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nuckolls.bob(at)aeroelect
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 Posted: Wed Jun 10, 2020 9:58 am Post subject: How about Z102? |
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At 04:58 PM 6/9/2020, you wrote:
| Quote: | --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com>
Alec, everything you wrote is true. Keep in mind that I was not necessarily
recommending two batteries. Someone who has an electrically dependent
engine with only one alternator might want to have two batteries. If the
alternator failed a long way from an airport, would that person prefer to have
one 2-year-old battery, or . . one 2-year-old battery plus one 4-year-old
battery? Some pilots do not replace their battery until it will not crank the
engine any more. Many batteries last 5 or more years. The nice thing about
experimental aircraft is that the builder designs the electrical system the way
that they want to. |
Let's harken back a few years . . . about
26 to be more exact when the OBAM aviation
community was in similar discussions
about second batteries. Then the triggering
technology was a constellation of electronic ignition
systems being offered to home built aviation.
I wrote an article for SA that massaged some
ideas for managing a second battery in a ship
fitted with dual electronic ignition systems.
https://tinyurl.com/y8cpo3wo
About 10 years later, this product came into being
offering a means for crew selected, manual or
automatic management of a second battery installed
to support flight critical systems in single
alternator aircraft.
https://tinyurl.com/nxmo3us
The adaptation of an automotive engine to
aircraft is unique and not well supported by
the Z101 Tinker-Toy approach to system architecture.
It would seem that neither the endurance bus
nor engine bus are optional. Further, given
the relatively high energy demands of some
engines (10+ Amps), the term 'endurance' is
no longer applicable. The idea of consuming
all fuel aboard during battery-only ops is
simply unrealistic.
Sadly, it seems necessary to apply the term
'emergency' to an alternator-out situation;
reversion to battery-only ops fosters a sense of
urgency to get the wheels on the ground ASAP!
I've massaged Z101 into a proposed Z102
architecture that offers a means for incorporation
of a second battery with a minimum of $time$
expended on monitoring for continued airworthiness.
I've posted the first iteration for the List
to sift . . .
https://tinyurl.com/ybgta8bb
In this proposal, the aux battery is the same
part number as the main battery. It is fitted
with a robust contactor that permits large
current flows to and from the aux battery for
(1) discharge during cranking assist and (2)
un-restricted charging from the ship's
alternator.
Again, all the buses are multiple feed path;
all buses are hot any time the main bus is hot.
This lends itself to single switch activation
of the DC power system.
Depending on flight conditions the aux bus
may be re-configured for main battery only
ops; the engine bus may be re-configured for
aux battery only ops.
As with Z101, no mis-position (aside from
OFF) puts the airframe at risk.
The aux battery is automatically connected to
the main bus any time the bus voltage exceeds
13.5 volts . . . i.e. the alternator is
running. As the most capable battery on
the airplane, the aux battery is dedicated
to engine operations.
Preflight checks are simple: Select aux bus
alt feed before engine start . . . observe
items on that bus are energized . . . all else
is dark. During engine run-up, select ENGINE
BUS AUX feed . . . note that voltage on the
bus rises by approx 0.7 volts while the aux
feed is selected.
With two identical batteries, the preventative
maintenance protocol reduces to periodic
replacement of aux battery with a new one while
moving the seldom taxed device into the main
battery position.
A more modern incarnation of the battery
management module is in the design phase.
It easily fits inside the backshell of a
15-pin d-sub.
https://tinyurl.com/ycr43882
Bob . . .
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ceengland7(at)gmail.com
Guest
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| Posted: Wed Jun 10, 2020 11:49 am Post subject: How about Z102? |
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On Wed, Jun 10, 2020 at 1:06 PM Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
| Quote: | At 04:58 PM 6/9/2020, you wrote:
| Quote: | --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>
Alec, everything you wrote is true. Keep in mind that I was not necessarily
recommending two batteries. Someone who has an electrically dependent
engine with only one alternator might want to have two batteries. If the
alternator failed a long way from an airport, would that person prefer to have
one 2-year-old battery, or . . one 2-year-old battery plus one 4-year-old
battery? Some pilots do not replace their battery until it will not crank the
engine any more. Many batteries last 5 or more years. The nice thing about
experimental aircraft is that the builder designs the electrical system the way
that they want to. |
  Let's harken back a few years . . . about
  26 to be more exact when the OBAM aviation
  community was in similar discussions
  about second batteries. Then the triggering
  technology was a constellation of electronic ignition
  systems being offered to home built aviation.
  I wrote an article for SA that massaged some
  ideas for managing a second battery in a ship
  fitted with dual electronic ignition systems.
https://tinyurl.com/y8cpo3wo
  About 10 years later, this product came into being
  offering a means for crew selected, manual or
  automatic management of a second battery installed
  to support flight critical systems in single
  alternator aircraft. Â
https://tinyurl.com/nxmo3us
  The adaptation of an automotive engine to
  aircraft is unique and not well supported by
  the Z101 Tinker-Toy approach to system architecture.
  It would seem that neither the endurance bus
  nor engine bus are optional. Further, given
  the relatively high energy demands of some
  engines (10+ Amps), the term 'endurance' is
  no longer applicable. The idea of consuming
  all fuel aboard during battery-only ops is
  simply unrealistic.
  Sadly, it seems necessary to apply the term
  'emergency' to an alternator-out situation;
  reversion to battery-only ops fosters a sense of
  urgency to get the wheels on the ground ASAP!
  I've massaged Z101 into a proposed Z102
  architecture that offers a means for incorporation
  of a second battery with a minimum of $time$
  expended on monitoring for continued airworthiness.
  I've posted the first iteration for the List
  to sift . . .
https://tinyurl.com/ybgta8bb
  In this proposal, the aux battery is the same
  part number as the main battery. It is fitted
  with a robust contactor that permits large
  current flows to and from the aux battery for
  (1) discharge during cranking assist and (2)
  un-restricted charging from the ship's
  alternator.
  Again, all the buses are multiple feed path;
  all buses are hot any time the main bus is hot.
  This lends itself to single switch activation
  of the DC power system.
  Depending on flight conditions the aux bus
  may be re-configured for main battery only
  ops; the engine bus may be re-configured for
  aux battery only ops.
  As with Z101, no mis-position (aside from
  OFF) puts the airframe at risk.
  The aux battery is automatically connected to
  the main bus any time the bus voltage exceeds
  13.5 volts . . . i.e. the alternator is
  running. As the most capable battery on
  the airplane, the aux battery is dedicated
  to engine operations.
  Preflight checks are simple: Select aux bus
  alt feed before engine start . . . observe
  items on that bus are energized . . . all else
  is dark. During engine run-up, select ENGINE
  BUS AUX feed . . . note that voltage on the
  bus rises by approx 0.7 volts while the aux
  feed is selected.
  With two identical batteries, the preventative
  maintenance protocol reduces to periodic
  replacement of aux battery with a new one while
  moving the seldom taxed device into the main
  battery position.
  A more modern incarnation of the battery
  management module is in the design phase.
  It easily fits inside the backshell of a
  15-pin d-sub.
https://tinyurl.com/ycr43882
 Bob . . .
|
The irony here is that with automotive conversions it's typically much easier to add a 2nd full size alternator (at less weight penalty than a 2nd equal sized SLA battery), and less money, if you're planning on buying Odyssey branded bats. Very few of us are willing to add air conditioners in light a/c, so there's the hole (and pulley) for a 2nd alt.
Charlie
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kenryan
Joined: 20 Oct 2009
Posts: 426
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| Posted: Wed Jun 10, 2020 12:19 pm Post subject: How about Z102? |
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Regarding proposed Z102 thanks for taking time to developing an architecture specific to auto conversion engines. One comment I have after reviewing is that from what I have seen, many (probably most?) auto conversions seem to use denso alternators with internal regulators. I think it may be relatively uncommon that these alternators are modified so that their regulators are moved to the external, or replaced with more conventional aircraft alternators. I therefore wonder if the architecture might be more useful if it also accounted for this idiosyncrasy of using a single internally regulated alternator?
Ken
On Wed, Jun 10, 2020 at 10:06 AM Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
| Quote: | At 04:58 PM 6/9/2020, you wrote:
| Quote: | --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>
Alec, everything you wrote is true. Keep in mind that I was not necessarily
recommending two batteries. Someone who has an electrically dependent
engine with only one alternator might want to have two batteries. If the
alternator failed a long way from an airport, would that person prefer to have
one 2-year-old battery, or . . one 2-year-old battery plus one 4-year-old
battery? Some pilots do not replace their battery until it will not crank the
engine any more. Many batteries last 5 or more years. The nice thing about
experimental aircraft is that the builder designs the electrical system the way
that they want to. |
  Let's harken back a few years . . . about
  26 to be more exact when the OBAM aviation
  community was in similar discussions
  about second batteries. Then the triggering
  technology was a constellation of electronic ignition
  systems being offered to home built aviation.
  I wrote an article for SA that massaged some
  ideas for managing a second battery in a ship
  fitted with dual electronic ignition systems.
https://tinyurl.com/y8cpo3wo
  About 10 years later, this product came into being
  offering a means for crew selected, manual or
  automatic management of a second battery installed
  to support flight critical systems in single
  alternator aircraft. Â
https://tinyurl.com/nxmo3us
  The adaptation of an automotive engine to
  aircraft is unique and not well supported by
  the Z101 Tinker-Toy approach to system architecture.
  It would seem that neither the endurance bus
  nor engine bus are optional. Further, given
  the relatively high energy demands of some
  engines (10+ Amps), the term 'endurance' is
  no longer applicable. The idea of consuming
  all fuel aboard during battery-only ops is
  simply unrealistic.
  Sadly, it seems necessary to apply the term
  'emergency' to an alternator-out situation;
  reversion to battery-only ops fosters a sense of
  urgency to get the wheels on the ground ASAP!
  I've massaged Z101 into a proposed Z102
  architecture that offers a means for incorporation
  of a second battery with a minimum of $time$
  expended on monitoring for continued airworthiness.
  I've posted the first iteration for the List
  to sift . . .
https://tinyurl.com/ybgta8bb
  In this proposal, the aux battery is the same
  part number as the main battery. It is fitted
  with a robust contactor that permits large
  current flows to and from the aux battery for
  (1) discharge during cranking assist and (2)
  un-restricted charging from the ship's
  alternator.
  Again, all the buses are multiple feed path;
  all buses are hot any time the main bus is hot.
  This lends itself to single switch activation
  of the DC power system.
  Depending on flight conditions the aux bus
  may be re-configured for main battery only
  ops; the engine bus may be re-configured for
  aux battery only ops.
  As with Z101, no mis-position (aside from
  OFF) puts the airframe at risk.
  The aux battery is automatically connected to
  the main bus any time the bus voltage exceeds
  13.5 volts . . . i.e. the alternator is
  running. As the most capable battery on
  the airplane, the aux battery is dedicated
  to engine operations.
  Preflight checks are simple: Select aux bus
  alt feed before engine start . . . observe
  items on that bus are energized . . . all else
  is dark. During engine run-up, select ENGINE
  BUS AUX feed . . . note that voltage on the
  bus rises by approx 0.7 volts while the aux
  feed is selected.
  With two identical batteries, the preventative
  maintenance protocol reduces to periodic
  replacement of aux battery with a new one while
  moving the seldom taxed device into the main
  battery position.
  A more modern incarnation of the battery
  management module is in the design phase.
  It easily fits inside the backshell of a
  15-pin d-sub.
https://tinyurl.com/ycr43882
 Bob . . .
|
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user9253
Joined: 28 Mar 2008
Posts: 1927
Location: Riley TWP Michigan
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| Posted: Wed Jun 10, 2020 3:05 pm Post subject: Re: How about Z102? |
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|
Bob, if two batteries are connected in parallel and one of the batteries
develops a shorted cell, will the good battery discharge into the bad battery?
If yes, would the rate of discharge be significant enough to quickly reduce
the good battery voltage to that of the bad battery?
Thanks
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Joe Gores |
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nuckolls.bob(at)aeroelect
Guest
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| Posted: Thu Jun 11, 2020 6:35 am Post subject: How about Z102? |
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At 03:12 PM 6/10/2020, you wrote:
| Quote: | Regarding proposed Z102 thanks for taking time to developing an architecture specific to auto conversion engines. One comment I have after reviewing is that from what I have seen, many (probably most?) auto conversions seem to use denso alternators with internal regulators. I think it may be relatively uncommon that these alternators are modified so that their regulators are moved to the external, or replaced with more conventional aircraft alternators. I therefore wonder if the architecture might be more useful if it also accounted for this idiosyncrasy of using a single internally regulated alternator?
Ken |
This has been an ongoing debate on these pages
decades. I've sorta taken the tack that we should
strive to publish and recommend the best we know
how to do as opposed to becoming an echo chamber
for concepts from other venues.
To be sure, reliability of COTS alternators
is very high . . . in fact, I've been told there
are STCs now for adapting COTS alternators
to TC aircraft sans ov protection. I've not
seen any such documents but it wouldn't surprise
me.
We'll have to leave adoption of such variants
up to the individual builder. For the foreseeable
future, I'll continue to strive for as much
failure tolerance as the technology and tools
at hand will offer.
Speaking of COTS alternators . . . Lister
Graeme Coates did an excellent piece on ND alternator
modifications published in Kitplanes last year.
You can see a copy of that article here:
https://tinyurl.com/yxmpw3on
. . . along with other writings on the same
subject.
Bob . . .
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