Today's Message Index:
----------------------
1. 12:31 AM - Re: Car clock in an aircraft (John Tipton)
2. 04:38 AM - Re: Please critique my electrical design (N884RA)
3. 05:42 AM - Re: Please critique my electrical design (Charlie England)
4. 07:27 AM - Re: Car clock in an aircraft ()
5. 09:00 AM - Re: Please critique my electrical design (Ken Ryan)
6. 11:04 AM - Re: Please critique my electrical design (Robert L. Nuckolls, III)
7. 12:04 PM - Re: Car clock in an aircraft (Robert L. Nuckolls, III)
8. 12:09 PM - Re: Re: Please critique my electrical design (Robert L. Nuckolls, III)
9. 12:13 PM - Re: Please critique my electrical design (Ken Ryan)
10. 12:47 PM - Re: Please critique my electrical design (Robert L. Nuckolls, III)
11. 12:56 PM - Re: Please critique my electrical design (Robert L. Nuckolls, III)
12. 01:13 PM - Re: Car clock in an aircraft (Eric Page)
13. 01:30 PM - Re: Please critique my electrical design (Mark Moyle)
14. 01:43 PM - Re: Please critique my electrical design (N884RA)
15. 08:55 PM - Re: Please critique my electrical design (Robert L. Nuckolls, III)
16. 11:15 PM - Re: Please critique my electrical design (Jan de Jong)
Message 1
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| Subject: | Re: Car clock in an aircraft |
Hi Carlos
Do you have an 'off aircraft' battery/power sauce to run a test on this clock,
as for aircraft power, any low current item (instrument lights) could share its
power supply and fuse/CB I would imagine
Regards
John
Sent from my iPad
----x--O--x----
> On 10 Apr 2018, at 10:40 pm, Carlos Trigo <trigo@mail.telepac.pt> wrote:
>
>
> To the electrowizzards in this list.
> (This is not a rocket science aircraft subject, but I need your help on this)
>
> I bought one of those cheap (chinese) digital car clocks, with temperature indication,
to install in the back of my RV-10, as a courtesy to the rear passengers.
(please avoid any comments on this decision... :-)).
> As one could expect, the miserable instructions leaflet which came with the clock,
doesnt have any information about the electric circuit, so Im in the guess
field here.
>
> This critter has a 2-wire cable to be connected to 12V/24V, and also has 2 of
those coin type batteries, so I suppose that the batteries are a backup to the
ships power.
> But Im not sure...
>
> This leaves me with a doubt on where to connect the + wire of the power cable.
> Should I connect it to a circuit which is only powered when the aircraft Master
switch is on, to avoid this critter to deplete the aircraft battery?
> Or can I connect it to the always hot bus, hoping that when the Master is Off,
the clocks coin batteries will be powering the clock and only a very tiny current
will be draining from the always hot bus, not depleting the aircrafts battery?
>
> Even knowing that without information on the clocks electric circuit it is difficult
to know the answer, comments and suggestions are welcome
>
> Thanks
> Carlos
>
>
>
>
Message 2
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| Subject: | Re: Please critique my electrical design |
user9253 wrote:
> If you look at B&C's wiring diagram
> https://www.bandc.aero/pdfs/LR3C_Installation_Manual.pdf
> the voltage sense terminal 3 is separate from the field terminal 6.
> Also look at Bob's Z-12.
I followed B&C's parts list, but when they switched it from a generic Ford regulator
to the LR3C I didn't realize I should have used the Z-12 architecture for
that component. Z-12 doesn't include a fuseable link or crowbar -- should I
take those out? I put the LV Warn light back in my design for now like the Z-12
has, but I'm sure the G3X has an input for that, so a stand-alone light won't
be required. I'll also have to figure out if I still need the Lo Volt Warn
CB in that arrangement.
> One fuselink provides protection for everything downstream of it.
> A second fuselink is not required. All the second one does is make
> an unnecessary failure point.
That makes sense now, thanks!
> The maximum of 6" rule of thumb for unprotected wires is not cast
> in stone. It all depends on what dangers the wire is exposed to.
I updated my design this morning, and removed the second fuseable link.
> Circuit breakers are mechanical devices that take time to operate.
> That time could be longer than it takes a smaller fuse to blow. A larger
> fuse will be slower to blow in case of the over-voltage module shorting out.
> The aux alternator fuse protects the battery. It will not hurt to use a 30
> amp fuse. Z-13/8 uses a 20awg fuselink which will probably carry more
> than 30 amps before the wire melts. The aux alternator output is self
> current limiting and will never exceed 10 amps or so.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=479262#479262
Message 3
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| Subject: | Re: Please critique my electrical design |
Well, the 1st issue is establishing what Mark meant when he mentioned that
10.6V limit. Because unless he's using a truly massively oversized battery,
it will *always* drop below 10.6V during cranking. That's why old Kettering
ignition (points & condenser) cars had ballast resistors in series with
their points. The points actually run on around 6-8 volts, and resistor
gets switched out of the circuit during cranking because of the battery
voltage drop due to cranking loads. Dropping down around 10V (sometimes
even lower) is fairly common during starting. Look back through the
archives for all the complaints about EFISs rebooting while cranking the
engine.
So....I'm betting that Mark meant he's measuring 10.6V *after* 15 seconds
of cranking, but with no/minimal load on the battery. Now, go back to the
Corvette/Chevette example. If you accelerate the Corvette for 15 seconds,
it'll still have 400 HP, but you may only have 3 seconds of capacity (gas)
left.
Mark's test is even less valid if one has chosen a Lithium chemistry
battery; their voltage has much less decline until it 'falls off the cliff'
at full discharge.
The real test is monitoring *how long* voltage remains above the voltage
that indicates complete discharge (which is around 10.5 V), while the
typical load from the plane's required (endurance bus) electronics is
applied.
On Tue, Apr 10, 2018 at 11:24 PM, Ken Ryan <keninalaska@gmail.com> wrote:
> Charlie, It seems to me that your response does not address that the test
> involves monitoring the voltage drop that occurs when the consistent load
> is applied. The test is not simply, "will the battery spin the prop." The
> test is, "what is the voltage drop caused by spinning the prop."
>
> It seems to me that if the voltage drops down further on a worn out
> battery than it does on a fresh battery, there is at least the possibilit
y
> that this test could be quite useful. It does not seem to me that the
> simple fact the battery "can be down 50% capacity and still reliably cran
k
> the engine" is germane to whether or not monitoring voltage under a
> consistent load (in this case spinning the propeller for a specific time)
> can be useful as a way to determine whether or not it is time to replace
a
> battery.
>
> I'm not saying that the spin-the-prop-and-monitor-voltage test is valid.
> But it seems to me like it might be. I just can't see where simply notin
g
> that a depleted battery can still spin a prop says anything about the
> usefulness of such a test. Sorry, but I just can't seem to make that
> connection. Probably I am a little bit dense :) -- it wouldn't be the fir
st
> time.
>
> In evaluating the suggested test, as a starting point I would like to kno
w
> if the voltage drop would be significantly different on a new vs a worn o
ut
> battery. If the answer is no, the drop would be about the same, then case
> closed. Test invalid. But if it turns out the voltage drop is significant
ly
> greater on a worn out battery, then I think there is reason to believe th
at
> the test might be useful.
>
>
> On Tue, Apr 10, 2018, 20:04 Charlie England <ceengland7@gmail.com> wrote:
>
>> If the only use for the battery is starting, then it's a valid test. But
>> if the battery is backup electrical power for the alternator and you nee
d
>> electrical power to keep the flight safe to its conclusion, then it isn'
t a
>> valid test.
>>
>> It can be down to 50% capacity & still reliably crank the engine. But if
>> the alternator dies and you need the battery to keep the engine running
>> (electronic ignition, glass panel in IFR, etc), then you'd only have hal
f
>> or less the time you thought you'd have, based on the battery's rated
>> capacity.
>>
>> It's the difference between power and energy. 400 HP Corvette with 1/2
>> gallon of gas, vs 80 HP Chevette with 15 gallons.
>>
>> That help?
>>
>> On 4/10/2018 10:06 PM, Ken Ryan wrote:
>>
>> Charlie, It would seem to me that putting a consistent load (turning the
>> starter, similar temperatures) on the battery, and noting the voltage dr
op
>> would constitute a valid test. It is surely not the most accurate, but i
f
>> done in a consistent manner, it is seems it would be much better than do
ing
>> nothing at all. Also, I don't see how the fact that it only takes 5% of
>> battery capacity to start the engine has any relevance on whether such a
>> rudimentary engine spinning stress test is valid, or not. Are you saying
>> that it is likely that one would note the same voltage drop on a brand n
ew
>> battery as on a battery that is nearing the end of its useful life?
>> Enlighten!
>>
>> On Tue, Apr 10, 2018 at 6:39 PM, Charlie England <ceengland7@gmail.com>
>> wrote:
>>
>>> Since it only takes around 5% of capacity to start the engine, that
>>> might not be the most reliable test.
>>>
>>> On 4/10/2018 7:06 PM, Mark Moyle wrote:
>>>
>>> Quick load test on a battery ismags grounded or off and mixtur
e
>>> pulled. Crank the engine and monitor the battery voltage. If after 15
>>> seconds the battery voltage does NOT drop below 10.6 volts DC the batte
ry
>>> is good. If not charge the battery and test again.
>>> Mark Moyle
>>> Platinum Alaska
>>>
>>> From: <owner-aeroelectric-list-server@matronics.com> on behalf of Rene
<
>>> rene@felker.com>
>>> Date: Tuesday, April 10, 2018 at 3:35 PM
>>> To: <aeroelectric-list@matronics.com>
>>> Subject: RE: AeroElectric-List: Please critique my electrical design
>>>
>>> I do not know about what sells..but I have mine load tested at
>>> Batteries +.
>>>
>>>
>>>
>>> I have two batteries and two alternators. I have one battery that is
>>> 10+ years and the other is about 5 now. I had two battery failures
.one
>>> self induced and the other was infant mortality.
>>>
>>>
>>>
>>> Rene'
>>>
>>> 801-721-6080
>>>
>>>
>>>
>>> *From:* owner-aeroelectric-list-server@matronics.com <
>>> owner-aeroelectric-list-server@matronics.com> *On Behalf Of *FLYaDIVE
>>> *Sent:* Tuesday, April 10, 2018 5:15 PM
>>> *To:* aeroelectric-list@matronics.com
>>> *Subject:* Re: AeroElectric-List: Please critique my electrical design
>>>
>>>
>>>
>>> Bob:
>>>
>>>
>>>
>>> Let's get a show of hands...
>>>
>>> How many Pilots out there have a LOAD tester?
>>>
>>> I can't get owners to check their tires and you want them to load test
a
>>> battery!
>>>
>>> Granted! This is a aero-electric email list and many are builders. So
,
>>> if there are fellows out there that do have a load tester I doubt that
>>> would cover the rest of the BUYERS that only purchased the plane and di
d
>>> not build.
>>>
>>> What do you think would sell a plane faster:
>>>
>>> 'Oh, and this plane has Dual Alternators and Dual Batteries.'
>>>
>>> Or...
>>>
>>> 'And every year at annual I Load Test the battery."
>>>
>>>
>>>
>>> Barry
>>>
>>>
>>>
>>>
>>>
>>> On Tue, Apr 10, 2018 at 4:44 PM, Robert L. Nuckolls, III <
>>> nuckolls.bob@aeroelectric.com> wrote:
>>>
>>> At 03:01 PM 4/10/2018, you wrote:
>>>
>>>
>>> =C3=82 With two alternators, why a backup battery?
>>>
>>> =C3=82 Bob . . .
>>>
>>>
>>> =C3=A2=82=AC=B9Because what if the battery fails?
>>> G-5's can have the Garmin $150 TINNY battery or =C3=A2=82=AC
=B9you can apply that
>>> money to a much larger second battery which will be big enough to start
the
>>> plane and supply days of power for the G-5.=C3=82 I have not installed
the
>>> G-3,=C3=82 but I have installed 2 planes with Dual G-5's (AI & HSI).
=C3=82 With
>>> dual G-5's in a certified plane you are required to=C3=82
>>> have dual Garmin batteries...=C3=82 That is $300 for a stinking 1 or 2
AH
>>> battery.=C3=82 Yea, I would be very happy to install a second battery
- a small
>>> one - With just enough to start the plane in a 24:00 DARK stranded
>>> situation.=C3=82 =C3=82
>>> Yea, happened to me one night.=C3=82 No Fun!
>>>
>>> Barry
>>>
>>>
>>> Was this in spite of a considered preventative
>>> maintenance program? What was the battery's last
>>> cap-check value before the failure?
>>>
>>> A battery that is watched and maintained as
>>> carefully as tires, belts, propeller nicks
>>> air cleaners and engine oil is very unlikely
>>> to fail. Dual alternators virtually assures
>>> you of engine driven energy in spite of the
>>> loss of one alternator.
>>>
>>> The rule of thumb for battery replacement
>>> in the TC world is when it falls to less than
>>> 75% of original capacity . . . in the modern
>>> RG battery world, this means it probably
>>> still cranks the engine but is in substantial
>>> decline on an ever increasing slope to failure
>>> yet unlikely to go belly up away from your
>>> home hangar.
>>>
>>> Few light aircraft owner's manuals speak to
>>> affirmative-action maintenance programs . . .
>>> but I'd bet that top-billing in the cast of performers
>>> virtually all dark-n-stormy night stories that
>>> speak to battery failure is a beyond-service-life
>>> battery.
>>>
>>>
>>> Bob . . .
>>>
>>>
>>>
>>>
>>>
>>>
>>> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&u
tm_campaign=sig-email&utm_content=emailclient&utm_term=icon> Virus-fr
ee.
>>> www.avast.com
>>> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&u
tm_campaign=sig-email&utm_content=emailclient&utm_term=link>
>>> <#m_-6378004472635657997_m_-615151073569806401_m_-960492680129280463_m_
6581499881476749600_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>>>
>>
>>
>>
Message 4
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| Subject: | Car clock in an aircraft |
Hm. If it works without being wired in, why not just leave it powered
by the button cell batteries? Seems like a "non-essential" item to me,
and I would hate for there to be ANY possibility it might drain the
battery over time.
Jim Parker
-------- Original Message --------
Subject: AeroElectric-List: Car clock in an aircraft
From: Carlos Trigo <trigo@mail.telepac.pt>
<trigo@mail.telepac.pt>
To the electrowizzards in this list.
(This is not a rocket science aircraft subject, but I need your help on
this)
I bought one of those cheap (chinese) digital car clocks, with
temperature indication, to install in the back of my RV-10, as a
courtesy to the rear passengers. (please avoid any comments on this
decision... :-)).
As one could expect, the miserable instructions leaflet which came with
the clock, doesnt have any information about the electric circuit, so
Im in the guess field here.
This critter has a 2-wire cable to be connected to 12V/24V, and also has
2 of those coin type batteries, so I suppose that the batteries are a
backup to the ships power.
But Im not sure...
This leaves me with a doubt on where to connect the + wire of the power
cable.
Should I connect it to a circuit which is only powered when the aircraft
Master switch is on, to avoid this critter to deplete the aircraft
battery?
Or can I connect it to the always hot bus, hoping that when the Master
is Off, the clocks coin batteries will be powering the clock and only
a very tiny current will be draining from the always hot bus, not
depleting the aircrafts battery?
Even knowing that without information on the clocks electric circuit
it is difficult to know the answer, comments and suggestions are welcome
Thanks
Carlos
Message 5
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| Subject: | Re: Please critique my electrical design |
Thanks Charlie.
On Wed, Apr 11, 2018 at 4:41 AM, Charlie England <ceengland7@gmail.com>
wrote:
> Well, the 1st issue is establishing what Mark meant when he mentioned tha
t
> 10.6V limit. Because unless he's using a truly massively oversized batter
y,
> it will *always* drop below 10.6V during cranking. That's why old Ketteri
ng
> ignition (points & condenser) cars had ballast resistors in series with
> their points. The points actually run on around 6-8 volts, and resistor
> gets switched out of the circuit during cranking because of the battery
> voltage drop due to cranking loads. Dropping down around 10V (sometimes
> even lower) is fairly common during starting. Look back through the
> archives for all the complaints about EFISs rebooting while cranking the
> engine.
>
> So....I'm betting that Mark meant he's measuring 10.6V *after* 15 seconds
> of cranking, but with no/minimal load on the battery. Now, go back to the
> Corvette/Chevette example. If you accelerate the Corvette for 15 seconds,
> it'll still have 400 HP, but you may only have 3 seconds of capacity (gas
)
> left.
>
> Mark's test is even less valid if one has chosen a Lithium chemistry
> battery; their voltage has much less decline until it 'falls off the clif
f'
> at full discharge.
>
> The real test is monitoring *how long* voltage remains above the voltage
> that indicates complete discharge (which is around 10.5 V), while the
> typical load from the plane's required (endurance bus) electronics is
> applied.
>
>
> On Tue, Apr 10, 2018 at 11:24 PM, Ken Ryan <keninalaska@gmail.com> wrote:
>
>> Charlie, It seems to me that your response does not address that the tes
t
>> involves monitoring the voltage drop that occurs when the consistent loa
d
>> is applied. The test is not simply, "will the battery spin the prop." Th
e
>> test is, "what is the voltage drop caused by spinning the prop."
>>
>> It seems to me that if the voltage drops down further on a worn out
>> battery than it does on a fresh battery, there is at least the possibili
ty
>> that this test could be quite useful. It does not seem to me that the
>> simple fact the battery "can be down 50% capacity and still reliably cra
nk
>> the engine" is germane to whether or not monitoring voltage under a
>> consistent load (in this case spinning the propeller for a specific time
)
>> can be useful as a way to determine whether or not it is time to replace
a
>> battery.
>>
>> I'm not saying that the spin-the-prop-and-monitor-voltage test is valid.
>> But it seems to me like it might be. I just can't see where simply noti
ng
>> that a depleted battery can still spin a prop says anything about the
>> usefulness of such a test. Sorry, but I just can't seem to make that
>> connection. Probably I am a little bit dense :) -- it wouldn't be the fi
rst
>> time.
>>
>> In evaluating the suggested test, as a starting point I would like to
>> know if the voltage drop would be significantly different on a new vs a
>> worn out battery. If the answer is no, the drop would be about the same,
>> then case closed. Test invalid. But if it turns out the voltage drop is
>> significantly greater on a worn out battery, then I think there is reaso
n
>> to believe that the test might be useful.
>>
>>
>>
>>
>> On Tue, Apr 10, 2018, 20:04 Charlie England <ceengland7@gmail.com> wrote
:
>>
>>> If the only use for the battery is starting, then it's a valid test. Bu
t
>>> if the battery is backup electrical power for the alternator and you ne
ed
>>> electrical power to keep the flight safe to its conclusion, then it isn
't a
>>> valid test.
>>>
>>> It can be down to 50% capacity & still reliably crank the engine. But i
f
>>> the alternator dies and you need the battery to keep the engine running
>>> (electronic ignition, glass panel in IFR, etc), then you'd only have ha
lf
>>> or less the time you thought you'd have, based on the battery's rated
>>> capacity.
>>>
>>> It's the difference between power and energy. 400 HP Corvette with 1/2
>>> gallon of gas, vs 80 HP Chevette with 15 gallons.
>>>
>>> That help?
>>>
>>> On 4/10/2018 10:06 PM, Ken Ryan wrote:
>>>
>>> Charlie, It would seem to me that putting a consistent load (turning th
e
>>> starter, similar temperatures) on the battery, and noting the voltage d
rop
>>> would constitute a valid test. It is surely not the most accurate, but
if
>>> done in a consistent manner, it is seems it would be much better than d
oing
>>> nothing at all. Also, I don't see how the fact that it only takes 5% of
>>> battery capacity to start the engine has any relevance on whether such
a
>>> rudimentary engine spinning stress test is valid, or not. Are you sayin
g
>>> that it is likely that one would note the same voltage drop on a brand
new
>>> battery as on a battery that is nearing the end of its useful life?
>>> Enlighten!
>>>
>>> On Tue, Apr 10, 2018 at 6:39 PM, Charlie England <ceengland7@gmail.com>
>>> wrote:
>>>
>>>> Since it only takes around 5% of capacity to start the engine, that
>>>> might not be the most reliable test.
>>>>
>>>> On 4/10/2018 7:06 PM, Mark Moyle wrote:
>>>>
>>>> Quick load test on a battery ismags grounded or off and mixtu
re
>>>> pulled. Crank the engine and monitor the battery voltage. If after 1
5
>>>> seconds the battery voltage does NOT drop below 10.6 volts DC the batt
ery
>>>> is good. If not charge the battery and test again.
>>>> Mark Moyle
>>>> Platinum Alaska
>>>>
>>>> From: <owner-aeroelectric-list-server@matronics.com> on behalf of Rene
>>>> <rene@felker.com>
>>>> Date: Tuesday, April 10, 2018 at 3:35 PM
>>>> To: <aeroelectric-list@matronics.com>
>>>> Subject: RE: AeroElectric-List: Please critique my electrical design
>>>>
>>>> I do not know about what sells..but I have mine load tested a
t
>>>> Batteries +.
>>>>
>>>>
>>>>
>>>> I have two batteries and two alternators. I have one battery that is
>>>> 10+ years and the other is about 5 now. I had two battery failures
.one
>>>> self induced and the other was infant mortality.
>>>>
>>>>
>>>>
>>>> Rene'
>>>>
>>>> 801-721-6080
>>>>
>>>>
>>>>
>>>> *From:* owner-aeroelectric-list-server@matronics.com <
>>>> owner-aeroelectric-list-server@matronics.com> *On Behalf Of *FLYaDIVE
>>>> *Sent:* Tuesday, April 10, 2018 5:15 PM
>>>> *To:* aeroelectric-list@matronics.com
>>>> *Subject:* Re: AeroElectric-List: Please critique my electrical design
>>>>
>>>>
>>>>
>>>> Bob:
>>>>
>>>>
>>>>
>>>> Let's get a show of hands...
>>>>
>>>> How many Pilots out there have a LOAD tester?
>>>>
>>>> I can't get owners to check their tires and you want them to load test
>>>> a battery!
>>>>
>>>> Granted! This is a aero-electric email list and many are builders.
>>>> So, if there are fellows out there that do have a load tester I doubt
that
>>>> would cover the rest of the BUYERS that only purchased the plane and d
id
>>>> not build.
>>>>
>>>> What do you think would sell a plane faster:
>>>>
>>>> 'Oh, and this plane has Dual Alternators and Dual Batteries.'
>>>>
>>>> Or...
>>>>
>>>> 'And every year at annual I Load Test the battery."
>>>>
>>>>
>>>>
>>>> Barry
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Tue, Apr 10, 2018 at 4:44 PM, Robert L. Nuckolls, III <
>>>> nuckolls.bob@aeroelectric.com> wrote:
>>>>
>>>> At 03:01 PM 4/10/2018, you wrote:
>>>>
>>>>
>>>> =C3=82 With two alternators, why a backup battery?
>>>>
>>>> =C3=82 Bob . . .
>>>>
>>>>
>>>> =C3=A2=82=AC=B9Because what if the battery fails?
>>>> G-5's can have the Garmin $150 TINNY battery or =C3=A2=82=AC
=B9you can apply that
>>>> money to a much larger second battery which will be big enough to star
t the
>>>> plane and supply days of power for the G-5.=C3=82 I have not installe
d the
>>>> G-3,=C3=82 but I have installed 2 planes with Dual G-5's (AI & HSI).
=C3=82 With
>>>> dual G-5's in a certified plane you are required to=C3=82
>>>> have dual Garmin batteries...=C3=82 That is $300 for a stinking 1 or
2 AH
>>>> battery.=C3=82 Yea, I would be very happy to install a second battery
- a small
>>>> one - With just enough to start the plane in a 24:00 DARK stranded
>>>> situation.=C3=82 =C3=82
>>>> Yea, happened to me one night.=C3=82 No Fun!
>>>>
>>>> Barry
>>>>
>>>>
>>>> Was this in spite of a considered preventative
>>>> maintenance program? What was the battery's last
>>>> cap-check value before the failure?
>>>>
>>>> A battery that is watched and maintained as
>>>> carefully as tires, belts, propeller nicks
>>>> air cleaners and engine oil is very unlikely
>>>> to fail. Dual alternators virtually assures
>>>> you of engine driven energy in spite of the
>>>> loss of one alternator.
>>>>
>>>> The rule of thumb for battery replacement
>>>> in the TC world is when it falls to less than
>>>> 75% of original capacity . . . in the modern
>>>> RG battery world, this means it probably
>>>> still cranks the engine but is in substantial
>>>> decline on an ever increasing slope to failure
>>>> yet unlikely to go belly up away from your
>>>> home hangar.
>>>>
>>>> Few light aircraft owner's manuals speak to
>>>> affirmative-action maintenance programs . . .
>>>> but I'd bet that top-billing in the cast of performers
>>>> virtually all dark-n-stormy night stories that
>>>> speak to battery failure is a beyond-service-life
>>>> battery.
>>>>
>>>>
>>>> Bob . . .
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&
utm_campaign=sig-email&utm_content=emailclient&utm_term=icon> Virus-f
ree.
>>>> www.avast.com
>>>> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&
utm_campaign=sig-email&utm_content=emailclient&utm_term=link>
>>>> <#m_-3808612535981414965_m_-6378004472635657997_m_-615151073569806401_
m_-960492680129280463_m_6581499881476749600_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F
9FDF2>
>>>>
>>>
>>>
>>>
>
Message 6
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| Subject: | Re: Please critique my electrical design |
At 06:14 PM 4/10/2018, you wrote:
>Bob:
>
>Let's get a show of hands...
>How many Pilots out there have a LOAD tester?
not load . . . capacity
>I can't get owners to check their tires and you
>want them to load test a battery!
That's a separate issue. Lots of folks
fail to take their drugs as prescribed.
>Granted!=C2 This is a aero-electric email list
>and many are builders.=C2 So, if there are
>fellows out there that do have a load tester I
>doubt that would cover the rest of the BUYERS
>that only purchased the plane and did not build.
I don't design systems for marketability.
I strive for failure tolerance and
risk reduction.
>What do you think would sell a plane faster:
>'Oh, and this plane has Dual Alternators and Dual Batteries.'
>Or...
>'And every year at annual I Load Test the battery."
If you've got an e-bus, then a cap test
is easy. While doing other things on the
airplane, set the cockpit up for endurance
mode and see if the battery will run your
electro-whizzies for at least 75 percent
of time as when the battery was new.
Failure to honor critical axioms in aviation
present increased risks . . . you have to
make sure that fuel aboard is MORE than
sufficient to the mission. Some builders
with e-bus structures will size the battery
and endurance mode operations such that
electrical capacity exceeds fuel capacity.
The point being offered is that an electrical
system can be configured and used in a manner
that makes an electrical emergency exceedingly
unlikely. I try to remind people that when
'standby' equipment is being installed, it comes
with cost, weight and maintenance issues.
Therefore, is it not useful to consider ways that
standby equipment becomes smaller, lighter, less
expensive and/or more efficient . . . if not
eliminated all together? If one is unwilling to
put a dip-stick into the energy contained in the
ship's main battery . . . how is a standby battery
going to be treated any differently?
Bob . . .
Message 7
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| Subject: | Car clock in an aircraft |
At 09:26 AM 4/11/2018, you wrote:
>
>Hm. If it works without being wired in, why not just leave it powered
>by the button cell batteries? Seems like a "non-essential" item to me,
>and I would hate for there to be ANY possibility it might drain the
>battery over time.
If any accessory powered internally by a 'button cell'
is fitted with an external power connection, I would
wonder if external power isn't just for lighting.
Button cell capacities are very low . . . digital
devices that use them will have current drains
measured in microamps. If the external power does
indeed supplement the internal battery, then drain
on that lead will be insignificant with respect to
energy stored in the ship's battery. Similarly,
electric clocks in car's used to be powered directly
from the battery with no significant impact on
the system's availability.
If the external lead is to power panel illumination,
then consumption will be much higher . . . but
probably independent of electronics. Hence needs
voltage only while the airplane is powered up.
Bob . . .
Message 8
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| Subject: | Re: Please critique my electrical design |
>
>I followed B&C's parts list, but when they switched it from a
>generic Ford regulator to the LR3C I didn't realize I should have
>used the Z-12 architecture for that component. Z-12 doesn't include
>a fuseable link or crowbar -- should I take those out?
The ovm14 can come out, that's built into the LR3.
If your using a fused bus, then the fusible link
and remotely located field breaker stays in.
> I put the LV Warn light back in my design for now like the Z-12
> has, but I'm sure the G3X has an input for that, so a stand-alone
> light won't be required.
the G3x has its own low voltage sense, resolution
and display feature. If you don't wish to use the
separate light featured in the LR3C installation,
just leave that terminal unused.
> I'll also have to figure out if I still need the Lo Volt Warn CB
> in that arrangement.
YES! that is your bus voltage sense lead.
Bob . . .
Message 9
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| Subject: | Re: Please critique my electrical design |
Bob, thanks for reiterating the difference between a load test and a
capacity test. Is there any possibility of gaining insight into a battery's
capacity by studying the results of load testing?
On Wed, Apr 11, 2018 at 10:03 AM, Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> At 06:14 PM 4/10/2018, you wrote:
>
> Bob:
>
> Let's get a show of hands...
> How many Pilots out there have a LOAD tester?
>
>
> not load . . . capacity
>
> I can't get owners to check their tires and you want them to load test a
> battery!
>
>
> That's a separate issue. Lots of folks
> fail to take their drugs as prescribed.
>
> Granted!=C3=82 This is a aero-electric email list and many are builders.
=C3=82 So,
> if there are fellows out there that do have a load tester I doubt that
> would cover the rest of the BUYERS that only purchased the plane and did
> not build.
>
>
> I don't design systems for marketability.
> I strive for failure tolerance and
> risk reduction.
>
> What do you think would sell a plane faster:
> 'Oh, and this plane has Dual Alternators and Dual Batteries.'
> Or...
> 'And every year at annual I Load Test the battery."
>
>
> If you've got an e-bus, then a cap test
> is easy. While doing other things on the
> airplane, set the cockpit up for endurance
> mode and see if the battery will run your
> electro-whizzies for at least 75 percent
> of time as when the battery was new.
>
> Failure to honor critical axioms in aviation
> present increased risks . . . you have to
> make sure that fuel aboard is MORE than
> sufficient to the mission. Some builders
> with e-bus structures will size the battery
> and endurance mode operations such that
> electrical capacity exceeds fuel capacity.
>
> The point being offered is that an electrical
> system can be configured and used in a manner
> that makes an electrical emergency exceedingly
> unlikely. I try to remind people that when
> 'standby' equipment is being installed, it comes
> with cost, weight and maintenance issues.
>
> Therefore, is it not useful to consider ways that
> standby equipment becomes smaller, lighter, less
> expensive and/or more efficient . . . if not
> eliminated all together? If one is unwilling to
> put a dip-stick into the energy contained in the
> ship's main battery . . . how is a standby battery
> going to be treated any differently?
>
> Bob . . .
>
Message 10
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| Subject: | Re: Please critique my electrical design |
>
>So....I'm betting that Mark meant he's measuring
>10.6V *after* 15 seconds of cranking, but with
>no/minimal load on the battery. Now, go back to
>the Corvette/Chevette example. If you accelerate
>the Corvette for 15 seconds, it'll still have
>400 HP, but you may only have 3 seconds of capacity (gas) left.=C2
The legacy LOAD TEST is an artifact carried
over from the automotive world. Automotive
load testers have a built in 15 second timer
that drives a light or perhaps a beeper.
Emacs!
Emacs!
Emacs!
When testing a battery, one starts the timer and then
cranks up the load knob to depress and hold voltage
at 9.0 volts. At the end of 15 seconds, you get a light
or a beep whereupon you read the current being delivered.
This is a 'cranking amps' kind of current and a figure of
merit for battery's suitability for continued service.
>Mark's test is even less valid if one has chosen
>a Lithium chemistry battery; their voltage has
>much less decline until it 'falls off the cliff' at full discharge.
Absolutely. The legacy lead-acid load test is
not applicable to lithium.
>The real test is monitoring *how long* voltage
>remains above the voltage that indicates
>complete discharge (which is around 10.5 V),
>while the typical load from the plane's required
>(endurance bus) electronics is applied.
Exactly. The load test numbers can give you a rough
idea of how the battery has degraded over time . . .
and tells you whether or not it will get your
engine going. But 8ut says NOTHING about capacity . . .
i.e. an ability to power ENDURANCE loads for the interval
you have established with design goals.
When the e-bus first appeared in OBAM aircraft,
a recommended design goal was to have electrical
endurance exceed fuel endurance. Obviously,
not a hard-n-fast rule but what every number
the builder chooses, it's really a pretty cool
thing to VERIFY that the number can be achieved.
There's a secondary benefit for replacing a
battery that fails to meet endurance requirements . . .
it's probably going to be replaced before its
cranking ability is seriously compromised. Hence,
exceedingly low probability of an off-home-base failure
of the battery.
Bob . . .
Message 11
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| Subject: | Re: Please critique my electrical design |
At 02:12 PM 4/11/2018, you wrote:
>Bob, thanks for reiterating the difference between a load test and a
>capacity test. Is there any possibility of gaining insight into a
>battery's capacity by studying the results of load testing?
Only very roughly . . . even then it's
something that needs to be conducted pretty
often and results TRACKED with time.
I've not conducted such testing so I
can't offer even a rough correlation
of capacity vs. load-test. But
I'm guessing it is roughly proportional.
If your brand new battery tested at
say 600A, then it's probably reaching
end of life when the load test falls to
400A . . . even tho it still cranks
the engine.
Bob . . .
Message 12
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| Subject: | Re: Car clock in an aircraft |
Typically, Real Time Clock ICs will have two power input pins, a primary and a
backup. For example, see the MCP7940N datasheet...
http://ww1.microchip.com/downloads/en/DeviceDoc/20005010F.pdf
...where you'll see that Pin 4 is for normal operating supply and Pin 3 is for
battery backup. Generally speaking, the battery is there only to keep timekeeping
underway if primary power is lost. It's not uncommon for all other functions
of the clock -- including time display -- to cease functioning when using
battery backup.
So, chances are good that if you power your automotive clock from a switched bus,
the coin cell will keep the clock accurate when the bus is turned off. You'll
know it's time to replace it when the clock doesn't keep time properly between
flights.
Eric
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=479280#479280
Message 13
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| Subject: | Re: Please critique my electrical design |
>> 10.6V *after* 15 seconds of cranking, but with no/minimal load on the bat
tery
Nope, The starter is the battery load tester. Continuously measure the vo
ltage while the starter is engaged. If the voltage drops below 10.6 volts w
hile cranking the battery needs to be charged and tested again. A health ba
ttery will return to 12 +volts after opening the starting circuit. Another p
iece of test gear is a an amp meter with amp shut between the negative termi
nal and battery post... (which I like better than the amp probe I use with t
he fluke 87) to test the health of the starter...say the load spikes to 250 a
mps to overcome the inertial mass of the rotating parts then drops to 125-15
0 amps...starter tests good.
The only other charging system health test is charging voltage... automotive
standards were 13.6 to 14.8 VDC...aircraft with solid state voltage regulat
or is 14.1 volts...I think.
Sent from my iPad
> On 11 Apr 2018, at 11:46 AM, Robert L. Nuckolls, III <nuckolls.bob@aeroele
ctric.com> wrote:
>
>>
>> So....I'm betting that Mark meant he's measuring 10.6V *after* 15 seconds
of cranking, but with no/minimal load on the battery. Now, go back to the C
orvette/Chevette example. If you accelerate the Corvette for 15 seconds, it'
ll still have 400 HP, but you may only have 3 seconds of capacity (gas) left
.=C3=82
>
> The legacy LOAD TEST is an artifact carried
> over from the automotive world. Automotive
> load testers have a built in 15 second timer
> that drives a light or perhaps a beeper.
>
> <27063fc.jpg>
>
>
> <270642b.jpg> <270643b.jpg>
>
>
> When testing a battery, one starts the timer and then
> cranks up the load knob to depress and hold voltage
> at 9.0 volts. At the end of 15 seconds, you get a light
> or a beep whereupon you read the current being delivered.
>
> This is a 'cranking amps' kind of current and a figure of
> merit for battery's suitability for continued service.
>
>> Mark's test is even less valid if one has chosen a Lithium chemistry batt
ery; their voltage has much less decline until it 'falls off the cliff' at f
ull discharge.
>
> Absolutely. The legacy lead-acid load test is
> not applicable to lithium.
>
>
>> The real test is monitoring *how long* voltage remains above the voltage t
hat indicates complete discharge (which is around 10.5 V), while the typical
load from the plane's required (endurance bus) electronics is applied.
>
> Exactly. The load test numbers can give you a rough
> idea of how the battery has degraded over time . . .
> and tells you whether or not it will get your
> engine going. But 8ut says NOTHING about capacity . . .
> i.e. an ability to power ENDURANCE loads for the interval
> you have established with design goals.
>
> When the e-bus first appeared in OBAM aircraft,
> a recommended design goal was to have electrical
> endurance exceed fuel endurance. Obviously,
> not a hard-n-fast rule but what every number
> the builder chooses, it's really a pretty cool
> thing to VERIFY that the number can be achieved.
>
> There's a secondary benefit for replacing a
> battery that fails to meet endurance requirements . . .
> it's probably going to be replaced before its
> cranking ability is seriously compromised. Hence,
> exceedingly low probability of an off-home-base failure
> of the battery.
>
>
> Bob . . .
Message 14
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| Subject: | Re: Please critique my electrical design |
Bob,
Thanks for the corrections.
nuckolls.bob(at)aeroelect wrote:
>
> The ovm14 can come out, that's built into the LR3.
Okay, thanks. I've corrected that in the latest version.
> If your using a fused bus, then the fusible link
> and remotely located field breaker stays in.
Just to make sure I'm following -- I'm placing the Alt Fld CB on a bus bar along
with three other CBs (Main Bus 2). In this case I don't need the fusible link,
correct? I've kept the fusible link between Main Bus 1 (fuses) and Main Bus
2 (CBs) because the distance is about 18".
> The G3X has its own low voltage sense, resolution
> and display feature. If you don't wish to use the
> separate light featured in the LR3C installation,
> just leave that terminal unused.
>
> YES! that is your bus voltage sense lead.
Thanks -- I removed the light and I'll use the G3X annunciator for LV, but I left
the terminal 3 feed with the 2A CB.
Bob . . .[/quote]
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=479282#479282
Message 15
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| Subject: | Re: Please critique my electrical design |
At 03:30 PM 4/11/2018, you wrote:
>>>10.6V *after* 15 seconds of cranking, but with no/minimal load on
>>>the battery
>Nope, The starter is the battery load tester. Continuously
>measure the voltage while the starter is engaged. If the voltage
>drops below 10.6 volts while cranking the battery needs to be
>charged and tested again. A health battery will return to 12 +volts
>after opening the starting circuit. Another piece of test gear is a
>an amp meter with amp shut between the negative terminal and battery
>post... (which I like better than the amp probe I use with the fluke
>87) to test the health of the starter...say the load spikes to 250
>amps to overcome the inertial mass of the rotating parts then drops
>to 125-150 amps...starter tests good.
>The only other charging system health test is charging voltage...
>automotive standards were 13.6 to 14.8 VDC...aircraft with solid
>state voltage regulator is 14.1 volts...I think.
Meaningful data confirming battery condition
is hard to come by. Variation in starter draw
due to the modulated torque loads presented
by reciprocating pistons produces a wildly
unstable value on an analog meter . . . and
can drive many digital displays nuts.
I've done energy demand studies using fast
data acquisition systems that sample several
hundred times per second combined with
'integration by parts' software that
yields very stable numbers.
But just as in most vehicles, a flagging starter
battery will make it's condition known because
of how it sounds . . . and the bottom line for
cranking demands only that the engine got going
yet one more time.
A battery that's demonstrating decreased
starter performance may already have sagged
below the ca[acotu for continued service as set by
design goals.
Bob . . .
Message 16
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| Subject: | Re: Please critique my electrical design |
Anecdotally:
I replaced the 60Ah battery of the Ford Mondeo in preparation for a
skiing trip.
It wouldn't take more than an 18 Ah charge from empty. It still cranked
fine.
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