to do what ever we can to reduce and eliminate all sorts of noise.
Here on this list we spoke about the modern noise from LED's. It's not
going away.
Simple procedures like twisting power wires may help. And, if it does not,
it ain't gaun-a hurt! I use Red and Black wires constantly to show the
power wires, it just makes things easier. I also use Blue, Yellow, Green
and White. :-D No Chartreuse! It clashes with my eyes.
Barry
Message 3
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| Subject: | Re: Rear battery earthing structure |
At 02:09 AM 10/8/2018, you wrote:
>Thanks Bob.
>
>Yes in the rear I was planning on installing the remote boxes for
>the transponder , com , etc.
>
>So yes Audio and digital signals going back and forth ? How that
>effect the earth situation ?
>
>Neil
Follow the wiring diagrams in the installation
manuals.
Remotely mounted black-boxes have been
around for a VERY LONG TIME . . . WWII radios
were almost always remotely mounted . . . that
vacuum tube stuff just wouldn't fit into an
already tight cockpit.
Signal and power management for such installations
were well understood and accounted for in the
installation instructions.
Having said that, it is not difficult to design
such systems to be goof-proof . . . difficult
to even deliberately cause a noise issue.
The vast majority of noise problems I've encountered
in light aircraft were in the audio system with
improper management of grounds to microphones and
headset jacks.
Bob . . .
Message 4
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| Subject: | Re: Question: can these wires be put in one |
wire bundle?
>
>There is another issue that has snuck its head
>into our 'modern' aviation world.=C2 Things
>Change - Way Back in Bob N.'s day of King Air
>and simple bundles of wires with ALL cables
>bundled together is No Longer.=C2 We have new
>items entering the market place every day and
>many produce noise.=C2 We have to do what ever we
>can to reduce and eliminate all sorts of
>noise.=C2 Here on this list we spoke about the
>modern noise from LED's.=C2 It's not going away.
Barry, your talking about hardware that would
not be allowed onto a production airplane . . .
twisting power wires never helped any
noise issue. It has mitigated a magnetic
interference situation with windshield mounted
compasses . . . twisting the wires (or using
a shielded wire for outbound and return) on
the light bulb reduced heading errors from that
source to zero.
I have designed, built, qualified and integrated dozens
of appliances onto type certificated airplanes
with the notion that EVERY qualified device should
live happily with all other qualified devices
with NO special attention on the part of the
installer/system integrator with respect to noise.
Installation instructions were expected to include
special considerations with respect to environment,
orientation, mechanical mounting, etc. But special
considerations with respect to noise would be
hard to sell to the ACO.
One of the last noise issues I worked at Beech was
a newly qualified cabin HVAC system wherein the
rear mounted blower hosed the ADF.
Ran the blower in our lab and found it to be
exceedingly noisy.
This device was recently 'qualified' by a lab in
Dallas. I drove down and visited the lab. Looked
a their test set up and talked with the test technician.
Looked at his test data plot. "Wow", says he, "this
the the quietest motor I've ever tested". To be sure
the plots didn't rise off the receiver's noise floor!
We poked around the EMC test cell and found that the
coax through the wall to their conducted noise
transformer had been disconnected . . .
Fortunately, there were only about a dozen products
they had erroneously holy watered in that test
cell . . easy to spot in the test data. The
test technician wasn't experienced enough to know that
the noise was never zero. It just had to be below
a pass/fail line.
We had a dozen systems in the field. Modifying
the blower would call for re-qualification. Made
a midnight run to Captor Corporation where
a fellow gray-beard and I crafted a filter-connector
to go on the end of the harness that mated with the
blower.
I had worked with this fellow for decades on
a host of filter designs but this was the
first time we met face to face and hammered
out a solution together. He was semi-retired
and I was getting close . . . it was a
great experience.
Emacs!
Had to do this kind of thing on another airplane
where vintage starter-generator controllers (never
qualified to modern design philosophies) needed
a bunch of capacitors installed under the
connector back shell.
Emacs!
These noise problems were the result of poorly
designed and/or qualified devices. The fact
that they were fielded made it necessary to
craft 'band aids' to bring them into compliance.
But these are very rare circumstances. The
noises from products you allude to would
not be mitigated by line twisting or repositioning
of wires. Adding some filtering might do
the job . . . we've done that on several
devices discussed here on the List.
Yes, many of my anecdotes have some age on
them . . . been doing this for a long time.
But the SCIENCE hasn't materially changed in
my lifetime.
And by the way, production airplanes are generally
wired with white wire.
Bob . . .
Message 5
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| Subject: | Re: Question: can these wires be put in one wire |
bundle?
At 11:01 PM 10/7/2018, you wrote:
>
>Noise problems are sometimes present no matter how careful the builder has
>been. That is why I read this forum, just to get ideas how to chase them.
>When a friend ask me for ideas on how to find an intermittent source of
>noise in his GlassStar, I gave him some ideas based on what I had learned
>here. He had no luck and was just ready to give up when he accidently
>noticed his HOBBS meter was running intermittently. He had a standard
>arrangement where a switch in the oil pressure line turned on the HOBBS
>meter so it recorded actual engine run time. When he replaced the oil
>pressure switch that activated the HOBBS meter, the intermittent noise went
>away. That was a total accidental situation. I doubt anyone would have
>suspected a bad set of points in an oil pressure switch of causing the
>problem.
>
>You learn something new every day if you just pay attention to what you can
>learn by other's experiences.
Interesting anecdote! Thanks for sharing.
Yes, MOST noise problems are vexing . . . often difficult
to analyze and fix. This is because they are rare and
seldom follow a historical script. Given
that all qualified appliances are 99.99% guaranteed
to live in one happy community, issues that do arise
tend to be one-of, weird little thing that nobody has
seen before and may never see again.
This is why prophylactics beyond the legacy catalog
of good practices are of no demonstrable value.
I am reminded of a call I received from one of my
seminar attendees about 25 years ago. He described
a litany of techniques he had applied to his Long-Ez
with the goal of mitigating noise issues. He had
shielded all his wires, separated certain wires from
others and had crafted a 'ground system' that was
difficult to visualize from the conversation.
I was somewhat astounded and asked, "What kind of
noise problem do you have?"
"Oh, no problem," says he, "I haven't flown the
airplane yet. Just want to make sure I've got
all the bases covered."
I suggested that he speak with builders already
flying who are happy with their installations.
I further suggested that he would save some weight,
bulk and complexity by pulling out all of what
he'd already put in and start over. If he did
encounter a noise problem, it would most likely
be easy to fix.
Had occasion to communicate with him years later
and he was happily flying a lighter, simpler
system.
Bob . . .
Message 6
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| Subject: | Re: Rear battery earthing structure |
On 10/7/2018 7:22 PM, Robert L. Nuckolls, III wrote:
> At 05:46 PM 10/7/2018, you wrote:
>> <nwparkinson@btopenworld.com>
>>
>> Hi Everybody.
>>
>> Im building an RV8 with a rear battery location.
>>
>> Can I please have some advice on the earthing structure . Can I just
>> earth the battery to the structure in the rear , then take it the
>> common earth at the panel ? Or is it worth running some asw2 cable to
>> earth the panel , or the engine ??
>
> Ground battery locally
>
> http://aeroelectric.com/Pictures/Batteries/Battery_Install_OBrien_3.jpg
> http://aeroelectric.com/Pictures/Grounding/Local_Battery_Grounds_1.jpg
>
> Install ground bus on firewall.
>
> http://aeroelectric.com/Pictures/Grounding/Forest_of_Tabs_Ground_Kit.pdf
> http://aeroelectric.com/Pictures/Grounding/gnd_bus.jpg
> <http://aeroelectric.com/Pictures/Grounding/gnd_bus.jpg>
>
>
> Run braided-flat-wire
> from crankcase to firewall ground stud.
>
> http://aeroelectric.com/Pictures/Grounding/Braided%20Copper%20Bond%20Straps.jpg
>
>
>> I will have some rear avionics equipment , should I run the earth
>> from the panel to these ? Or just tap of the structure locally ?
>
> What kind of avionics? Anything with audio or digital
> signal leads?
>
> Bob . . .
>
To OP: I have an RV10 with a 2 rear batteries, a ground bus on firewall
and a braided flat wire from crankcase to firewall ground stud. No
problems (7 years flying)
In addition I have a variety of boxes installed in rear including
Navworx ADSB, strobe unit, Magnetometers (sic), and ELT. I followed the
installation instructions as Bob suggested. No problems.
---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
Message 7
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| Subject: | A brown-out alternative? |
I mentioned a few days ago that I thought I
had yet another solution to the perennial brown-out
gremlin.
This discussion has been going on for quite some time
and many hours have been expended on a search for the
practical if not elegant solution.
Background:
It seems a number of entrepreneurial suppliers to the
OBAM aircraft industry have introduced devices with desirable
features at prices attractive to the community.
With the advent of PM starters (gawd awful inrush currents)
and a quest for smaller and lighter batteries, the initial
current draw during cranking would depress the battery voltage
to some value where these devices would reset. I think Greg's
Blue Mountain EFIS system was one of the first victims of the
dreaded CBOT(cranking brown out transient).
Many of the first victims were candidates for simple
energy storage networks comprised of super-capacitors. Seems
their current draw was so small and the CBOT so short that
the capacitors would fill in the energy gap.
Over the years it seems that the desire for more energy
over longer CBOTs made the capacitor-storage solution
marginal if not impractical.
Then came some battery based products that offered
both heavier current support during CBOT but let you
do some things like run some electro-whizzies for some time
before cranking the engine.
Only down-side being it adds a battery to the airplane.
Batteries are like house plants . . . mis-treat them slightly
and they will probably recover . . . mis-treat them badly
and they're T.U. Some batteries were ensconced within an
electronic protective shell to reduce probability of
mis-treatment. Good. But it adds to cost.
Then there's the issue of service life. ALL batteries of
any type used for any task on the airplane eventually
need replacement. This feature DEMANDS preventative maintenance
attention from the operator for monitoring condition of
the battery(ies) with go/no-go criteria for replacement.
I've done dozens of FMEA and reliability studies where
adding batteries to the system may have offered builders
some warm-n-fuzzy feelings . . . even to the degree that
they quit worrying about the ship's main battery.
Given that a properly maintained battery is the single
most reliable source of energy on the airplane, it did
not make sense to me that adding more battery(ies) was
more desirable than simply taking care of the battery
you already have . . . and doing the energy studies
to see that its capacity was adequate to all anticipated
flight conditions.
So, with the one-battery per airplane design goal in
mind and CBOTs still lurking in the wings, I would offer
the architecture below for the List's consideration:
Emacs!
DC to DC up-converters are jelly-bean parts. Dozens
of candidates are available for less than $10 which
will boost 10 or so volts, depressed battery to 14v . . .
well above the roll-over voltage for potential CBOT
victims.
With the architecture shown above, the e-bus boost
feature is available only while the e-bus alternate
feed switch is in the NORMAL position . . . and only
while power is being applied to the starter contactor
via crew controlled push button.
The DC/DC converter can be of any pedigree since
(1) it's never active during normal ops (EMC issues
disappear)
(2) functionality is pre-flight tested every flight
cycle.
(3) It is not a safety of flight issue since it's
only active for tens of milliseconds during
cranking -AND- failure of the converter does
not disable any accessory neeed for comfortable
termination of flight.
(4) Since it is active for perhaps a second each
flight cycle and average utilization of the
light aircraft is less than 100 fligh cycles
per year, the service life of these devices
should exceed lifetime of the airframe.
If there is a 'downside' to this approach, I suppose
that it causes the crew to 'load' the ship's battery
for preflight ops such as ATIS and clearance collection.
But recall that we're assuming that the ship's battery
will be sized and maintained to meet design goals. In
the normal world, cranking the engine takes perhaps 5%
of battery capacity. Preflight ops of electro-whizzies
should require no more than that. That energy will be
replaced in the first few minutes of flight.
I humbly suggest that the technique cited above
will deal with 100% of CBOT issues at zero cost of
ownership beyond initial purchase and installation
of the system and zero impact on system reliability
and performance. It also encourages the owner to
conduct due diligence in the maintenance of the
ship's battery since there are NO standby batteries
tending to lull one into a false sense of system
reliability.
Cogent arguments pro and con are most welcome.
Bob . . .
Message 8
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| Subject: | B lead circuit breaker |
I have a Plane Power Alternator on my RV-6A and lately with the Aero Flash strobes
on at some point the B lead CB will pop. It does reset. Today I flew a
2 leg cross country for 4 hours total, all with the strobes off after the popping
event 2 minutes into the flight. How would I determine if their is a problem
with the strobes that might cause this problem?
Thanks for any hints.
Ron Burnett
May you have the Lord's blessings today!
Sent from my iPad
Message 9
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| Subject: | Re: A brown-out alternative? |
Bob,
That looks very clever. I think that it will work.
Is my logic here correct? For my plane, which has two alternators and no
endurance bus, I would create an "EFIS" bus, running only the EFIS, and fed
via two diodes, one to the main bus and the second to the DC/DC upverter.
For those of us who don't live and breathe this stuff, can you post a few
typical part numbers for the upverter and the diodes? Or typical specs?
Thank you for attending to this issue.
-- Art Z.
On Mon, Oct 8, 2018 at 8:28 PM Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> So, with the one-battery per airplane design goal in
> mind and CBOTs still lurking in the wings, I would offer
> the architecture below for the List's consideration:
>
>
> [image: Emacs!]
>
>
--
https://CheerfulCurmudgeon.com/
*"We do not see the world as it is. We see the world as we are."*
Message 10
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| Subject: | A brown-out alternative? |
From: Robert L. Nuckolls, III
Sent: Monday, October 8, 2018 9:12 PM
Subject: AeroElectric-List: A brown-out alternative?
I mentioned a few days ago that I thought I
had yet another solution to the perennial brown-out
gremlin.
This discussion has been going on for quite some time
and many hours have been expended on a search for the
practical if not elegant solution.
Background:
It seems a number of entrepreneurial suppliers to the
OBAM aircraft industry have introduced devices with desirable
features at prices attractive to the community.
With the advent of PM starters (gawd awful inrush currents)
and a quest for smaller and lighter batteries, the initial
current draw during cranking would depress the battery voltage
to some value where these devices would reset. I think Greg's
Blue Mountain EFIS system was one of the first victims of the
dreaded CBOT(cranking brown out transient).
Many of the first victims were candidates for simple
energy storage networks comprised of super-capacitors. Seems
their current draw was so small and the CBOT so short that
the capacitors would fill in the energy gap.
Over the years it seems that the desire for more energy
over longer CBOTs made the capacitor-storage solution
marginal if not impractical.
Then came some battery based products that offered
both heavier current support during CBOT but let you
do some things like run some electro-whizzies for some time
before cranking the engine.
Only down-side being it adds a battery to the airplane.
Batteries are like house plants . . . mis-treat them slightly
and they will probably recover . . . mis-treat them badly
and they're T.U. Some batteries were ensconced within an
electronic protective shell to reduce probability of
mis-treatment. Good. But it adds to cost.
Then there's the issue of service life. ALL batteries of
any type used for any task on the airplane eventually
need replacement. This feature DEMANDS preventative maintenance
attention from the operator for monitoring condition of
the battery(ies) with go/no-go criteria for replacement.
I've done dozens of FMEA and reliability studies where
adding batteries to the system may have offered builders
some warm-n-fuzzy feelings . . . even to the degree that
they quit worrying about the ship's main battery.
Given that a properly maintained battery is the single
most reliable source of energy on the airplane, it did
not make sense to me that adding more battery(ies) was
more desirable than simply taking care of the battery
you already have . . . and doing the energy studies
to see that its capacity was adequate to all anticipated
flight conditions.
So, with the one-battery per airplane design goal in
mind and CBOTs still lurking in the wings, I would offer
the architecture below for the List's consideration:
DC to DC up-converters are jelly-bean parts. Dozens
of candidates are available for less than $10 which
will boost 10 or so volts, depressed battery to 14v . . .
well above the roll-over voltage for potential CBOT
victims.
With the architecture shown above, the e-bus boost
feature is available only while the e-bus alternate
feed switch is in the NORMAL position . . . and only
while power is being applied to the starter contactor
via crew controlled push button.
The DC/DC converter can be of any pedigree since
(1) it's never active during normal ops (EMC issues
=C2-=C2-=C2- disappear)
(2) functionality is pre-flight tested every flight
=C2-=C2-=C2- cycle.
(3) It is not a safety of flight issue since it's
=C2-=C2-=C2- only active for tens of milliseconds during
=C2-=C2-=C2- cranking -AND- failure of the converter does
=C2-=C2-=C2- not disable any accessory neeed for comfortable
=C2-=C2-=C2- termination of flight.
(4) Since it is active for perhaps a second each
=C2-=C2-=C2- flight cycle and average utilization of the
=C2-=C2-=C2- light aircraft is less than 100 fligh cycles
=C2-=C2-=C2- per year, the service life of these devices
=C2-=C2-=C2- should exceed lifetime of the airframe.
If there is a 'downside' to this approach, I suppose
that it causes the crew to 'load' the ship's battery
for preflight ops such as ATIS and clearance collection.
But recall that we're assuming that the ship's battery
will be sized and maintained to meet design goals. In
the normal world, cranking the engine takes perhaps 5%
of battery capacity. Preflight ops of electro-whizzies
should require no more than that. That energy will be
replaced in the first few minutes of flight.
I humbly suggest that the technique cited above
will deal with 100% of CBOT issues at zero cost of
ownership beyond initial purchase and installation
of the system and zero impact on system reliability
and performance. It also encourages the owner to
conduct due diligence in the maintenance of the
ship's battery since there are NO standby batteries
tending to lull one into a false sense of system
reliability.
Cogent arguments pro and con are most welcome.
=C2- Bob . . .
Am I correct in assuming that the right hand side of the start push button
should be tied through a fuse to the main bus?
Roger
Message 11
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| Subject: | Re: B lead circuit breaker |
Ron,
Do you have a voltmeter in the plane? I am guessing that the circuit
breaker is popping because the voltage is going too high. Maybe a voltage
regulator problem.
-- Art Z.
On Mon, Oct 8, 2018 at 8:34 PM Ron Burnett <ronburnett@charter.net> wrote:
> ronburnett@charter.net>
>
> I have a Plane Power Alternator on my RV-6A and lately with the Aero Flash
> strobes on at some point the B lead CB will pop. It does reset. Today I
> flew a 2 leg cross country for 4 hours total, all with the strobes off
> after the popping event 2 minutes into the flight. How would I determine if
> their is a problem with the strobes that might cause this problem?
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Message 12
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| Subject: | Re: A brown-out alternative? |
On 10/8/2018 8:09 PM, Robert L. Nuckolls, III wrote:
> I mentioned a few days ago that I thought I
> had yet another solution to the perennial brown-out
> gremlin.
>
> This discussion has been going on for quite some time
> and many hours have been expended on a search for the
> practical if not elegant solution.
>
> Background:
>
> It seems a number of entrepreneurial suppliers to the
> OBAM aircraft industry have introduced devices with desirable
> features at prices attractive to the community.
>
> With the advent of PM starters (gawd awful inrush currents)
> and a quest for smaller and lighter batteries, the initial
> current draw during cranking would depress the battery voltage
> to some value where these devices would reset. I think Greg's
> Blue Mountain EFIS system was one of the first victims of the
> dreaded CBOT(cranking brown out transient).
>
> Many of the first victims were candidates for simple
> energy storage networks comprised of super-capacitors. Seems
> their current draw was so small and the CBOT so short that
> the capacitors would fill in the energy gap.
>
> Over the years it seems that the desire for more energy
> over longer CBOTs made the capacitor-storage solution
> marginal if not impractical.
>
> Then came some battery based products that offered
> both heavier current support during CBOT but let you
> do some things like run some electro-whizzies for some time
> before cranking the engine.
>
> Only down-side being it adds a battery to the airplane.
>
> Batteries are like house plants . . . mis-treat them slightly
> and they will probably recover . . . mis-treat them badly
> and they're T.U. Some batteries were ensconced within an
> electronic protective shell to reduce probability of
> mis-treatment. Good. But it adds to cost.
>
> Then there's the issue of service life. ALL batteries of
> any type used for any task on the airplane eventually
> need replacement. This feature DEMANDS preventative maintenance
> attention from the operator for monitoring condition of
> the battery(ies) with go/no-go criteria for replacement.
>
> I've done dozens of FMEA and reliability studies where
> adding batteries to the system may have offered builders
> some warm-n-fuzzy feelings . . . even to the degree that
> they quit worrying about the ship's main battery.
>
> Given that a properly maintained battery is the single
> most reliable source of energy on the airplane, it did
> not make sense to me that adding more battery(ies) was
> more desirable than simply taking care of the battery
> you already have . . . and doing the energy studies
> to see that its capacity was adequate to all anticipated
> flight conditions.
>
> So, with the one-battery per airplane design goal in
> mind and CBOTs still lurking in the wings, I would offer
> the architecture below for the List's consideration:
>
>
> Emacs!
>
> DC to DC up-converters are jelly-bean parts. Dozens
> of candidates are available for less than $10 which
> will boost 10 or so volts, depressed battery to 14v . . .
> well above the roll-over voltage for potential CBOT
> victims.
>
> With the architecture shown above, the e-bus boost
> feature is available only while the e-bus alternate
> feed switch is in the NORMAL position . . . and only
> while power is being applied to the starter contactor
> via crew controlled push button.
>
> The DC/DC converter can be of any pedigree since
>
> (1) it's never active during normal ops (EMC issues
> disappear)
>
> (2) functionality is pre-flight tested every flight
> cycle.
>
> (3) It is not a safety of flight issue since it's
> only active for tens of milliseconds during
> cranking -AND- failure of the converter does
> not disable any accessory neeed for comfortable
> termination of flight.
>
> (4) Since it is active for perhaps a second each
> flight cycle and average utilization of the
> light aircraft is less than 100 fligh cycles
> per year, the service life of these devices
> should exceed lifetime of the airframe.
>
> If there is a 'downside' to this approach, I suppose
> that it causes the crew to 'load' the ship's battery
> for preflight ops such as ATIS and clearance collection.
>
> But recall that we're assuming that the ship's battery
> will be sized and maintained to meet design goals. In
> the normal world, cranking the engine takes perhaps 5%
> of battery capacity. Preflight ops of electro-whizzies
> should require no more than that. That energy will be
> replaced in the first few minutes of flight.
>
> I humbly suggest that the technique cited above
> will deal with 100% of CBOT issues at zero cost of
> ownership beyond initial purchase and installation
> of the system and zero impact on system reliability
> and performance. It also encourages the owner to
> conduct due diligence in the maintenance of the
> ship's battery since there are NO standby batteries
> tending to lull one into a false sense of system
> reliability.
>
> Cogent arguments pro and con are most welcome.
>
> Bob . . .
>
I like it; I might try it out on my old RV-4 electrical system. It's a
pretty simple, crude system, but the Matronics fuel flow meter reboots
on startup. Only potential downside I can see is that some avionics
systems may well draw a total of 5 or 6 amps. If battery voltage drops
down in the 8-9 volt range, you could see an additional 8 or 10 amps of
load on the start PB. There are some planes out there that have the
start PB feeding a starter with built-in solenoid/contactor; in those
cases, the PB may be pretty heavily loaded.
I toyed with the idea of using one of those 'switchers' to replace the
isolation diode if I'd used a dual battery system (instead of the dual
alternator system chosen) on my electronic injected engine installation.
Charlie
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| Subject: | Re: B lead circuit breaker |
Art,
Yes, the volt meter shows 14.2 to 14.3 range in flight, unless it spikes I g
uess?
Ron Burnett
May you have the Lord's blessings today!
Sent from my iPad
> On Oct 8, 2018, at 8:51 PM, Art Zemon <art@zemon.name> wrote:
>
> Ron,
>
> Do you have a voltmeter in the plane? I am guessing that the circuit break
er is popping because the voltage is going too high. Maybe a voltage regulat
or problem.
>
> -- Art Z.
>
>> On Mon, Oct 8, 2018 at 8:34 PM Ron Burnett <ronburnett@charter.net> wrote
:
net>
>>
>> I have a Plane Power Alternator on my RV-6A and lately with the Aero Flas
h strobes on at some point the B lead CB will pop. It does reset. Today I
flew a 2 leg cross country for 4 hours total, all with the strobes off afte
r the popping event 2 minutes into the flight. How would I determine if thei
r is a problem with the strobes that might cause this problem?
> --
> https://CheerfulCurmudgeon.com/
>
> "We do not see the world as it is. We see the world as we are."
Message 14
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| Subject: | Re: B lead circuit breaker |
At 08:18 PM 10/8/2018, you wrote:
>
>I have a Plane Power Alternator on my RV-6A and lately with the Aero
>Flash strobes on at some point the B lead CB will pop. It does
>reset. Today I flew a 2 leg cross country for 4 hours total, all
>with the strobes off after the popping event 2 minutes into the
>flight. How would I determine if their is a problem with the strobes
>that might cause this problem?
>
>Thanks for any hints.
>
>Ron Burnett
What size is your alternator. What size is
your B-lead breaker.
Bob . . .
Message 15
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| Subject: | Re: A brown-out alternative? |
nuckolls.bob(at)aeroelect wrote:
> I mentioned a few days ago that I thought I had yet another solution to the perennial
brown-out gremlin.
>
> [SNIP]
>
> Cogent arguments pro and con are most welcome.
Clever idea, Bob -- I like it!
As Charlie mentioned, the current drawn by the DC-DC boost converter could be significant,
and would of course increase with decreasing supply voltage. There's
also the likelihood of substantial inrush current at start-up. Unless an
adequately beefy start switch is specified, its contacts might suffer from making
and breaking this load.
This problem might be mitigated by powering the DC-DC boost converter either from
the load side of the starter contactor (in parallel with the starter) or via
a cube-type automotive relay. This would also simplify adding this design as
a retrofit, since the start switch wiring/CB/fuse would not have to be upgraded
to carry the boost converter's supply current.
A bit of eBay searching resulted in several potential candidates for the boost
converter. These first two are quite small and conveniently packaged; they appear
to be the same unit in different enclosures. Power output might be marginal
and their 11V max input might be an issue:
https://www.ebay.com/itm/323360110037
https://www.ebay.com/itm/123391340337
These two are significantly more powerful and have a wider input voltage range:
https://www.ebay.com/itm/321795754199
https://www.ebay.com/itm/263796566855
If one didn't want to use an eBay boost converter of unknown quality, Digi-Key
offers this unit, which is specified for high vibration and extreme temperatures
in railroad use, but doesn't cost a fortune. However, its minimum input is
9V, which might not be low enough in some cases.
https://www.digikey.com/short/jnnh51
Eric
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=483720#483720
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