Today's Message Index:
----------------------
1. 05:44 AM - Re: Endurance bus switch (John Keen)
2. 07:47 AM - Re: Endurance bus switch (user9253)
3. 09:31 AM - Circuit protection for backup alternator (Ed Godfrey)
4. 09:40 AM - Re: Circuit protection for backup alternator (Robert L. Nuckolls, III)
5. 09:42 AM - Re: Re: Endurance bus switch (Robert L. Nuckolls, III)
6. 12:12 PM - Voltmeter (H. Ivan Haecker)
7. 01:31 PM - Re: Circuit protection for backup alternator (Kelly McMullen)
8. 01:43 PM - Re: Re: Endurance bus switch (John Keen)
9. 02:04 PM - Re: Voltmeter (Robert L. Nuckolls, III)
10. 02:06 PM - Re: Circuit protection for backup alternator (Robert L. Nuckolls, III)
11. 02:10 PM - Interesting thread on overvoltage event (Charlie England)
12. 03:43 PM - Re: Circuit protection for backup alternator (Ed Godfrey)
13. 03:55 PM - Re: Circuit protection for backup alternator (Bill Watson)
14. 04:50 PM - Re: Interesting thread on overvoltage event (user9253)
15. 05:04 PM - Re: Re: Interesting thread on overvoltage event (Charlie England)
16. 05:20 PM - Re: Circuit protection for backup alternator (Kelly McMullen)
17. 05:29 PM - Re: Circuit protection for backup alternator (Robert L. Nuckolls, III)
18. 05:56 PM - Re: Re: Interesting thread on overvoltage event (Robert L. Nuckolls, III)
19. 06:35 PM - Re: Circuit protection for backup alternator (Ed Godfrey)
Message 1
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| Subject: | Re: Endurance bus switch |
Thanks Bob,
My design goal for battery only operations is to be able to focus on
flying the aeroplane easily to a safe landing at the nearest airfield.
As the plane has conventional dual mags and a carb with engine driven
fuel pump, and a traditional panel with vacuum AH and DG, I imagine
wanting electrical help mainly for navigating and communicating (day
VFR).
This is my list for the endurance bus, the numbers with a ? are current
draw that I=99ve guesstimated until I have the correct value:
- Panel floodlights x2 (in case day VFR runs out) = 0.15
- Van=99s Voltmeter = 1?
- Van=99s fuel gauges x2 = 1.5?
- Dual USB outlet (charges iPad = 0.85 and GPS = 0.5)
- Transponder Garmin 330ES = 4
- Comm radio (has built-in intercom) Garmin GTR200 = 7.5
- Boost pump = 0.8
Total = 16.3
Better - I had some very round and generous numbers previously giving me
the 24! And I=99ve taken off the hour meter.
This leaves out the alternator; starting system; nav, landing and
interior lights; engine instruments; turn coordinator, flaps and trim;
hour meter...
Cheers,
John.
> On 10 Apr 2017, at 01:05, Robert L. Nuckolls, III
<nuckolls.bob@aeroelectric.com> wrote:
>
> At 05:01 AM 4/9/2017, you wrote:
>> Hi Bob,
>>
>> I=C3=A2=C2=C2=99m building an RV-7 and tackling the wiring, thank
you for sharing the invaluable knowledge in your book.
>> I=C3=A2=C2=C2=99ve been grappling with whether or not to wire the
endurance bus directly through the switch or use a relay. The switch is
rated at 20 amps but the bus could conceivably see up to 24 amps if
everything on the bus was on and drawing its maximum, eg radio
transmitting, transponder transponding and GPS charging for example.
>
> The switch 'rating' is largely irrelevant. The
> number is an engineer's guide to service life
> under tens of thousands of cycles at full load.
>
> Your switch won't see 1000 cycles in its lifetime
> and never under full load.
>
> Tell us about this 'endurance' bus . . . what
> are your design goals for battery only operations
> and what electro-whizzies are fed from this bus?
>
>
>
> Bob . . .
>
Message 2
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| Subject: | Re: Endurance bus switch |
The current draw estimates are way too high.
The voltmeter and fuel gauges combined are probably less than one amp.
The Transponder is 3 amps.
The GTR 200 is probably less than 1 amp except when transmitting.
I guesstimate less than 8 amps total.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=468231#468231
Message 3
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| Subject: | Circuit protection for backup alternator |
Bob,
I am building an RV10 and installing a B&C 410H backup alternator. I
have installed an ANL circuit protection next to the battery behind the
baggage compartment, to protect the #6 wire that I have going forward,
along the lines of your Z-13/8 schematic. But I was concerned about the
output of the alternator going aft. I have a contactor on the firewall
for the output of the alternator and I was considering installing a
fusible link between the alternator and the contactor for protection.
Are there any issues that you might see with a setup like this? Thanks.
Ed Godfrey
Message 4
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| Subject: | Re: Circuit protection for backup alternator |
At 11:29 AM 4/10/2017, you wrote:
>
>Bob,
> I am building an RV10 and installing a B&C 410H backup
> alternator. I have installed an ANL circuit protection next to the
> battery behind the baggage compartment, to protect the #6 wire that
> I have going forward, along the lines of your Z-13/8 schematic. But
> I was concerned about the output of the alternator going aft. I
> have a contactor on the firewall for the output of the alternator
> and I was considering installing a fusible link between the
> alternator and the contactor for protection. Are there any issues
> that you might see with a setup like this? Thanks.
No . . . the alternator is incapable of delivering
current needed to put the b-lead at risk.
Bob . . .
Message 5
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| Subject: | Re: Endurance bus switch |
At 09:43 AM 4/10/2017, you wrote:
>
>The current draw estimates are way too high.
>The voltmeter and fuel gauges combined are probably less than one amp.
>The Transponder is 3 amps.
>The GTR 200 is probably less than 1 amp except when transmitting.
>I guesstimate less than 8 amps total.
Generally agree . . . transponder energy draw
is under 1A except for very short bursts while
replying . . . so I'll suggest your e-bus loads
are smaller yet probably 5A or less.
A simple toggle switch and 10A fuse protection
for your e-bus alternate feed will be entirely
adequate.
Bob . . .
Message 6
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Is there a best place to wire a voltmeter to my electrical system? Should I
be most interested in the voltage at the main bus? And if so, can I piggy
back the voltmeter to an existing breaker (such as other electric engine
gauges) or does the voltmeter need it's own separate protection. Hope my
question isn't too naive.
Ivan Haecker (rewiring my ancient rv-4)
Message 7
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| Subject: | Re: Circuit protection for backup alternator |
IMHO you are getting things backwards. You do not need protection for
the heavy wire from the battery to the firewall/starter solenoid.
However, that cable should be #4 minimum, and better #2.
Use the ANL to protect the B lead from the alternator to the main bus,
with the ammeter shunt either right above or below it on the firewall.
Your #6 (or #8) is appropriate for that B lead.
Kelly
RV-10 40866, flying
On 4/10/2017 9:29 AM, Ed Godfrey wrote:
> <egodfrey@ameritech.net>
>
> Bob,
> I am building an RV10 and installing a B&C 410H backup alternator. I
> have installed an ANL circuit protection next to the battery behind the
> baggage compartment, to protect the #6 wire that I have going forward,
> along the lines of your Z-13/8 schematic. But I was concerned about the
> output of the alternator going aft. I have a contactor on the firewall
> for the output of the alternator and I was considering installing a
> fusible link between the alternator and the contactor for protection.
> Are there any issues that you might see with a setup like this? Thanks.
>
> Ed Godfrey
>
>
Message 8
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| Subject: | Re: Endurance bus switch |
Thanks Joe, Bob!
Cheers,
John Keen
> On 11 Apr 2017, at 2:40 am, Robert L. Nuckolls, III <nuckolls.bob@aeroelec
tric.com> wrote:
>
> At 09:43 AM 4/10/2017, you wrote:
>>
>> The current draw estimates are way too high.
>> The voltmeter and fuel gauges combined are probably less than one amp.
>> The Transponder is 3 amps.
>> The GTR 200 is probably less than 1 amp except when transmitting.
>> I guesstimate less than 8 amps total.
>
> Generally agree . . . transponder energy draw
> is under 1A except for very short bursts while
> replying . . . so I'll suggest your e-bus loads
> are smaller yet probably 5A or less.
>
> A simple toggle switch and 10A fuse protection
> for your e-bus alternate feed will be entirely
> adequate.
>
> Bob . . .
Message 9
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At 02:05 PM 4/10/2017, you wrote:
>Is there a best place to wire a voltmeter to my electrical system?
>Should I be most interested in the voltage at the main bus?
generally, yes
> And if so, can I piggy back the voltmeter to an existing breaker
> (such as other electric engine gauges) or does the voltmeter need
> it's own separate protection. Hope my question isn't too naive.
Not at all. Tie it to any handy 5A breaker
on the main bus and wire it with 22AWG.
Alternatively you could simply drive the
voltmeter through its own 3A fuse in an
in-line fuseholder . . . easy to tuck behind
the panel.
Here's a guy who will sell you 5 holders with
small wire (18awg) more appropriate to this
task and 3A fuses to go with them for $10.
You'll have some holders/fuses left over but
you can't go down to Smiley Jack's Parts
Emporium and buy one holder and fuse after
you figure in time and mileage.
Bob . . .
Message 10
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| Subject: | Re: Circuit protection for backup alternator |
>>I have a contactor on the firewall for the output of the alternator
>>and I was considering installing a fusible link between the
>>alternator and the contactor for protection. Are there any issues
>>that you might see with a setup like this? Thanks.
You probably don't need that long #6 feeder . . .
you can feed the alternator's output into
the system at the starter contactor on the
firewall. A miniANL on a fuseblock or a
MAXI-blade in an in-line fuse holder could
be pressed into protection of this circuit
and eliminate the long wire run.
Bob . . .
Message 11
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| Subject: | Interesting thread on overvoltage event |
There's an ongoing thread over at the VAF (RV-x) forum about an
overvoltage event. Very few of those guys seem to be subscribed here,
and most are quite.... let's say, limited, in electrical knowledge.
This case involves an alternator overvoltage event with (apparently) an
internally regulated alternator in a plane with no automatic overvoltage
protection. Where it gets interesting is that he was running an EarthX
12V lithium iron battery. The suspicion is that the battery's protection
circuit protected the battery by disconnecting it, and even though most
of the avionics were capable of handling overvoltage events in a 28V
system, the sudden loss of the battery load allowed the alternator
voltage to go high enough to trash almost everything in the plane.
Talk about your load dump event.....
Just something to explore, for anyone considering a lithium chemistry
battery. Will manual shutdown of the alternator be fast enough? Will
even automated OV shutdown be fast enough?
Charlie
Message 12
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| Subject: | Re: Circuit protection for backup alternator |
Bob,
Following the Z-13/8, I am connecting up the backup alternator to
the hot side of the battery contactor. With the distance that the power
is traveling, I calculated that the #6 wire would be the best choice.
Did I choose wrong?
Ed
On 4/10/2017 4:04 PM, Robert L. Nuckolls, III wrote:
>>> I have a contactor on the firewall for the output of the alternator
>>> and I was considering installing a fusible link between the
>>> alternator and the contactor for protection. Are there any issues
>>> that you might see with a setup like this? Thanks.
>
> You probably don't need that long #6 feeder . . .
> you can feed the alternator's output into
> the system at the starter contactor on the
> firewall. A miniANL on a fuseblock or a
> MAXI-blade in an in-line fuse holder could
> be pressed into protection of this circuit
> and eliminate the long wire run.
>
> Bob . . .
>
Message 13
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| Subject: | Re: Circuit protection for backup alternator |
I have been flying my RV-10 with a 2 battery/2 alternator/2 bus Z-14
for 5+ years. Just for reference purposes my configuration includes:
* Both batteries and battery contactors are installed behind baggage
compartment
* 2 AWG wire used to to all contactors including a run forward of the
firewall for the starter contactor and the main alternator
* 8 AWG wire used for runs to 2 fuse blocks on cockpit sidewalls and
for run from SD20 alternator and it's battery contactor in the rear
* ANL current limiters installed on firewall close to alternators for
both B leads
* (there is no protection on runs from battery contactors in rear to
fuse blocks and starter in the front)
I wouldn't do it any differently if I did it again.
On 4/10/2017 12:29 PM, Ed Godfrey wrote:
> <egodfrey@ameritech.net>
>
> Bob,
> I am building an RV10 and installing a B&C 410H backup alternator.
> I have installed an ANL circuit protection next to the battery behind
> the baggage compartment, to protect the #6 wire that I have going
> forward, along the lines of your Z-13/8 schematic. But I was concerned
> about the output of the alternator going aft. I have a contactor on
> the firewall for the output of the alternator and I was considering
> installing a fusible link between the alternator and the contactor for
> protection. Are there any issues that you might see with a setup like
> this? Thanks.
>
> Ed Godfrey
>
>
---
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Message 14
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| Subject: | Re: Interesting thread on overvoltage event |
Here is a link to the VAF thread that Charlie mentioned.
http://www.vansairforce.com/community/showthread.php?p=1164359#post1164359
It seems that the pilot was unable to shut down the alternator with either the
field switch or master switch.
Anyone who installs a Lithium battery should read the Dynon Support post #7 in
that thread. Without aircraft electrical system over-voltage protection, a Lithium
battery could disconnect itself from the electrical system to protect itself
against an over-voltage event. Without a lead-acid battery to mitigate over-voltage,
very expensive avionics are at the mercy of a runaway alternator.
Post number 17 by Dynon Support is also interesting.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=468273#468273
Message 15
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| Subject: | Re: Interesting thread on overvoltage event |
Minor correction; the owner said he didn't turn off the master until
everything had died. He *might* have saved some stuff if he'd turned the
master off sooner.
On Mon, Apr 10, 2017 at 6:47 PM, user9253 <fransew@gmail.com> wrote:
>
> Here is a link to the VAF thread that Charlie mentioned.
> http://www.vansairforce.com/community/showthread.php?p=1164359#post1164359
> It seems that the pilot was unable to shut down the alternator with either
> the field switch or master switch.
> Anyone who installs a Lithium battery should read the Dynon Support post
> #7 in that thread. Without aircraft electrical system over-voltage
> protection, a Lithium battery could disconnect itself from the electrical
> system to protect itself against an over-voltage event. Without a
> lead-acid battery to mitigate over-voltage, very expensive avionics are at
> the mercy of a runaway alternator.
> Post number 17 by Dynon Support is also interesting.
>
> --------
> Joe Gores
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=468273#468273
>
>
Message 16
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| Subject: | Re: Circuit protection for backup alternator |
Normally, I would agree. However, the RV-10 requires the main battery
behind the baggage compartment for W&B, so it does require one long
heavy lead from the battery to the firewall. IMHO it should be no less
than #4, and really should be #2 for good starter performance, given the
over 10 ft run from battery to starter. Ground is handled through the
aluminum airframe for the battery. Very conventional with master relay
at the battery and starter relay on firewall near where the battery
heavy lead comes through. Vans publishes a basic wiring diagram that is
very conventional for a VFR aircraft, that gives a good starting point
for wire sizes and physical locations. It is easy to modify to meet
goals for endurance bus, redundancy, etc.
On 4/10/2017 2:04 PM, Robert L. Nuckolls, III wrote:
>>> I have a contactor on the firewall for the output of the alternator
>>> and I was considering installing a fusible link between the
>>> alternator and the contactor for protection. Are there any issues
>>> that you might see with a setup like this? Thanks.
>
> You probably don't need that long #6 feeder . . .
> you can feed the alternator's output into
> the system at the starter contactor on the
> firewall. A miniANL on a fuseblock or a
> MAXI-blade in an in-line fuse holder could
> be pressed into protection of this circuit
> and eliminate the long wire run.
>
> Bob . . .
>
Message 17
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| Subject: | Re: Circuit protection for backup alternator |
At 05:39 PM 4/10/2017, you wrote:
>Bob,
> Following the Z-13/8, I am connecting up the backup alternator
> to the hot side of the battery contactor. With the distance that
> the power is traveling, I calculated that the #6 wire would be the
> best choice. Did I choose wrong?
How about Z12 instead? Tie both alternators to
the bus structure at the hot side of the starter
contactor.
Just use the smaller alternator like a stand-by
device like hundreds of TC aircraft. Which
regulator are you using on the small alternator?
Z-13/8 was crafted specifically for minimizing loads
on the diminutive SD-8 alternator with bypassing
the battery contactor. The extra snort
available from the larger wound field makes this
a moot point . . . Z12 would simplify your wiring.
Bob . . .
Message 18
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| Subject: | Re: Interesting thread on overvoltage event |
At 06:47 PM 4/10/2017, you wrote:
>
>Here is a link to the VAF thread that Charlie mentioned.
>http://www.vansairforce.com/community/showthread.php?p=1164359#post1164359
>It seems that the pilot was unable to shut down the alternator with
>either the field switch or master switch.
>Anyone who installs a Lithium battery should read the Dynon Support
>post #7 in that thread. Without aircraft electrical system
>over-voltage protection, a Lithium battery could disconnect itself
>from the electrical system to protect itself against an over-voltage
>event. Without a lead-acid battery to mitigate over-voltage, very
>expensive avionics are at the mercy of a runaway alternator.
>Post number 17 by Dynon Support is also interesting.
The assertions made in this posting are largely
correct. The stock internally regulated alternator
has failure modes for ov conditions that cannot
be controlled from the outside.
With no battery on line to grunt the excess energy,
bus voltages of 100-200 volts are easily realized.
I had conversation with folks about this
very topic last week . . . the event chronicled
on the RV forum may have triggered the queries.
The battery has always been a CRITICAL component
of the overvoltage mitigation dynamic. The
auto-disconnect feature in EarthX batteries is
understandable from the battery safety
perspective . . . but it may upset the apple cart
when it fails to perform legacy duties expected
of lead-acid batteries.
Bob . . .
Message 19
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| Subject: | Re: Circuit protection for backup alternator |
Bob,
I am using the SB1B-14 regulator.
Ed
On 4/10/2017 7:26 PM, Robert L. Nuckolls, III wrote:
> At 05:39 PM 4/10/2017, you wrote:
>> Bob,
>> Following the Z-13/8, I am connecting up the backup alternator to
>> the hot side of the battery contactor. With the distance that the
>> power is traveling, I calculated that the #6 wire would be the best
>> choice. Did I choose wrong?
>
> How about Z12 instead? Tie both alternators to
> the bus structure at the hot side of the starter
> contactor.
>
> Just use the smaller alternator like a stand-by
> device like hundreds of TC aircraft. Which
> regulator are you using on the small alternator?
>
> Z-13/8 was crafted specifically for minimizing loads
> on the diminutive SD-8 alternator with bypassing
> the battery contactor. The extra snort
> available from the larger wound field makes this
> a moot point . . . Z12 would simplify your wiring.
>
>
> Bob . . .
>
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