Today's Message Index:
----------------------
1. 05:00 AM - Re: Re: Re[3]: Tailwind Electrical System Drawing and Power Analysi (Gerry van Dyk)
2. 07:26 AM - Data logger for DC volts and amps (Jared Yates)
3. 09:17 AM - Re: Re[3]: Tailwind Electrical System Drawing and Power Analysi (user9253)
4. 10:11 AM - Re: Data logger for DC volts and amps (user9253)
5. 11:03 AM - Re: Data logger for DC volts and amps (Finn Lassen)
6. 01:53 PM - Re: Data logger for DC volts and amps (Peter Pengilly)
7. 02:36 PM - Re: Re[5]: Tailwind Electrical System Drawing and Power Analysis (Peter Pengilly)
8. 02:48 PM - Re: Re[3]: Tailwind Electrical System Drawing and Power Analysis (Peter Pengilly)
9. 03:51 PM - Re[7]: Tailwind Electrical System Drawing and Power Analysis (Gerry van Dyk)
10. 03:53 PM - Re[5]: Tailwind Electrical System Drawing and Power Analysis (Gerry van Dyk)
Message 1
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| Subject: | Re: Re[3]: Tailwind Electrical System Drawing |
and Power Analysi
Thanks for the notes Joe
Replace the 15A E-Bus fuse with a fusible link. It is not good practice
to have fuses in series.
Yep, makes good sense.
Locate the E-Bus relay near the battery bus.
I plan to locate the SD-8 regulator between the panel and firewall. The
battery and it's bus are behind the passenger seat. My plan is to
replace the relay that came in the alternator kit with a double pole
relay, and place it beside the regulator. I suppose I could have the
switch operate two separate relays, but that seems pretty clunky. Could
you please tell me what problem you see with the relay beside the
endurance bus rather than the battery bus?
In the event of over voltage, the crowbar module will smoke. Protect it wi
th a 3 amp fuse or circuit breaker.
This confused me for a while till I realized I've got the breaker in the wr
ong position. I need to have the breaker in the switch wire, not the alte
rnator feed line back to the battery bus. I'll correct this. B&C's wiring
drawing is calling for a 2 amp breaker.
The 2A fuse in the battery contactor coil circuit is a good idea. It will
protect against reversed battery polarity. (It happens)
It'll be a long wire making its way from the contactor, up between the seat
s, through the tunnel with the flap linkages, then up to the panel, so fusi
ng it is a no-brainer. ;^)
Consider using a Hall Effect sensor instead of a shunt, if compatible
with your Dynon.
Yes, the EMS-220 from Dynon is compatible with hall effect sensors. The
engine sensor kit came with the shunt so I'll use it till I find a need
to change it. Don't get me wrong, I like hall effect sensors, but I'm
too cheap to set aside something that works and buy something different.
;^)
The starter contactor diode is wired wrong. Connect the banded end to
the "S" terminal.
Connect the other end of the diode to the other end of the contactor
coil (ground).
I'm a little red-faced on this one. When I added it, I first had it
wired as you say, then a quick glance at the battery contactor made me
think it goes on those two contacts on the side. So I changed it.
Doh!!! I'll put it back right. Of course it needs to be across the
coil.
Thanks again Joe, I'll get these corrections made.
Gerry
------ Original Message ------
>From "user9253" <fransew@gmail.com>
To aeroelectric-list@matronics.com
Date 2023-12-29 5:53:34 PM
Subject AeroElectric-List: Re: Re[3]: Tailwind Electrical System Drawing
and Power Analysi
>
>Suggestions:
>Replace the 15A E-Bus fuse with a fusible link. It is not good practice t
o have fuses in series.
>Locate the E-Bus relay near the battery bus.
>In the event of over voltage, the crowbar module will smoke.
>Protect it with a 3 amp fuse or circuit breaker.
>The 2A fuse in the battery contactor coil circuit is a good idea.
>It will protect against reversed battery polarity. (It happens)
>Consider using a Hall Effect sensor instead of a shunt, if compatible with
your Dynon.
>The starter contactor diode is wired wrong. Connect the banded end to the
"S" terminal.
>Connect the other end of the diode to the other end of the contactor coil
(ground).
>
>--------
>Joe Gores
>
>
>Read this topic online here:
>
>http://forums.matronics.com/viewtopic.php?p=512985#512985
>
>
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| Subject: | Data logger for DC volts and amps |
Does anyone know of a device that will keep a log of current draw in the
.05-5A range, for 12-24 hours or so? I'm trying to troubleshoot an
intermittent battery drain but the usual multimeter requires me being there
and looking at it. The best alternative I have come up with so far is to
point a video camera at the multimeter but there must be a gadget for this.
Message 3
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| Subject: | Re: Re[3]: Tailwind Electrical System Drawing and Power |
Analysi
> Could you please tell me what problem you see with the relay beside the endurance
bus rather than the battery bus?
The pilot should have the ability to shut off all electrical power as close to
the source(s) as possible.
This is especially important in the event of smoke in the cockpit or an imminent
forced landing.
Avoid installing always-hot wires any distance from the battery, especially near
the engine.
A NTSB accident inspector once commented that fires are unlikely if the battery
is thrown clear of the wreckage.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=512989#512989
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| Subject: | Re: Data logger for DC volts and amps |
Here are a couple of other ideas:
Put a very small fuse in series with the battery cable. If the fuse blows,
you will know that current was flowing. Digikey 486-7110-1-ND
.
Put an analog wrist watch in series with the battery cable. Put a forward
biased diode in parallel with the watch to limit the voltage across the watch.
If the time on the watch changes, current was flowing.
.
Just don't turn the master switch on while testing. :-)
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=512990#512990
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| Subject: | Re: Data logger for DC volts and amps |
On 12/30/2023 10:26 AM, Jared Yates wrote:
> Does anyone know of a device that will keep a log of current draw in
> the .05-5A range, for 12-24 hours or so? I'm trying to troubleshoot an
> intermittent battery drain but the usual multimeter requires me being
> there and looking at it. The best alternative I have come up with so
> far is to point a video camera at the multimeter but there must be a
> gadget for this.
Maybe omething like this:
https://www.amazon.com/Triplett-VDL48-Voltage-USB-Datalogger/dp/B0CFCBXKRH/ref=sr_1_3?adgrpid=1225955794707457&hvadid=76622403291054&hvbmt=bp&hvdev=c&hvlocphy=94237&hvnetw=s&hvqmt=p&hvtargid=kwd-76622497037322%3Aloc-190&hydadcr=13412_13504749&keywords=data+logger+voltage&qid=1703961567&sr=8-3
But too expensive for my taste.
I would use an Arduino Nano connected to a laptop or computer.
Yes, you'd need a resistor (shunt) to convert current into voltage.
Program would just be a loop to monitor one of the Nano's A/D channels.
If the A/D value read exceeds the limit you set, output the value to the
Arduino Serial Monitor with the Nano to Laptop USB cable.
I think the Nano can do close to 4,000 samples per second (0.00025
seconds/sample) which I think would be sufficient to catch any event.
If you don't want it connected to a laptop, you'd need an SDCard shield
for the Nano so you can log the events to that.
I now see that US-sold Nano's apparently have gotten ridiculously
expensive ($25) at some sellers. But you can get them on eBay for $2
shipped if you're willing to wait for it to arrive from China. I also
see that some come with screw terminals if you don't like soldering.
Finn
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| Subject: | Data logger for DC volts and amps |
I know this is an English site, but similar devices must be available in
the US.
https://www.geminidataloggers.com/data-loggers
Look under =9CTinytag Instrumentation=9D
We use their temperature loggers at work, they are very reliable.
From: owner-aeroelectric-list-server@matronics.com
<owner-aeroelectric-list-server@matronics.com> On Behalf Of Jared Yates
Sent: Saturday, December 30, 2023 3:26 PM
Subject: AeroElectric-List: Data logger for DC volts and amps
Does anyone know of a device that will keep a log of current draw in the
.05-5A range, for 12-24 hours or so? I'm trying to troubleshoot an
intermittent battery drain but the usual multimeter requires me being
there and looking at it. The best alternative I have come up with so far
is to point a video camera at the multimeter but there must be a gadget
for this.
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| Subject: | Tailwind Electrical System Drawing and Power |
Analysis
Gerry,
In your initial post you asked for =9Ca good critique=9D of
your system, please take these comments in the supportive way they are
intended You are building a lot of redundancy (along with
complexity and cost) into your system that may not be required by the
purpose for which you intend to use the airplane. If you just want the
redundancy, and will tolerate the complexity and cost, then ignore what
I have written below.
Certified installations are required to operate for no less than 30
minutes following loss of the alternator. There are various rules
concerning how to calculate that endurance, but if your system can run
for 45 minutes on around 50% of the name plate battery capacity then you
are in about the right place. Your planned usage doesn=99t really
need two alternators and may not need 2 busbars. The things that will
cause you the most problems are engine reliability, maintaining control
of the airplane and then electrical reliability. We=99re not
really concerned with conventional engine reliability here. Fitting an
attitude indicator like a Garmin G5 (or similar with on-board sensors
and back-up battery) will provide *a lot* of redundancy. It may be you
could tolerate one bus bar and a POH list of stuff to turn off if the
alternator quits.
The assumption is if the electrical supply is lost you will always be
within no less than 30 minutes flying time of an acceptable alternate.
Actually, with aggressive load shedding, you will almost certainly be
able to burn all the fuel you have on board before the battery runs out
of juice, IMC, IFR or VMC. In a Tailwind you should be able to fly 50+
miles, and make an approach, in 30 minutes. In actuality you should be
able to fly for an hour or two.
Take a step back and look at the design of the whole electrical system.
Considering your intended usage do you really need all the complexity
you have designed into it? Will a single main battery, single
alternator, single busbar, battery backed-up AI system satisfy you
needs? What hazard is the 2 alternator, 3 busbar system you have drawn
intended to mitigate?
Peter
Battery capacity =93 many battery manufacturers are not entirely
helpful with their nameplate battery capacities with the makers of the
Odyssey series top of the list. The stated capacity is sometimes at the
10 or 20 hour rate, so the power provided if discharged over that time.
For our purposes the one hour, or even the 30 minute rate is what is
important. That number is usually less than the number quoted in the
sales literature. For a PC680 (nominally a 17AH battery) the one hour
rate is around 12Ah. Battery endurance calculations assume a battery
with 80% capacity (so shortly before replacement) with 10% charge used
on the ground, so take 72% of the one hour rate (8.6 Ah for a PC680).
=9CAircraft=9D battery makers are usually a little more
helpful. There are also guidelines on how quickly to assume the pilot
can carry out any loadshedding.
From: owner-aeroelectric-list-server@matronics.com
<owner-aeroelectric-list-server@matronics.com> On Behalf Of Gerry van
Dyk
Sent: Friday, December 29, 2023 7:57 PM
Subject: Re[5]: AeroElectric-List: Tailwind Electrical System Drawing
and Power Analysis
It will be for mainly VFR touring and vacation, IFR Training and
eventually IFR travel though VFR will be preferred over IFR. The VFR
weekend breakfast flyins and hambergers will likely be the bulk of
service. I want the personal rating and currency and the airplane's IFR
capability to be there the 2 or 3 time per year when it's likely to be
required. Like an annual pilgrimage to Osh. I don't want to be
stranded for weather that's overcast but otherwise fairly benign.
Does that answer the question?
Gerry
------ Original Message ------
>From "Peter Pengilly" <peter@sportingaero.com
<mailto:peter@sportingaero.com> >
To "Aeroelectric List (aeroelectric-list@matronics.com
<mailto:aeroelectric-list@matronics.com> )"
<aeroelectric-list@matronics.com
<mailto:aeroelectric-list@matronics.com> >
Date 2023-12-29 12:44:19 PM
Subject Re: Re[3]: AeroElectric-List: Tailwind Electrical System Drawing
and Power Analysis
Gerry, before looking at the details what are you planning to use the
airplane for? What do you want the system to do?
Long range IFR touring, medium range VFR/occasional IFR touring and VFR
hamburger runs, something else? Peter
On Fri, 29 Dec 2023, 19:27 Gerry van Dyk, <gerry.vandyk@eastlink.ca
<mailto:gerry.vandyk@eastlink.ca> > wrote:
Hello again all
Peter I'll follow-up here on those couple of points...
I've attached the latest revision to my architecture. Thinking about
what you've suggested, separating the main alternator to it's own
switch, I've done so, and it cleans up both the drawing and the
electrical system quite a bit. Effectively what we've done is separate
the "battery / alt / DC power" switch shown on the Z13/8 drawing into
two. I've got a keyed switch which I want for some basic theft
deterrence, and then the main alt switch.
In operation we'll turn on the main bus, which will mean the entire
panel will be up. The big consumers will of course be off, pitot heat,
exterior lighting, AP servos, boost fuel pump, and the radios will be in
passive receive mode. At this point we'd close the ebus / aux alt
switch and start the engine. Dynon says this will not bring down the
EFIS's so with the EMS operating we should see the aux alternator bump
the voltage, I'd flip the switch on and off if need be to see this
change. Satisfied that the aux alternator is operating we'll then bring
the main alternator online and turn the e-bus / aux alt switch off. Or
I may come around on leaving it on for normal operations.
For alternator-out condition: turn the e-bus / aux alt switch on, open
the main battery switch, dropping out the battery contactor and therefor
the main bus. If the main alt has failed or thrown the belt, it won't
matter much if we turn off the main alt switch or not.
What are your thoughts on this layout? I known I haven't used all your
suggestions, I hope you take no offense to it, I think some were moving
away from the original Z13/8 philosophy which I do rather agree with.
Best regards
Gerry
------ Original Message ------
>From "Gerry van Dyk" <gerry.vandyk@eastlink.ca
<mailto:gerry.vandyk@eastlink.ca> >
To aeroelectric-list@matronics.com
<mailto:aeroelectric-list@matronics.com>
Date 2023-12-29 8:12:00 AM
Subject Re[2]: AeroElectric-List: Tailwind Electrical System Drawing and
Power Analysis
Hi Peter, thanks for your thoughts.
Why do you want to switch the SD-8 alternator?
because it is shown on the original Z-13/8 drawing. I'm working from
rev T 1/07/14. Is there a later revision with this switch removed?
Why switch battery power to the bus twice?
As I mentioned, I want to start the engine on the E-bus. I need to
supply power to the starter, but leave the main bus un-powered, in order
to check the function of SD-8. Supplying starting power through the
E-bus seems impractical.
Use an externally regulated main alternator to avoid having to switch
the alternator output.
Yeah, I'm hamstringing myself a little bit here. I bought the AL
12-E160 alt several years ago, I don't have a spare couple thousand
dollars to buy another. I'll have to think about it better, but on the
face of it, having a separate regulator doesn't seem to change how the
alternator is controlled. Mr. Nuckolls has mentioned on many occasions
that we want to have definite control of the alternator output with a
switch in the cockpit. Z12/8 shows this switch in the center of the
drawing.
Provide a method to connect the battery directly to the bus. (I presume
your're talking about the main bus here.)
Perhaps I'm being foolish here. I'm placing an absolute requirement to
check the operation of the backup alternator at the beginning of every
flight. My life will depend on it should the main alternator fail.
With the main bus and main alternator connected directly to the battery
contactor they will be running at startup. As yet I don't see a way to
check the backup alternator operation with the main's running. I'd like
to do so without turning half the panel on-off-on during startup.
Do not use a diode in the feed to the essential bus.
This diode is called for by B&C on their installation drawing 504-500,
and they provide it in the kit. What would be the reason to remove it?
There are a number of services connected directly to the battery just
waiting to flatten it
Quite right, and this duplicates what's shown on Z13-8. They are a
couple of conveniences, loading the baggage compartment, charging a
phone etc, without having to turn on the battery master and it's
relatively large current draw. In building my panel, all switches will
be down=off, and they're all in two rows so visually obvious when left
on. I'll have to have a quick scan of the panel when leaving the
airplane, and if I flatten the battery by mistake, my fault.
If the voltage of the SD8 is set (say) 0.2v lower than the main
alternator it will not produce power if the main is on line. If the main
fails it takes up the load.
I presume you are making another case for removing the backup alt
switch. Again, it is called for on Z13/8, but your point is well taken.
For my liking you have too many relays between the battery and the bus
bar.
I absolutely agree, I haven't yet come up with an elegant solution to
check the backup alternator without cycling the avionics.
If you use an externally regulated main alternator then initially only
switch on the SD8 on start up. Then power up the main alternator
regulator and bring that on line.
I think we've covered this already. In order to start the engine I need
to switch on the battery contactor, which would also bring the main bus
and main alt online. I could move the starter wire to the always-hot
side of the battery contactor, so the mains are still inop, but with
that wire permanently hot, and 2 gauge wire at that, it violates the
idea of making the electrical system as inert as possible in a forced
landing. Again, I don't see the difference between an externally or
internally regulated alternator. The red wire to lead 1 on the alt
connector is the equivalent of the A wire on an external regulator, the
jumper is the same as one to the S wire, and the F wire is internal.
Peter, writing this is making me think about separating the main alt
control to a separate switch. Let me think that through a bit and I'll
report back later.
Install a switch that powers up the essential (or main) bus directly
from the battery, if the switch is a double pole use the second pole to
disable the starter.
Interesting, I'll think that out as well.
The large diode in the feed line to the essential bus will always drop
the voltage by an amount. The benefit is auto load shedding but do you
need that with 2 alternators? If you really want to shed the main bus
use a large switch and ensure there is a path to the essential bus
directly from the battery. I used to have a feed diode and would not use
one again.
Yes, I believe it is necessary. 8 amps will not power the entire panel,
so the load shedding is still valid. Incidentally, I discovered on the
SD-8 literature that a Lycoming will need to run at 2500 rpm to get the
full 8 amps out of the SD-8. it's looking like about 6.8 amps at 2300
rpm. Your suggestion will mean both main and E-bus need to be switched
on for normal operations. Bob has made note on many of his drawings
that "all buses are on when the main is on". I've had that in mind when
drawing this up. Having the E-bus switched on for normal ops means the
backup alternator is always running, though as you've suggested it can
be set lower than the main, and loaf along in the background. I need to
get my head around this idea.
A diode is very beneficial on the starter contactor.
That's a whoops, should have added it to the drawing, I'll get it on
there.
Having a low voltage waring that is independent of the EFIS is useful.
It is possible you will get immune to EFIS warnings
Yes, I do agree here. I was hoping the 'alt out light' function of the
main alternator would be a 'low voltage monitor' as B&C does on their
newer AVC regulator. After exchanging a couple of emails with Tim at
Plane Power, it indeed only sees the output within the alternator,
nothing outside. I've already got the Dynon EMS with all the engine
sensors, so it makes some sense to use what I've got. My thinking is if
it becomes annoying I can add the separate voltage monitoring system
after the fact. Tim at PP did mention that he regularly sees OBAM guys
using the EFIS for voltage monitoring, and all too often they've got
parameters set way too stringent, and get many nuisance warnings. As
yet I haven't investigated what parameters and settings I can work with,
so the ex4899258752836872026xb32b8cd5421647c9b8b804b1366feb00">
Thanks very much for the thoughts Peter. It's very useful to think
through the questions and comments.
Cheers
Gerry
------ Original Message ------
>From "Peter Pengilly" <peter@sportingaero.com
<mailto:peter@sportingaero.com> >
To aeroelectric-list@matronics.com
<mailto:aeroelectric-list@matronics.com>
Date 2023-12-29 2:11:12 AM
Subject RE: AeroElectric-List: Tailwind Electrical System Drawing and
Power Analysis
Why do you want to switch the SD-8 alternator?
Why switch battery power to the bus twice?
Use an externally regulated main alternator to avoid having to switch
the alternator output.
Provide a method to connect the battery directly to the bus.
Do not use a diode in the feed to the essential bus.
There are a number of services connected directly to the battery just
waiting to flatten it
If the voltage of the SD8 is set (say) 0.2v lower than the main
alternator it will not produce power if the main is on line. If the main
fails it takes up the load.
For my liking you have too many relays between the battery and the bus
bar.
If you use an externally regulated main alternator then initially only
switch on the SD8 on start up. Then power up the main alternator
regulator and bring that on line.
Install a switch that powers up the essential (or main) bus directly
from the battery, if the switch is a double pole use the second pole to
disable the starter.
The large diode in the feed line to the essential bus will always drop
the voltage by an amount. The benefit is auto load shedding but do you
need that with 2 alternators? If you really want to shed the main bus
use a large switch and ensure there is a path to the essential bus
directly from the battery. I used to have a feed diode and would not use
one again.
A diode is very beneficial on the starter contactor.
Having a low voltage waring that is independent of the EFIS is useful.
It is possible you will get immune to EFIS warnings
Peter
From: owner-aeroelectric-list-server@matronics.com
<mailto:owner-aeroelectric-list-server@matronics.com>
<owner-aeroelectric-list-server@matronics.com
<mailto:owner-aeroelectric-list-server@matronics.com> > On Behalf Of
Gerry van Dyk
Sent: Thursday, December 28, 2023 11:32 PM
<mailto:aeroelectric-list@matronics.com>
Subject: AeroElectric-List: Tailwind Electrical System Drawing and Power
Analysis
Hello again all
Well, I think I'm ready for a good critique on my proposed electrical
system for my Tailwind project. For the most part it's based on Z13/8,
we're using a Plane Power AL12-E160 primary alternator, and of course
the B&C SD-8 backup alternator. The E160 is internally regulated, and
also has an internal crowbar system and alt-out panel light output,
which I intend to use. The SD-8 has their older PMR1 regulator, so
we've got the external crowbar module and no voltage sensing. I've
drawn these items as shown on their respective install instructions call
for.
As I mentioned earlier, I intended to start the engine on the endurance
bus, and check the SD-8 operation during the startup procedure. I had
neglected to think about where the starter was going to get power from,
so the idea has forced an additional switch and relay (a rather robust
one at that) to run the main bus. The battery contactor would be closed
for startup, then the SD-8 operation checked and finally the main bus
would be brought up to begin normal operation.
I'm a little uneasy about this extra switching, as I know this group is
inclined toward fewer failure points, and with good reason. As I look
at the 'textbook' Z13/8 drawing, with my dual EFIS, IFR capable panel in
mind, it seems to me that a startup would bring the entire panel up with
the main bus, then with the engine running I'd have to close the E-bus
switch, open the battery contactor, dropping out half the instrument
panel. Then check the backup alternator operation, and finally reboot
the rest of the panel again. It just really feels rather clunky to me.
Bob, have I missed something with the original architecture concept? Is
there a way to check the backup alternator function while the main bus
is up and running? It would certainly help me simplify my system.
I'd appreciate if you good folks would give my drawing a good review.
Questions, comments and critiques are all welcome.
Thanks again
Gerry van Dyk
Tailwind C-GVDZ
Message 8
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| Subject: | Tailwind Electrical System Drawing and Power |
Analysis
Gerry,
I don=99t mind if you ignore all or anything I write! It is your
airplane after all.
I think you are overstating the situation by saying your life may depend
on the SD8 operating correctly. With aggressive load shedding, and
particularly in VMC, you will be able to fly for an hour or two on the
battery. Being able to turn off the battery contactor will remove
(around) 1A of draw from the system, so being able to connect the
battery to the bus bar (for low draw services, say up to 20A) can be
beneficial.
Peter
From: owner-aeroelectric-list-server@matronics.com
<owner-aeroelectric-list-server@matronics.com> On Behalf Of Gerry van
Dyk
Sent: Friday, December 29, 2023 7:18 PM
Subject: Re[3]: AeroElectric-List: Tailwind Electrical System Drawing
and Power Analysis
Hello again all
Peter I'll follow-up here on those couple of points...
I've attached the latest revision to my architecture. Thinking about
what you've suggested, separating the main alternator to it's own
switch, I've done so, and it cleans up both the drawing and the
electrical system quite a bit. Effectively what we've done is separate
the "battery / alt / DC power" switch shown on the Z13/8 drawing into
two. I've got a keyed switch which I want for some basic theft
deterrence, and then the main alt switch.
In operation we'll turn on the main bus, which will mean the entire
panel will be up. The big consumers will of course be off, pitot heat,
exterior lighting, AP servos, boost fuel pump, and the radios will be in
passive receive mode. At this point we'd close the ebus / aux alt
switch and start the engine. Dynon says this will not bring down the
EFIS's so with the EMS operating we should see the aux alternator bump
the voltage, I'd flip the switch on and off if need be to see this
change. Satisfied that the aux alternator is operating we'll then bring
the main alternator online and turn the e-bus / aux alt switch off. Or
I may come around on leaving it on for normal operations.
For alternator-out condition: turn the e-bus / aux alt switch on, open
the main battery switch, dropping out the battery contactor and therefor
the main bus. If the main alt has failed or thrown the belt, it won't
matter much if we turn off the main alt switch or not.
What are your thoughts on this layout? I known I haven't used all your
suggestions, I hope you take no offense to it, I think some were moving
away from the original Z13/8 philosophy which I do rather agree with.
Best regards
Gerry
------ Original Message ------
>From "Gerry van Dyk" <gerry.vandyk@eastlink.ca
<mailto:gerry.vandyk@eastlink.ca> >
To aeroelectric-list@matronics.com
<mailto:aeroelectric-list@matronics.com>
Date 2023-12-29 8:12:00 AM
Subject Re[2]: AeroElectric-List: Tailwind Electrical System Drawing and
Power Analysis
Hi Peter, thanks for your thoughts.
Why do you want to switch the SD-8 alternator?
because it is shown on the original Z-13/8 drawing. I'm working from
rev T 1/07/14. Is there a later revision with this switch removed?
Why switch battery power to the bus twice?
As I mentioned, I want to start the engine on the E-bus. I need to
supply power to the starter, but leave the main bus un-powered, in order
to check the function of SD-8. Supplying starting power through the
E-bus seems impractical.
Use an externally regulated main alternator to avoid having to switch
the alternator output.
Yeah, I'm hamstringing myself a little bit here. I bought the AL
12-E160 alt several years ago, I don't have a spare couple thousand
dollars to buy another. I'll have to think about it better, but on the
face of it, having a separate regulator doesn't seem to change how the
alternator is controlled. Mr. Nuckolls has mentioned on many occasions
that we want to have definite control of the alternator output with a
switch in the cockpit. Z12/8 shows this switch in the center of the
drawing.
Provide a method to connect the battery directly to the bus. (I presume
your're talking about the main bus here.)
Perhaps I'm being foolish here. I'm placing an absolute requirement to
check the operation of the backup alternator at the beginning of every
flight. My life will depend on it should the main alternator fail.
With the main bus and main alternator connected directly to the battery
contactor they will be running at startup. As yet I don't see a way to
check the backup alternator operation with the main's running. I'd like
to do so without turning half the panel on-off-on during startup.
Do not use a diode in the feed to the essential bus.
This diode is called for by B&C on their installation drawing 504-500,
and they provide it in the kit. What would be the reason to remove it?
There are a number of services connected directly to the battery just
waiting to flatten it
Quite right, and this duplicates what's shown on Z13-8. They are a
couple of conveniences, loading the baggage compartment, charging a
phone etc, without having to turn on the battery master and it's
relatively large current draw. In building my panel, all switches will
be down=off, and they're all in two rows so visually obvious when left
on. I'll have to have a quick scan of the panel when leaving the
airplane, and if I flatten the battery by mistake, my fault.
If the voltage of the SD8 is set (say) 0.2v lower than the main
alternator it will not produce power if the main is on line. If the main
fails it takes up the load.
I presume you are making another case for removing the backup alt
switch. Again, it is called for on Z13/8, but your point is well taken.
For my liking you have too many relays between the battery and the bus
bar.
I absolutely agree, I haven't yet come up with an elegant solution to
check the backup alternator without cycling the avionics.
If you use an externally regulated main alternator then initially only
switch on the SD8 on start up. Then power up the main alternator
regulator and bring that on line.
I think we've covered this already. In order to start the engine I need
to switch on the battery contactor, which would also bring the main bus
and main alt online. I could move the starter wire to the always-hot
side of the battery contactor, so the mains are still inop, but with
that wire permanently hot, and 2 gauge wire at that, it violates the
idea of making the electrical system as inert as possible in a forced
landing. Again, I don't see the difference between an externally or
internally regulated alternator. The red wire to lead 1 on the alt
connector is the equivalent of the A wire on an external regulator, the
jumper is the same as one to the S wire, and the F wire is internal.
Peter, writing this is making me think about separating the main alt
control to a separate switch. Let me think that through a bit and I'll
report back later.
Install a switch that powers up the essential (or main) bus directly
from the battery, if the switch is a double pole use the second pole to
disable the starter.
Interesting, I'll think that out as well.
The large diode in the feed line to the essential bus will always drop
the voltage by an amount. The benefit is auto load shedding but do you
need that with 2 alternators? If you really want to shed the main bus
use a large switch and ensure there is a path to the essential bus
directly from the battery. I used to have a feed diode and would not use
one again.
Yes, I believe it is necessary. 8 amps will not power the entire panel,
so the load shedding is still valid. Incidentally, I discovered on the
SD-8 literature that a Lycoming will need to run at 2500 rpm to get the
full 8 amps out of the SD-8. it's looking like about 6.8 amps at 2300
rpm. Your suggestion will mean both main and E-bus need to be switched
on for normal operations. Bob has made note on many of his drawings
that "all buses are on when the main is on". I've had that in mind when
drawing this up. Having the E-bus switched on for normal ops means the
backup alternator is always running, though as you've suggested it can
be set lower than the main, and loaf along in the background. I need to
get my head around this idea.
A diode is very beneficial on the starter contactor.
That's a whoops, should have added it to the drawing, I'll get it on
there.
Having a low voltage waring that is independent of the EFIS is useful.
It is possible you will get immune to EFIS warnings
Yes, I do agree here. I was hoping the 'alt out light' function of the
main alternator would be a 'low voltage monitor' as B&C does on their
newer AVC regulator. After exchanging a couple of emails with Tim at
Plane Power, it indeed only sees the output within the alternator,
nothing outside. I've already got the Dynon EMS with all the engine
sensors, so it makes some sense to use what I've got. My thinking is if
it becomes annoying I can add the separate voltage monitoring system
after the fact. Tim at PP did mention that he regularly sees OBAM guys
using the EFIS for voltage monitoring, and all too often they've got
parameters set way too stringent, and get many nuisance warnings. As
yet I haven't investigated what parameters and settings I can work with,
so the external LV warning is always on the table.
Thanks very much for the thoughts Peter. It's very useful to think
through the questions and comments.
Cheers
Gerry
------ Original Message ------
>From "Peter Pengilly" <peter@sportingaero.com
<mailto:peter@sportingaero.com> >
To aeroelectric-list@matronics.com
<mailto:aeroelectric-list@matronics.com>
Date 2023-12-29 2:11:12 AM
Subject RE: AeroElectric-List: Tailwind Electrical System Drawing and
Power Analysis
Why do you want to switch the SD-8 alternator?
Why switch battery power to the bus twice?
Use an externally regulated main alternator to avoid having to switch
the alternator output.
Provide a method to connect the battery directly to the bus.
Do not use a diode in the feed to the essential bus.
There are a number of services connected directly to the battery just
waiting to flatten it
If the voltage of the SD8 is set (say) 0.2v lower than the main
alternator it will not produce power if the main is on line. If the main
fails it takes up the load.
For my liking you have too many relays between the battery and the bus
bar.
If you use an externally regulated main alternator then initially only
switch on the SD8 on start up. Then power up the main alternator
regulator and bring that on line.
Install a switch that powers up the essential (or main) bus directly
from the battery, if the switch is a double pole use the second pole to
disable the starter.
The large diode in the feed line to the essential bus will always drop
the voltage by an amount. The benefit is auto load shedding but do you
need that with 2 alternators? If you really want to shed the main bus
use a large switch and ensure there is a path to the essential bus
directly from the battery. I used to have a feed diode and would not use
one again.
A diode is very beneficial on the starter contactor.
Having a low voltage waring that is independent of the EFIS is useful.
It is possible you will get immune to EFIS warnings
Peter
From: owner-aeroelectric-list-server@matronics.com
<mailto:owner-aeroelectric-list-server@matronics.com>
<owner-aeroelectric-list-server@matronics.com
<mailto:owner-aeroelectric-list-server@matronics.com> > On Behalf Of
Gerry van Dyk
Sent: Thursday, December 28, 2023 11:32 PM
<mailto:aeroelectric-list@matronics.com>
Subject: AeroElectric-List: Tailwind Electrical System Drawing and Power
Analysis
Hello again all
Well, I think I'm ready for a good critique on my proposed electrical
system for my Tailwind project. For the most part it's based on Z13/8,
we're using a Plane Power AL12-E160 primary alternator, and of course
the B&C SD-8 backup alternator. The E160 is internally regulated, and
also has an internal crowbar system and alt-out panel light output,
which I intend to use. The SD-8 has their older PMR1 regulator, so
we've got the external crowbar module and no voltage sensing. I've
drawn these items as shown on their respective install instructions call
for.
As I mentioned earlier, I intended to start the engine on the endurance
bus, and check the SD-8 operation during the startup procedure. I had
neglected to think about where the starter was going to get power from,
so the idea has forced an additional switch and relay (a rather robust
one at that) to run the main bus. The battery contactor would be closed
for startup, then the SD-8 operation checked and finally the main bus
would be brought up to begin normal operation.
I'm a little uneasy about this extra switching, as I know this group is
inclined toward fewer failure points, and with good reason. As I look
at the 'textbook' Z13/8 drawing, with my dual EFIS, IFR capable panel in
mind, it seems to me that a startup would bring the entire panel up with
the main bus, then with the engine running I'd have to close the E-bus
switch, open the battery contactor, dropping out half the instrument
panel. Then check the backup alternator operation, and finally reboot
the rest of the panel again. It just really feels rather clunky to me.
Bob, have I missed something with the original architecture concept? Is
there a way to check the backup alternator function while the main bus
is up and running? It would certainly help me simplify my system.
I'd appreciate if you good folks would give my drawing a good review.
Questions, comments and critiques are all welcome.
Thanks again
Gerry van Dyk
Tailwind C-GVDZ
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| Subject: | Tailwind Electrical System Drawing and Power |
Analysis
No worries Peter, all fair points.
A little background on myself for you. I am an engineer and draftsman
by trade. That along with a Dutch heritage, it is absolutely fair to
say I AM STUBBORN! ;^)
For the last 10 years or so while I've been building I've been following
along the AE list and reading the AEC. Mr Nuckolls has been
recommending Z13/8 as the most bang for the buck, and I certainly agree
with the idea. Along the way I've been collecting all the parts to
build the system. The two alternators have been bolted to the engine
for a couple of years.
Quick segue for a moment. I've always owned vehicles with 4 seats. For
most of my life I've owned pickup trucks. It is shocking how rarely I
carry even 1 passenger, and 4 people is more rare than a blue moon.
Even carrying something in the back of the truck isn't that common, yet
I, like many other people, think nothing of selecting such a vehicle,
just for the utility when it comes up.
Back on point...
I've had some friends have issues with Transport Canada getting the 'no
IFR' clause removed from the limitations on their flight permits.
Though the rules are murky, transport usually cites redundancy of
systems. I've heard of one occasion where a guy needed to put an
altitude encoder into his airplane, so the altitude signal went to the
encoder, was converted to grey code and then passed on to the efis which
had to decode it back to the signal it was expecting in the first place.
The inspected remembered some 30 year old guidance document from
Transport that this was required, and weather or not the thing was still
in force, (it was most certainly obsolete) when the inspector writes it
up, we must comply or be denied. Actually that fellow installed the
encoder, showed the inspector for the signoff, then promptly removed it
before going flying. These are the things we must do to satisfy
bureaucrats all over the world. In my mind, being able to show a system
with two approach certified VORs, one approach certified GPS, plus a
triple redundant power supply should make the IFR signoff relatively
easy. And because I've been studying the drawings for so long, it does
indeed give me comfort in the system.
As for acutally using the airplane for IFR, I indeed class it the same
as owning a four seat pickup truck. Rarely ever used, but there when I
need it. And to be sure, I still need to earn the rating, and keep
current, so I suspect I'll fly under the hood more often than I've
carried lumber in the truck. ;^)
As for the extra bus, the battery bus is really only there for the
convenience of charging a phone now and then, and lighting the baggabe
bay when loading up in the wee hours of the morning before a trip. I
could easily function without it, but I suspect I'll use it about as
often as I fly in actual IMC. Yeah, it's a bit of overkill, but it's
what I've been working towards for years, so changing the system,
pulling parts off the engine, and ignoring the parts already on the
shelf would really be against my nature. ;^)
Thanks for the thoughts Peter. It is wise to give some sober thought to
what the hell we're doing once in a while. For what it's worth, I've
got a rebuild project on a Mong Sport biplane in the wings. It'll have
a simple 8 amp alternator, battery and starter circuit, and a small efis
with a couple of analog instruments, because I have no delusions of
flying that airplane for anything more than an afternoon of giggles.
;^)
Best regards
Gerry
------ Original Message ------
>From "Peter Pengilly" <Peter@sportingaero.com>
To aeroelectric-list@matronics.com
Date 2023-12-30 3:35:32 PM
Subject RE: Re[5]: AeroElectric-List: Tailwind Electrical System Drawing
and Power Analysis
>Gerry,
>
>
>In your initial post you asked for =9Ca good critique=9D of yo
ur system,
>please take these comments in the supportive way they are intended
You
>are building a lot of redundancy (along with complexity and cost) into
>your system that may not be required by the purpose for which you
>intend to use the airplane. If you just want the redundancy, and will
>tolerate the complexity and cost, then ignore what I have written
>below.
>
>
>Certified installations are required to operate for no less than 30
>minutes following loss of the alternator. There are various rules
>concerning how to calculate that endurance, but if your system can run
>for 45 minutes on around 50% of the name plate battery capacity then
>you are in about the right place. Your planned usage doesn=99t reall
y
>need two alternators and may not need 2 busbars. The things that will
>cause you the most problems are engine reliability, maintaining control
>of the airplane and then electrical reliability. We=99re not really
>concerned with conventional engine reliability here. Fitting an
>attitude indicator like a Garmin G5 (or similar with on-board sensors
>and back-up battery) will provide *a lot* of redundancy. It may be you
>could tolerate one bus bar and a POH list of stuff to turn off if the
>alternator quits.
>
>
>The assumption is if the electrical supply is lost you will always be
>within no less than 30 minutes flying time of an acceptable alternate.
>Actually, with aggressive load shedding, you will almost certainly be
>able to burn all the fuel you have on board before the battery runs out
>of juice, IMC, IFR or VMC. In a Tailwind you should be able to fly 50+
>miles, and make an approach, in 30 minutes. In actuality you should be
>able to fly for an hour or two.
>
>
>Take a step back and look at the design of the whole electrical system.
>Considering your intended usage do you really need all the complexity
>you have designed into it? Will a single main battery, single
>alternator, single busbar, battery backed-up AI system satisfy you
>needs? What hazard is the 2 alternator, 3 busbar system you have drawn
>intended to mitigate?
>
>
>Peter
>
>
>Battery capacity =93 many battery manufacturers are not entirely hel
pful
>with their nameplate battery capacities with the makers of the Odyssey
>series top of the list. The stated capacity is sometimes at the 10 or
>20 hour rate, so the power provided if discharged over that time. For
>our purposes the one hour, or even the 30 minute rate is what is
>important. That number is usually less than the number quoted in the
>sales literature. For a PC680 (nominally a 17AH battery) the one hour
>rate is around 12Ah. Battery endurance calculations assume a battery
>with 80% capacity (so shortly before replacement) with 10% charge used
>on the ground, so take 72% of the one hour rate (8.6 Ah for a PC680).
>=9CAircraft=9D battery makers are usually a little more helpfu
l. There are
>also guidelines on how quickly to assume the pilot can carry out any
>loadshedding.
>
>
>From:owner-aeroelectric-list-server@matronics.com
><owner-aeroelectric-list-server@matronics.com> On Behalf Of Gerry van
>Dyk
>Sent: Friday, December 29, 2023 7:57 PM
>To:aeroelectric-list@matronics.com
>Subject: Re[5]: AeroElectric-List: Tailwind Electrical System Drawing
>and Power Analysis
>
>
>It will be for mainly VFR touring and vacation, IFR Training and
>eventually IFR travel though VFR will be preferred over IFR. The VFR
>weekend breakfast flyins and hambergers will likely be the bulk of
>service. I want the personal rating and currency and the airplane's
>IFR capability to be there the 2 or 3 time per year when it's likely to
>be required. Like an annual pilgrimage to Osh. I don't want to be
>stranded for weather that's overcast but otherwise fairly benign.
>
>
>Does that answer the question?
>
>Gerry
>
>
>------ Original Message ------
>
>From "Peter Pengilly" <peter@sportingaero.com>
>
>To "Aeroelectric List (aeroelectric-list@matronics.com)"
><aeroelectric-list@matronics.com>
>
>Date 2023-12-29 12:44:19 PM
>
>Subject Re: Re[3]: AeroElectric-List: Tailwind Electrical System
>Drawing and Power Analysis
>
>
>>Gerry, before looking at the details what are you planning to use the
>>airplane for? What do you want the system to do?
>>
>>Long range IFR touring, medium range VFR/occasional IFR touring and
>>VFR hamburger runs, something else? Peter
>>
>>
>>
>>On Fri, 29 Dec 2023, 19:27 Gerry van Dyk, <gerry.vandyk@eastlink.ca>
>>wrote:
>>
>>>Hello again all
>>>
>>>Peter I'll follow-up here on those couple of points...
>>>
>>>
>>>
>>>I've attached the latest revision to my architecture. Thinking about
>>>what you've suggested, separating the main alternator to it's own
>>>switch, I've done so, and it cleans up both the drawing and the
>>>electrical system quite a bit. Effectively what we've done is
>>>separate the "battery / alt / DC power" switch shown on the Z13/8
>>>drawing into two. I've got a keyed switch which I want for some
>>>basic theft deterrence, and then the main alt switch.
>>>
>>>
>>>
>>>In operation we'll turn on the main bus, which will mean the entire
>>>panel will be up. The big consumers will of course be off, pitot
>>>heat, exterior lighting, AP servos, boost fuel pump, and the radios
>>>will be in passive receive mode. At this point we'd close the ebus /
>>>aux alt switch and start the engine. Dynon says this will not bring
>>>down the EFIS's so with the EMS operating we should see the aux
>>>alternator bump the voltage, I'd flip the switch on and off if need
>>>be to see this change. Satisfied that the aux alternator is
>>>operating we'll then bring the main alternator online and turn the
>>>e-bus / aux alt switch off. Or I may come around on leaving it on
>>>for normal operations.
>>>
>>>
>>>
>>>For alternator-out condition: turn the e-bus / aux alt switch on,
>>>open the main battery switch, dropping out the battery contactor and
>>>therefor the main bus. If the main alt has failed or thrown the
>>>belt, it won't matter much if we turn off the main alt switch or not.
>>>
>>>
>>>
>>>What are your thoughts on this layout? I known I haven't used all
>>>your suggestions, I hope you take no offense to it, I think some were
>>>moving away from the original Z13/8 philosophy which I do rather
>>>agree with.
>>>
>>>
>>>
>>>Best regards
>>>
>>>Gerry
>>>
>>>
>>>
>>>
>>>
>>>------ Original Message ------
>>>
>>>From "Gerry van Dyk" <gerry.vandyk@eastlink.ca>
>>>
>>>To aeroelectric-list@matronics.com
>>>
>>>Date 2023-12-29 8:12:00 AM
>>>
>>>Subject Re[2]: AeroElectric-List: Tailwind Electrical System Drawing
>>>and Power Analysis
>>>
>>>
>>>
>>>>Hi Peter, thanks for your thoughts.
>>>>
>>>>Why do you want to switch the SD-8 alternator?
>>>>
>>>>because it is shown on the original Z-13/8 drawing. I'm working
>>>>from rev T 1/07/14. Is there a later revision with this switch
>>>>removed?
>>>>
>>>>Why switch battery power to the bus twice?
>>>>
>>>>As I mentioned, I want to start the engine on the E-bus. I need to
>>>>supply power to the starter, but leave the main bus un-powered, in
>>>>order to check the function of SD-8. Supplying starting power
>>>>through the E-bus seems impractical.
>>>>
>>>>Use an externally regulated main alternator to avoid having to
>>>>switch the alternator output.
>>>>
>>>>Yeah, I'm hamstringing myself a little bit here. I bought the AL
>>>>12-E160 alt several years ago, I don't have a spare couple thousand
>>>>dollars to buy another. I'll have to think about it better, but on
>>>>the face of it, having a separate regulator doesn't seem to change
>>>>how the alternator is controlled. Mr. Nuckolls has mentioned on
>>>>many occasions that we want to have definite control of the
>>>>alternator output with a switch in the cockpit. Z12/8 shows this
>>>>switch in the center of the drawing.
>>>>
>>>>Provide a method to connect the battery directly to the bus. (I
>>>>presume your're talking about the main bus here.)
>>>>
>>>>Perhaps I'm being foolish here. I'm placing an absolute requirement
>>>>to check the operation of the backup alternator at the beginning of
>>>>every flight. My life will depend on it should the main alternator
>>>>fail. With the main bus and main alternator connected directly to
>>>>the battery contactor they will be running at startup. As yet I
>>>>don't see a way to check the backup alternator operation with the
>>>>main's running. I'd like to do so without turning half the panel
>>>>on-off-on during startup.
>>>>
>>>>Do not use a diode in the feed to the essential bus.
>>>>
>>>>This diode is called for by B&C on their installation drawing
>>>>504-500, and they provide it in the kit. What would be the reason
>>>>to remove it?
>>>>
>>>>There are a number of services connected directly to the battery
>>>>just waiting to flatten it
>>>>
>>>>Quite right, and this duplicates what's shown on Z13-8. They are a
>>>>couple of conveniences, loading the baggage compartment, charging a
>>>>phone etc, without having to turn on the battery master and it's
>>>>relatively large current draw. In building my panel, all switches
>>>>will be down=off, and they're all in two rows so visually obvious
>>>>when left on. I'll have to have a quick scan of the panel when
>>>>leaving the airplane, and if I flatten the battery by mistake, my
>>>>fault.
>>>>
>>>>If the voltage of the SD8 is set (say) 0.2v lower than the main
>>>>alternator it will not produce power if the main is on line. If the
>>>>main fails it takes up the load.
>>>>
>>>>I presume you are making another case for removing the backup alt
>>>>switch. Again, it is called for on Z13/8, but your point is well
>>>>taken.
>>>>
>>>>For my liking you have too many relays between the battery and the
>>>>bus bar.
>>>>
>>>>I absolutely agree, I haven't yet come up with an elegant solution
>>>>to check the backup alternator without cycling the avionics.
>>>>
>>>>If you use an externally regulated main alternator then initially
>>>>only switch on the SD8 on start up. Then power up the main
>>>>alternator regulator and bring that on line.
>>>>
>>>>I think we've covered this already. In order to start the engine I
>>>>need to switch on the battery contactor, which would also bring the
>>>>main bus and main alt online. I could move the starter wire to the
>>>>always-hot side of the battery contactor, so the mains are still
>>>>inop, but with that wire permanently hot, and 2 gauge wire at that,
>>>>it violates the idea of making the electrical system as inert as
>>>>possible in a forced landing. Again, I don't see the difference
>>>>between an externally or internally regulated alternator. The red
>>>>wire to lead 1 on the alt connector is the equivalent of the A wire
>>>>on an external regulator, the jumper is the same as one to the S
>>>>wire, and the F wire is internal.
>>>>
>>>>Peter, writing this is making me think about separating the main alt
>>>>control to a separate switch. Let me think that through a bit and
>>>>I'll report back later.
>>>>
>>>>Install a switch that powers up the essential (or main) bus directly
>>>>from the battery, if the switch is a double pole use the second pole
>>>>to disable the starter.
>>>>
>>>>Interesting, I'll think that out as well.
>>>>
>>>>The large diode in the feed line to the essential bus will always
>>>>drop the voltage by an amount. The benefit is auto load shedding but
>>>>do you need that with 2 alternators? If you really want to shed the
>>>>main bus use a large switch and ensure there is a path to the
>>>>essential bus directly from the battery. I used to have a feed diode
>>>>and would not use one again.
>>>>
>>>>Yes, I believe it is necessary. 8 amps will not power the entire
>>>>panel, so the load shedding is still valid. Incidentally, I
>>>>discovered on the SD-8 literature that a Lycoming will need to run
>>>>at 2500 rpm to get the full 8 amps out of the SD-8. it's looking
>>>>like about 6.8 amps at 2300 rpm. Your suggestion will mean both
>>>>main and E-bus need to be switched on for normal operations. Bob
>>>>has made note on many of his drawings that "all buses are on when
>>>>the main is on". I've had that in mind when drawing this up.
>>>>Having the E-bus switched on for normal ops means the backup
>>>>alternator is always running, though as you've suggested it can be
>>>>set lower than the main, and loaf along in the background. I need
>>>>to get my head around this idea.
>>>>
>>>>A diode is very beneficial on the starter contactor.
>>>>
>>>>That's a whoops, should have added it to the drawing, I'll get it on
>>>>there.
>>>>
>>>>Having a low voltage waring that is independent of the EFIS is
>>>>useful. It is possible you will get immune to EFIS warnings
>>>>
>>>>Yes, I do agree here. I was hoping the 'alt out light' function of
>>>>the main alternator would be a 'low voltage monitor' as B&C does on
>>>>their newer AVC regulator. After exchanging a couple of emails with
>>>>Tim at Plane Power, it indeed only sees the output within the
>>>>alternator, nothing outside. I've already got the Dynon EMS with
>>>>all the engine sensors, so it makes some sense to use what I've got.
>>>> My thinking is if it becomes annoying I can add the separate
>>>>voltage monitoring system after the fact. Tim at PP did mention
>>>>that he regularly sees OBAM guys using the EFIS for voltage
>>>>monitoring, and all too often they've got parameters set way too
>>>>stringent, and get many nuisance warnings. As yet I haven't
>>>>investigated what parameters and settings I can work with, so the
>>>>ex4899258752836872026xb32b8cd5421647c9b8b804b1366feb00">
>>>>
>>>>Thanks very much for the thoughts Peter. It's very useful to think
>>>>through the questions and comments.
>>>>
>>>>
>>>>
>>>>Cheers
>>>>
>>>>Gerry
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>------ Original Message ------
>>>>
>>>>From "Peter Pengilly" <peter@sportingaero.com>
>>>>
>>>>To aeroelectric-list@matronics.com
>>>>
>>>>Date 2023-12-29 2:11:12 AM
>>>>
>>>>Subject RE: AeroElectric-List: Tailwind Electrical System Drawing
>>>>and Power Analysis
>>>>
>>>>
>>>>
>>>>>Why do you want to switch the SD-8 alternator?
>>>>>
>>>>>Why switch battery power to the bus twice?
>>>>>
>>>>>Use an externally regulated main alternator to avoid having to
>>>>>switch the alternator output.
>>>>>
>>>>>Provide a method to connect the battery directly to the bus.
>>>>>
>>>>>Do not use a diode in the feed to the essential bus.
>>>>>
>>>>>There are a number of services connected directly to the battery
>>>>>just waiting to flatten it
>>>>>
>>>>>
>>>>>
>>>>>If the voltage of the SD8 is set (say) 0.2v lower than the main
>>>>>alternator it will not produce power if the main is on line. If the
>>>>>main fails it takes up the load.
>>>>>
>>>>>For my liking you have too many relays between the battery and the
>>>>>bus bar.
>>>>>
>>>>>If you use an externally regulated main alternator then initially
>>>>>only switch on the SD8 on start up. Then power up the main
>>>>>alternator regulator and bring that on line.
>>>>>
>>>>>Install a switch that powers up the essential (or main) bus
>>>>>directly from the battery, if the switch is a double pole use the
>>>>>second pole to disable the starter.
>>>>>
>>>>>The large diode in the feed line to the essential bus will always
>>>>>drop the voltage by an amount. The benefit is auto load shedding
>>>>>but do you need that with 2 alternators? If you really want to shed
>>>>>the main bus use a large switch and ensure there is a path to the
>>>>>essential bus directly from the battery. I used to have a feed
>>>>>diode and would not use one again.
>>>>>
>>>>>A diode is very beneficial on the starter contactor.
>>>>>
>>>>>Having a low voltage waring that is independent of the EFIS is
>>>>>useful. It is possible you will get immune to EFIS warnings
>>>>>
>>>>>
>>>>>
>>>>>Peter
>>>>>
>>>>>
>>>>>
>>>>>From:owner-aeroelectric-list-server@matronics.com
>>>>><owner-aeroelectric-list-server@matronics.com> On Behalf Of Gerry
>>>>>van Dyk
>>>>>Sent: Thursday, December 28, 2023 11:32 PM
>>>>>To:aeroelectric-list@matronics.com
>>>>>Subject: AeroElectric-List: Tailwind Electrical System Drawing and
>>>>>Power Analysis
>>>>>
>>>>>
>>>>>
>>>>>Hello again all
>>>>>
>>>>>Well, I think I'm ready for a good critique on my proposed
>>>>>electrical system for my Tailwind project. For the most part it's
>>>>>based on Z13/8, we're using a Plane Power AL12-E160 primary
>>>>>alternator, and of course the B&C SD-8 backup alternator. The E160
>>>>>is internally regulated, and also has an internal crowbar system
>>>>>and alt-out panel light output, which I intend to use. The SD-8
>>>>>has their older PMR1 regulator, so we've got the external crowbar
>>>>>module and no voltage sensing. I've drawn these items as shown on
>>>>>their respective install instructions call for.
>>>>>
>>>>>
>>>>>
>>>>>As I mentioned earlier, I intended to start the engine on the
>>>>>endurance bus, and check the SD-8 operation during the startup
>>>>>procedure. I had neglected to think about where the starter was
>>>>>going to get power from, so the idea has forced an additional
>>>>>switch and relay (a rather robust one at that) to run the main bus.
>>>>> The battery contactor would be closed for startup, then the SD-8
>>>>>operation checked and finally the main bus would be brought up to
>>>>>begin normal operation.
>>>>>
>>>>>
>>>>>
>>>>>I'm a little uneasy about this extra switching, as I know this
>>>>>group is inclined toward fewer failure points, and with good
>>>>>reason. As I look at the 'textbook' Z13/8 drawing, with my dual
>>>>>EFIS, IFR capable panel in mind, it seems to me that a startup
>>>>>would bring the entire panel up with the main bus, then with the
>>>>>engine running I'd have to close the E-bus switch, open the battery
>>>>>contactor, dropping out half the instrument panel. Then check the
>>>>>backup alternator operation, and finally reboot the rest of the
>>>>>panel again. It just really feels rather clunky to me.
>>>>>
>>>>>
>>>>>
>>>>>Bob, have I missed something with the original architecture
>>>>>concept? Is there a way to check the backup alternator function
>>>>>while the main bus is up and running? It would certainly help me
>>>>>simplify my system.
>>>>>
>>>>>
>>>>>
>>>>>I'd appreciate if you good folks would give my drawing a good
>>>>>review. Questions, comments and critiques are all welcome.
>>>>>
>>>>>
>>>>>
>>>>>Thanks again
>>>>>
>>>>>Gerry van Dyk
>>>>>
>>>>>Tailwind C-GVDZ
>>>>>
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| Subject: | Tailwind Electrical System Drawing and Power |
Analysis
Yeah, I'm obviously not above a little healthy hyperbole now and then.
;^)
Gerry
------ Original Message ------
>From "Peter Pengilly" <Peter@sportingaero.com>
To aeroelectric-list@matronics.com
Date 2023-12-30 3:47:38 PM
Subject RE: Re[3]: AeroElectric-List: Tailwind Electrical System Drawing
and Power Analysis
>Gerry,
>
>
>I don=99t mind if you ignore all or anything I write! It is your air
plane
>after all.
>
>
>I think you are overstating the situation by saying your life may
>depend on the SD8 operating correctly. With aggressive load shedding,
>and particularly in VMC, you will be able to fly for an hour or two on
>the battery. Being able to turn off the battery contactor will remove
>(around) 1A of draw from the system, so being able to connect the
>battery to the bus bar (for low draw services, say up to 20A) can be
>beneficial.
>
>
>Peter
>
>
>From:owner-aeroelectric-list-server@matronics.com
><owner-aeroelectric-list-server@matronics.com> On Behalf Of Gerry van
>Dyk
>Sent: Friday, December 29, 2023 7:18 PM
>To:aeroelectric-list@matronics.com
>Subject: Re[3]: AeroElectric-List: Tailwind Electrical System Drawing
>and Power Analysis
>
>
>Hello again all
>
>Peter I'll follow-up here on those couple of points...
>
>
>I've attached the latest revision to my architecture. Thinking about
>what you've suggested, separating the main alternator to it's own
>switch, I've done so, and it cleans up both the drawing and the
>electrical system quite a bit. Effectively what we've done is separate
>the "battery / alt / DC power" switch shown on the Z13/8 drawing into
>two. I've got a keyed switch which I want for some basic theft
>deterrence, and then the main alt switch.
>
>
>In operation we'll turn on the main bus, which will mean the entire
>panel will be up. The big consumers will of course be off, pitot heat,
>exterior lighting, AP servos, boost fuel pump, and the radios will be
>in passive receive mode. At this point we'd close the ebus / aux alt
>switch and start the engine. Dynon says this will not bring down the
>EFIS's so with the EMS operating we should see the aux alternator bump
>the voltage, I'd flip the switch on and off if need be to see this
>change. Satisfied that the aux alternator is operating we'll then
>bring the main alternator online and turn the e-bus / aux alt switch
>off. Or I may come around on leaving it on for normal operations.
>
>
>For alternator-out condition: turn the e-bus / aux alt switch on, open
>the main battery switch, dropping out the battery contactor and
>therefor the main bus. If the main alt has failed or thrown the belt,
>it won't matter much if we turn off the main alt switch or not.
>
>
>What are your thoughts on this layout? I known I haven't used all your
>suggestions, I hope you take no offense to it, I think some were moving
>away from the original Z13/8 philosophy which I do rather agree with.
>
>
>Best regards
>
>Gerry
>
>
>------ Original Message ------
>
>From "Gerry van Dyk" <gerry.vandyk@eastlink.ca>
>
>To aeroelectric-list@matronics.com
>
>Date 2023-12-29 8:12:00 AM
>
>Subject Re[2]: AeroElectric-List: Tailwind Electrical System Drawing
>and Power Analysis
>
>
>>Hi Peter, thanks for your thoughts.
>>
>>Why do you want to switch the SD-8 alternator?
>>
>>because it is shown on the original Z-13/8 drawing. I'm working from
>>rev T 1/07/14. Is there a later revision with this switch removed?
>>
>>Why switch battery power to the bus twice?
>>
>>As I mentioned, I want to start the engine on the E-bus. I need to
>>supply power to the starter, but leave the main bus un-powered, in
>>order to check the function of SD-8. Supplying starting power through
>>the E-bus seems impractical.
>>
>>Use an externally regulated main alternator to avoid having to switch
>>the alternator output.
>>
>>Yeah, I'm hamstringing myself a little bit here. I bought the AL
>>12-E160 alt several years ago, I don't have a spare couple thousand
>>dollars to buy another. I'll have to think about it better, but on
>>the face of it, having a separate regulator doesn't seem to change how
>>the alternator is controlled. Mr. Nuckolls has mentioned on many
>>occasions that we want to have definite control of the alternator
>>output with a switch in the cockpit. Z12/8 shows this switch in the
>>center of the drawing.
>>
>>Provide a method to connect the battery directly to the bus. (I
>>presume your're talking about the main bus here.)
>>
>>Perhaps I'm being foolish here. I'm placing an absolute requirement
>>to check the operation of the backup alternator at the beginning of
>>every flight. My life will depend on it should the main alternator
>>fail. With the main bus and main alternator connected directly to the
>>battery contactor they will be running at startup. As yet I don't see
>>a way to check the backup alternator operation with the main's
>>running. I'd like to do so without turning half the panel on-off-on
>>during startup.
>>
>>Do not use a diode in the feed to the essential bus.
>>
>>This diode is called for by B&C on their installation drawing 504-500,
>>and they provide it in the kit. What would be the reason to remove
>>it?
>>
>>There are a number of services connected directly to the battery just
>>waiting to flatten it
>>
>>Quite right, and this duplicates what's shown on Z13-8. They are a
>>couple of conveniences, loading the baggage compartment, charging a
>>phone etc, without having to turn on the battery master and it's
>>relatively large current draw. In building my panel, all switches
>>will be down=off, and they're all in two rows so visually obvious when
>>left on. I'll have to have a quick scan of the panel when leaving the
>>airplane, and if I flatten the battery by mistake, my fault.
>>
>>If the voltage of the SD8 is set (say) 0.2v lower than the main
>>alternator it will not produce power if the main is on line. If the
>>main fails it takes up the load.
>>
>>I presume you are making another case for removing the backup alt
>>switch. Again, it is called for on Z13/8, but your point is well
>>taken.
>>
>>For my liking you have too many relays between the battery and the bus
>>bar.
>>
>>I absolutely agree, I haven't yet come up with an elegant solution to
>>check the backup alternator without cycling the avionics.
>>
>>If you use an externally regulated main alternator then initially only
>>switch on the SD8 on start up. Then power up the main alternator
>>regulator and bring that on line.
>>
>>I think we've covered this already. In order to start the engine I
>>need to switch on the battery contactor, which would also bring the
>>main bus and main alt online. I could move the starter wire to the
>>always-hot side of the battery contactor, so the mains are still inop,
>>but with that wire permanently hot, and 2 gauge wire at that, it
>>violates the idea of making the electrical system as inert as possible
>>in a forced landing. Again, I don't see the difference between an
>>externally or internally regulated alternator. The red wire to lead 1
>>on the alt connector is the equivalent of the A wire on an external
>>regulator, the jumper is the same as one to the S wire, and the F wire
>>is internal.
>>
>>Peter, writing this is making me think about separating the main alt
>>control to a separate switch. Let me think that through a bit and
>>I'll report back later.
>>
>>Install a switch that powers up the essential (or main) bus directly
>>from the battery, if the switch is a double pole use the second pole
>>to disable the starter.
>>
>>Interesting, I'll think that out as well.
>>
>>The large diode in the feed line to the essential bus will always drop
>>the voltage by an amount. The benefit is auto load shedding but do you
>>need that with 2 alternators? If you really want to shed the main bus
>>use a large switch and ensure there is a path to the essential bus
>>directly from the battery. I used to have a feed diode and would not
>>use one again.
>>
>>Yes, I believe it is necessary. 8 amps will not power the entire
>>panel, so the load shedding is still valid. Incidentally, I
>>discovered on the SD-8 literature that a Lycoming will need to run at
>>2500 rpm to get the full 8 amps out of the SD-8. it's looking like
>>about 6.8 amps at 2300 rpm. Your suggestion will mean both main and
>>E-bus need to be switched on for normal operations. Bob has made note
>>on many of his drawings that "all buses are on when the main is on".
>>I've had that in mind when drawing this up. Having the E-bus switched
>>on for normal ops means the backup alternator is always running,
>>though as you've suggested it can be set lower than the main, and loaf
>>along in the background. I need to get my head around this idea.
>>
>>A diode is very beneficial on the starter contactor.
>>
>>That's a whoops, should have added it to the drawing, I'll get it on
>>there.
>>
>>Having a low voltage waring that is independent of the EFIS is useful.
>>It is possible you will get immune to EFIS warnings
>>
>>Yes, I do agree here. I was hoping the 'alt out light' function of
>>the main alternator would be a 'low voltage monitor' as B&C does on
>>their newer AVC regulator. After exchanging a couple of emails with
>>Tim at Plane Power, it indeed only sees the output within the
>>alternator, nothing outside. I've already got the Dynon EMS with all
>>the engine sensors, so it makes some sense to use what I've got. My
>>thinking is if it becomes annoying I can add the separate voltage
>>monitoring system after the fact. Tim at PP did mention that he
>>regularly sees OBAM guys using the EFIS for voltage monitoring, and
>>all too often they've got parameters set way too stringent, and get
>>many nuisance warnings. As yet I haven't investigated what parameters
>>and settings I can work with, so the external LV warning is always on
>>the table.
>>
>>
>>
>>Thanks very much for the thoughts Peter. It's very useful to think
>>through the questions and comments.
>>
>>
>>
>>Cheers
>>
>>Gerry
>>
>>
>>
>>
>>
>>------ Original Message ------
>>
>>From "Peter Pengilly" <peter@sportingaero.com>
>>
>>To aeroelectric-list@matronics.com
>>
>>Date 2023-12-29 2:11:12 AM
>>
>>Subject RE: AeroElectric-List: Tailwind Electrical System Drawing and
>>Power Analysis
>>
>>
>>
>>>Why do you want to switch the SD-8 alternator?
>>>
>>>Why switch battery power to the bus twice?
>>>
>>>Use an externally regulated main alternator to avoid having to switch
>>>the alternator output.
>>>
>>>Provide a method to connect the battery directly to the bus.
>>>
>>>Do not use a diode in the feed to the essential bus.
>>>
>>>There are a number of services connected directly to the battery just
>>>waiting to flatten it
>>>
>>>
>>>
>>>If the voltage of the SD8 is set (say) 0.2v lower than the main
>>>alternator it will not produce power if the main is on line. If the
>>>main fails it takes up the load.
>>>
>>>For my liking you have too many relays between the battery and the
>>>bus bar.
>>>
>>>If you use an externally regulated main alternator then initially
>>>only switch on the SD8 on start up. Then power up the main alternator
>>>regulator and bring that on line.
>>>
>>>Install a switch that powers up the essential (or main) bus directly
>>>from the battery, if the switch is a double pole use the second pole
>>>to disable the starter.
>>>
>>>The large diode in the feed line to the essential bus will always
>>>drop the voltage by an amount. The benefit is auto load shedding but
>>>do you need that with 2 alternators? If you really want to shed the
>>>main bus use a large switch and ensure there is a path to the
>>>essential bus directly from the battery. I used to have a feed diode
>>>and would not use one again.
>>>
>>>A diode is very beneficial on the starter contactor.
>>>
>>>Having a low voltage waring that is independent of the EFIS is
>>>useful. It is possible you will get immune to EFIS warnings
>>>
>>>
>>>
>>>Peter
>>>
>>>
>>>
>>>From:owner-aeroelectric-list-server@matronics.com
>>><owner-aeroelectric-list-server@matronics.com> On Behalf Of Gerry van
>>>Dyk
>>>Sent: Thursday, December 28, 2023 11:32 PM
>>>To:aeroelectric-list@matronics.com
>>>Subject: AeroElectric-List: Tailwind Electrical System Drawing and
>>>Power Analysis
>>>
>>>
>>>
>>>Hello again all
>>>
>>>Well, I think I'm ready for a good critique on my proposed electrical
>>>system for my Tailwind project. For the most part it's based on
>>>Z13/8, we're using a Plane Power AL12-E160 primary alternator, and of
>>>course the B&C SD-8 backup alternator. The E160 is internally
>>>regulated, and also has an internal crowbar system and alt-out panel
>>>light output, which I intend to use. The SD-8 has their older PMR1
>>>regulator, so we've got the external crowbar module and no voltage
>>>sensing. I've drawn these items as shown on their respective install
>>>instructions call for.
>>>
>>>
>>>
>>>As I mentioned earlier, I intended to start the engine on the
>>>endurance bus, and check the SD-8 operation during the startup
>>>procedure. I had neglected to think about where the starter was
>>>going to get power from, so the idea has forced an additional switch
>>>and relay (a rather robust one at that) to run the main bus. The
>>>battery contactor would be closed for startup, then the SD-8
>>>operation checked and finally the main bus would be brought up to
>>>begin normal operation.
>>>
>>>
>>>
>>>I'm a little uneasy about this extra switching, as I know this group
>>>is inclined toward fewer failure points, and with good reason. As I
>>>look at the 'textbook' Z13/8 drawing, with my dual EFIS, IFR capable
>>>panel in mind, it seems to me that a startup would bring the entire
>>>panel up with the main bus, then with the engine running I'd have to
>>>close the E-bus switch, open the battery contactor, dropping out half
>>>the instrument panel. Then check the backup alternator operation,
>>>and finally reboot the rest of the panel again. It just really feels
>>>rather clunky to me.
>>>
>>>
>>>
>>>Bob, have I missed something with the original architecture concept?
>>>Is there a way to check the backup alternator function while the main
>>>bus is up and running? It would certainly help me simplify my
>>>system.
>>>
>>>
>>>
>>>I'd appreciate if you good folks would give my drawing a good review.
>>> Questions, comments and critiques are all welcome.
>>>
>>>
>>>
>>>Thanks again
>>>
>>>Gerry van Dyk
>>>
>>>Tailwind C-GVDZ
>>>
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