Today's Message Index:
----------------------
1. 08:21 AM - Re: RG Batteries: I learned something last night (Ken)
2. 12:43 PM - Re: AeroElectric-List Digest: 18 Msgs - 10/27/11 (kent@cybermesa.com)
3. 06:42 PM - Re: AeroElectric-List Digest: 18 Msgs - 10/27/11 (Robert L. Nuckolls, III)
4. 06:55 PM - Re: RG Batteries: I learned something last night (Robert L. Nuckolls, III)
5. 10:05 PM - Re: RG Batteries: I learned something last night (Ed Holyoke)
Message 1
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| Subject: | Re: RG Batteries: I learned something last night |
I can report results that seem similar. For a new 9AH dekka vrla battery
discharged at 6 amps (2 ohm resistance) I measure 56 minutes to 11.00
volts or 5.6 AH.
For a 6+ year old but 5 years in service identical battery (420 flight
hours) that has never been deep discharged or been on a maintainer, I
measure 52 minutes to 11.00 volts or 5.2 AH again at 6 amps discharge
rate. All tests were done with the battery stabilized at a 66*F basement
room temperature for several days after top up with a Schumaker 1162.
I don't have an easy way to compare the cranking capabilities other than
last winter the two paralleled batts in my Z-14 system seemed to crank a
bit slower than normal. It cranked fine all summer but I have just
replaced the oldest battery anyway. Hasn't been much colder than
freezing yet to compare this winter. I too am surprised that the old
battery delivered 93% of the capacity of the newer one at a 6 amp
discharge rate.
I'll attempt to compare the current flow from each battery while
cranking (clamp on dc ammeter) the next time I fly. (I have the
automatic parallel option during cranking). Should give an indication of
how another 4 year in service batt compares to the new one for cranking.
Ken
On 29/10/2011 11:25 AM, Robert L. Nuckolls, III wrote:
> <nuckolls.bob@aeroelectric.com>
>
> That bench test battery I featured in a posting
> a few days ago had not be cap-checked in several years.
> The thing is over ten years old and has yielded a
> great return on investment.
>
> I did a load test on this battery about a week ago.
> It dumped about 300A for 15 seconds at the 70F mark
> on the load meter. A value that is less than 1/2 the
> as-new capability.
>
> Just for grins, I pulled out the CBAII battery tester.
> The bench battery had been on a maintainer for a couple days.
>
> I did a 6A discharge test. The value I use as exemplary
> of most of my instrumentation experiments. The battery
> delivered 24+ a.h. of useful energy! Going to the
> factory data on this battery we see:
>
> http://www.aeroelectric.com/Pictures/Curves/33AH_12V_Capacity_vs_Load.gif
>
>
> The factory says a 6.6A load will deplete this battery
> in about 4 hours . . . or 24+ a.h.
>
> In years past, my teachers modeled the battery as a large
> array of cells connected in a series-parallel configuration
> with EACH cell offering some finite energy value combined
> with it's own source impedance. If you loose 1/2 the cell
> in the full-up array, energy drops by 1/2 but source impedance
> doubles.
>
> This experiment last night showed that while the source
> impedance for the battery had doubled (1/2 the cranking
> snort), the total energy available was still almost as-new!
> This means that the gazillion itty-bitty cell analogy is not
> quite accurate. Those cells can experience a rise in
> source impedance while still offering their original
> energy capability.
>
> This battery as-new will deliver 9V at over 800A for
> 15 seconds. This suggests a source impedance of
> (12-9)/800 = .004 ohms. It now produces about 300A
> so the new source impedance is (12-9)/300 = .010
> ohms.
>
> So while the impedance has doubled, the available
> energy at 6A loading has been barely affected . . . if
> at all. A rise from .004 to .010 ohms source impedance
> has little influence on a test load of (12/6)= 2 Ohms.
>
> This argues with any analogy that suggests a "dead"
> micro-cell in a battery becomes totally disconnected
> from the array. It suggests that individual cells
> can demonstrate an ability to store and regurgitate
> energy while experiencing an independent and unrelated
> rise in source impedance.
>
> This discovery suggests that it is possible for a
> battery to meet battery-only-ops requirements while
> demonstrating reduced cranking performance. This ol'
> dog is still learning . . . and my grey haired bench
> test battery is still in service.
>
Message 2
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| Subject: | Re: AeroElectric-List Digest: 18 Msgs - 10/27/11 |
U
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Total Messages Posted Thu 10/27/11: 18
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Today's Message Index:
----------------------
1. 06:24 AM - Re: Z16 voltage concern (Robert L. Nuckolls, III)
2. 06:40 AM - Incandescent lamps in Wig-Wag systems (OOPS) (Robert L. Nuckolls,
III)
3. 06:56 AM - Re: Z16 voltage concern (Sam Marlow)
4. 07:48 AM - Re: Z16 voltage concern (Jared Yates)
5. 08:40 AM - Re: Z16 voltage concern (Robert L. Nuckolls, III)
6. 08:59 AM - Re: Z16 voltage concern ()
7. 09:03 AM - Re: Z16 voltage concern ()
8. 09:43 AM - Re: Z16 voltage concern (Jay Hyde)
9. 10:33 AM - Re: Z16 voltage concern (user9253)
10. 10:34 AM - Re: Z16 voltage concern (Robert L. Nuckolls, III)
11. 11:05 AM - Re: Re: Z16 voltage concern ()
12. 01:53 PM - AeroLeds (Robert L. Nuckolls, III)
13. 01:53 PM - Canopy Switch (user9253)
14. 04:24 PM - Audio Design (messydeer)
15. 04:47 PM - Re: Audio Design (Michael Welch)
16. 04:52 PM - Re: Audio Design (Michael Welch)
17. 04:57 PM - Re: AeroLeds (James Kilford)
18. 10:04 PM - Re: Audio Design (messydeer)
________________________________ Message 1 _____________________________________
Time: 06:24:54 AM PST US
From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
Subject: RE: AeroElectric-List: Z16 voltage concern
At 01:41 AM 10/27/2011, you wrote:
>Hello Les,
>
>
>The problem comes from the diode between the Main Bus and the
>Endurance bus; the forward voltage drop across this diode leaves you
>with the lower voltage at the Endurance bus. When you put the
>alternate feed on to the Endurance bus you 'boost' boost the voltage
>because there is no diode in the alternate path. If you use a
>Schottkey diode instead of a normal diode between the Main and
>Endurance bus the Endurance bus voltage will be better as the
>forward voltage drop across a Schottkey is less than that of a
>normal diode, but you will always have a slightly lower voltage on
>the Endurance bus.
>
>Jay
My face is red. I should also have asked where you
measured the system voltage. If measured on the e-bus
in normal ops mode, the voltage will be a bit lower than
the main bus . . . which doesn't matter.
Recall that when the alternator is running and carrying
all operating loads, the target voltage for the battery
and main bus is 14.2 to 14.6 volts. This is the nominal
supply necessary to top off your battery after an engine
start.
The e-bus, being fed through the diode WILL be down around
13.5 to 13.8 which is okay. Recall also that while a
battery CHARGES at 14.2 to 14.6, it DELIVERS energy
at 12.5 volts and BELOW . . . when it gets down to 10.5
volts, the battery is used up.
If your e-bus accessories are chosen for their usefulness
as aids to battery-only ops, then they're EXPECTED to
perform over the battery only voltage range of 10.5 to
12.5 volts. Hence a normal e-bus voltage of 13.5 presents no
issues of concern.
If your low voltage warning is built into an accessory
attached to the e-bus, then it needs to trigger at
some level which accommodates the diode drop. 12.8
volts is about right. If it is not user adjustable,
then perhaps it should be disabled and a separate,
standalone, LV warning set for 13.0 volts be driven
from the MAIN bus.
Finally, if push comes to shove, there's no sin in
leaving the e-bus alternate feed switch closed during
normal operations. The diode is there to prevent back-
feeding the main bus should you find it necessary to
revert to battery only operations.
Sorry for the fire-drill.
Bob . . .
________________________________ Message 2 _____________________________________
Time: 06:40:13 AM PST US
From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
Subject: AeroElectric-List: Incandescent lamps in Wig-Wag systems (OOPS)
A sharp eyed reader pointed out that I cited the wrong
plot for a close look at inrush on the 55w lamp. The corrected
citation has been substituted in the mini-essay below:
At 10:30 AM 10/26/2011, you wrote:
<nuckolls.bob@aeroelectric.com>
A few weeks ago I was called to task for some
demonstrably sloppy data gathering when we were
discussing inrush limiting on incandescent lamps
used in wig-wag recognition systems. The plot I'd
published at:
http://www.aeroelectric.com/Pictures/Curves/Wig_Wag_Currents.jpg
. . . was properly identified as somewhat 'fuzzy' and
not properly supportive of some estimates of the cold
start inrush values. I ran across my little po' boy's
solid state switch yesterday so I drug it to the bench
and set up the following experiment:
http://aeroelectric.com/Pictures/Schematics/Test_Set-Up_Picture.jpg
http://aeroelectric.com/Pictures/Schematics/Test_Set-Up_Schematic.jpg
I ran some data plots with a 1 ohm resistor-load in place
of the lamp. Here we observe the expected current flow
plotted at scan speeds that will display 3-4 wig-wag cycles.
http://www.aeroelectric.com/Pictures/Curves/1-OHM_250mS.jpg
Then I zoomed in on an exemplar ON transition . . .
http://www.aeroelectric.com/Pictures/Curves/1-OHM_50uS.jpg
. . . and we see that the 'probe' connection is a tad
bit over-damped as indicated by the rounding at the upper
corner of the rise.
I then replaced the load resistor with a 55w halogen
head lamp bulb and produced this plot of wig-wag
currents:
http://www.aeroelectric.com/Pictures/Curves/55W%20WIGWAG.jpg
Here we see the effects of lamp temperature on the inrush
and running currents. At turn on, the lamp was cool enough
to produce about a 9A spike. The measured current just
before turn-off was on the order of 5A.
Inrush current from a cold start is determined by total
loop resistance of the wiring, battery source impedance,
and lamp cold resistance. The lamp has a measured cold
resistance of 145 milliohms. If driven by a zero-ohms
source at 12v, the theoretical inrush would be
12/.134 = 83 amps. A slow sweep (1 mS/Div) peek at a
cold start in this test setup yielded the following trace:
http://www.aeroelectric.com/Pictures/Curves/55W_COLD-START_1mS.jpg
Here we see a measured inrush on the order of 42 amps.
This suggests that wiring and battery resistances added
another 140 milliohms or so to the loop resistance.
Zooming in for a closer peek at the cold start . . .
(Corrected image citation)
http://www.aeroelectric.com/Pictures/Curves/55W_COLD-START_50uS.jpg
we see the same 42A displayed value for peak current.
Further, there is still more rounding of the plot as
compared with the almost purely resistive plot cited
above.
Exploration of lamp behavior during turn-on could not
be conducted with a mechanical switch or relay. Contact
bounce during turn-on would badly contaminate the data.
The solid state switch driven by a function generator
suffers no such shortcomings.
The closer look confirms that my original suppositions
for inrush on the trashy trace were correct. The earlier
plot was made with longer wires than for this experiment
hence we saw a 32A cold start inrush as opposed to 42A
in this case. It also confirms that the dynamics for rate of
rise and peak currents are limited by system wiring
(resistance and inductance) and there were no erroneous
observations limited by oscilloscope sample rates.
This experiment supports my original assertions that
turn-on transitions during wig-wag operations are a small
fraction (about 25%) of the initial cold-start value.
Bob . . .
________________________________ Message 3 _____________________________________
Time: 06:56:43 AM PST US
From: Sam Marlow <sam.marlow@roadrunner.com>
Subject: Re: AeroElectric-List: Z16 voltage concern
Just wondered where I could find a Schottkey bridge to bring my voltage
back up close to normal?
Thanks,
Sam
Robert L. Nuckolls, III wrote:
> <nuckolls.bob@aeroelectric.com>
>
> At 01:41 AM 10/27/2011, you wrote:
>
>> Hello Les,
>>
>>
>>
>> The problem comes from the diode between the Main Bus and the
>> Endurance bus; the forward voltage drop across this diode leaves you
>> with the lower voltage at the Endurance bus. When you put the
>> alternate feed on to the Endurance bus you 'boost' boost the voltage
>> because there is no diode in the alternate path. If you use a
>> Schottkey diode instead of a normal diode between the Main and
>> Endurance bus the Endurance bus voltage will be better as the forward
>> voltage drop across a Schottkey is less than that of a normal diode,
>> but you will always have a slightly lower voltage on the Endurance bus.
>>
>> Jay
>
> My face is red. I should also have asked where you
> measured the system voltage. If measured on the e-bus
> in normal ops mode, the voltage will be a bit lower than
> the main bus . . . which doesn't matter.
>
> Recall that when the alternator is running and carrying
> all operating loads, the target voltage for the battery
> and main bus is 14.2 to 14.6 volts. This is the nominal
> supply necessary to top off your battery after an engine
> start.
>
> The e-bus, being fed through the diode WILL be down around
> 13.5 to 13.8 which is okay. Recall also that while a
> battery CHARGES at 14.2 to 14.6, it DELIVERS energy
> at 12.5 volts and BELOW . . . when it gets down to 10.5
> volts, the battery is used up.
>
> If your e-bus accessories are chosen for their usefulness
> as aids to battery-only ops, then they're EXPECTED to
> perform over the battery only voltage range of 10.5 to
> 12.5 volts. Hence a normal e-bus voltage of 13.5 presents no
> issues of concern.
>
> If your low voltage warning is built into an accessory
> attached to the e-bus, then it needs to trigger at
> some level which accommodates the diode drop. 12.8
> volts is about right. If it is not user adjustable,
> then perhaps it should be disabled and a separate,
> standalone, LV warning set for 13.0 volts be driven
> from the MAIN bus.
>
> Finally, if push comes to shove, there's no sin in
> leaving the e-bus alternate feed switch closed during
> normal operations. The diode is there to prevent back-
> feeding the main bus should you find it necessary to
> revert to battery only operations.
>
> Sorry for the fire-drill.
>
> Bob . . .
>
>
________________________________ Message 4 _____________________________________
Time: 07:48:52 AM PST US
Subject: Re: AeroElectric-List: Z16 voltage concern
From: Jared Yates <email@jaredyates.com>
Bob sells a nice package on the aeroelectric connection website. I
installed his system and subsequently cooked the diode due to improper
insulation in my mounting, and I was able to find the diode itself
online separately for a few dollars. I would recommend Bob's package
since it has the circuit board and mounting hardware ready to go.
On Thu, Oct 27, 2011 at 9:53 AM, Sam Marlow <sam.marlow@roadrunner.com> wrote:
> <sam.marlow@roadrunner.com>
>
> Just wondered where I could find a Schottkey bridge to bring my voltage back
> up close to normal?
> Thanks,
> Sam
>
> Robert L. Nuckolls, III wrote:
>>
>> <nuckolls.bob@aeroelectric.com>
>>
>> At 01:41 AM 10/27/2011, you wrote:
>>
>>> Hello Les,
>>>
>>>
>>>
>>> The problem comes from the diode between the Main Bus and the Endurance
>>> bus; the forward voltage drop across this diode leaves you with the lower
>>> voltage at the Endurance bus. When you put the alternate feed on to the
>>> Endurance bus you 'boost' boost the voltage because there is no diode in the
>>> alternate path. If you use a Schottkey diode instead of a normal diode
>>> between the Main and Endurance bus the Endurance bus voltage will be better
>>> as the forward voltage drop across a Schottkey is less than that of a normal
>>> diode, but you will always have a slightly lower voltage on the Endurance
>>> bus.
>>>
>>> Jay
>>
>> My face is red. I should also have asked where you
>> measured the system voltage. If measured on the e-bus
>> in normal ops mode, the voltage will be a bit lower than
>> the main bus . . . which doesn't matter.
>>
>> Recall that when the alternator is running and carrying
>> all operating loads, the target voltage for the battery
>> and main bus is 14.2 to 14.6 volts. This is the nominal
>> supply necessary to top off your battery after an engine
>> start.
>>
>> The e-bus, being fed through the diode WILL be down around
>> 13.5 to 13.8 which is okay. Recall also that while a
>> battery CHARGES at 14.2 to 14.6, it DELIVERS energy
>> at 12.5 volts and BELOW . . . when it gets down to 10.5
>> volts, the battery is used up.
>>
>> If your e-bus accessories are chosen for their usefulness
>> as aids to battery-only ops, then they're EXPECTED to
>> perform over the battery only voltage range of 10.5 to
>> 12.5 volts. Hence a normal e-bus voltage of 13.5 presents no
>> issues of concern.
>>
>> If your low voltage warning is built into an accessory
>> attached to the e-bus, then it needs to trigger at
>> some level which accommodates the diode drop. 12.8
>> volts is about right. If it is not user adjustable,
>> then perhaps it should be disabled and a separate,
>> standalone, LV warning set for 13.0 volts be driven
>> from the MAIN bus.
>>
>> Finally, if push comes to shove, there's no sin in
>> leaving the e-bus alternate feed switch closed during
>> normal operations. The diode is there to prevent back-
>> feeding the main bus should you find it necessary to
>> revert to battery only operations.
>>
>> Sorry for the fire-drill.
>>
>> Bob . . .
>>
>>
>>
>>
>>
>
>
________________________________ Message 5 _____________________________________
Time: 08:40:45 AM PST US
From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
Subject: Re: AeroElectric-List: Z16 voltage concern
At 08:53 AM 10/27/2011, you wrote:
><sam.marlow@roadrunner.com>
>
>Just wondered where I could find a Schottkey bridge to bring my
>voltage back up close to normal?
>Thanks,
Why are you worried about it? Given the physics of
how the system is designed, 13.5 IS normal.
The standard rectifier bridge will give you a drop
of about .7 volts for a 10A e-bus load. The Schottky
device will drop that to about .5 volts. Not a
great difference.
The acid test is to operate your airplane for a time
with the e-bus alt feed switch open, and then for
a time with it closed. Were it not for a reading on
a display, would you know the difference?
Know that bus isolation diodes are used on large
aircraft. While these are usually 28 volt systems
were the diode drop represents a smaller percentage
of loss . . . the drop is noted, evaluated and found
insignificant to normal operations of devices down-
stream of the diode.
I suggest that such is the case here as well.
Bob . . .
________________________________ Message 6 _____________________________________
Time: 08:59:03 AM PST US
From: <sam.marlow@roadrunner.com>
Subject: Re: AeroElectric-List: Z16 voltage concern
I'm aware of the Schottkey diode board but that's not a bridge. I need two sources
in to feed my aux buss, so no switching is required. I have this setup now,
but it drops the voltage to the 12v range, with the Radio Shack bridge setup.
---- Jared Yates <email@jaredyates.com> wrote:
===========
Bob sells a nice package on the aeroelectric connection website. I
installed his system and subsequently cooked the diode due to improper
insulation in my mounting, and I was able to find the diode itself
online separately for a few dollars. I would recommend Bob's package
since it has the circuit board and mounting hardware ready to go.
On Thu, Oct 27, 2011 at 9:53 AM, Sam Marlow <sam.marlow@roadrunner.com> wrote:
> <sam.marlow@roadrunner.com>
>
> Just wondered where I could find a Schottkey bridge to bring my voltage back
> up close to normal?
> Thanks,
> Sam
>
> Robert L. Nuckolls, III wrote:
>>
>> <nuckolls.bob@aeroelectric.com>
>>
>> At 01:41 AM 10/27/2011, you wrote:
>>
>>> Hello Les,
>>>
>>>
>>>
>>> The problem comes from the diode between the Main Bus and the Endurance
>>> bus; the forward voltage drop across this diode leaves you with the lower
>>> voltage at the Endurance bus. When you put the alternate feed on to the
>>> Endurance bus you 'boost' boost the voltage because there is no diode in the
>>> alternate path. If you use a Schottkey diode instead of a normal diode
>>> between the Main and Endurance bus the Endurance bus voltage will be better
>>> as the forward voltage drop across a Schottkey is less than that of a normal
>>> diode, but you will always have a slightly lower voltage on the Endurance
>>> bus.
>>>
>>> Jay
>>
>> My face is red. I should also have asked where you
>> measured the system voltage. If measured on the e-bus
>> in normal ops mode, the voltage will be a bit lower than
>> the main bus . . . which doesn't matter.
>>
>> Recall that when the alternator is running and carrying
>> all operating loads, the target voltage for the battery
>> and main bus is 14.2 to 14.6 volts. This is the nominal
>> supply necessary to top off your battery after an engine
>> start.
>>
>> The e-bus, being fed through the diode WILL be down around
>> 13.5 to 13.8 which is okay. Recall also that while a
>> battery CHARGES at 14.2 to 14.6, it DELIVERS energy
>> at 12.5 volts and BELOW . . . when it gets down to 10.5
>> volts, the battery is used up.
>>
>> If your e-bus accessories are chosen for their usefulness
>> as aids to battery-only ops, then they're EXPECTED to
>> perform over the battery only voltage range of 10.5 to
>> 12.5 volts. Hence a normal e-bus voltage of 13.5 presents no
>> issues of concern.
>>
>> If your low voltage warning is built into an accessory
>> attached to the e-bus, then it needs to trigger at
>> some level which accommodates the diode drop. 12.8
>> volts is about right. If it is not user adjustable,
>> then perhaps it should be disabled and a separate,
>> standalone, LV warning set for 13.0 volts be driven
>> from the MAIN bus.
>>
>> Finally, if push comes to shove, there's no sin in
>> leaving the e-bus alternate feed switch closed during
>> normal operations. The diode is there to prevent back-
>> feeding the main bus should you find it necessary to
>> revert to battery only operations.
>>
>> Sorry for the fire-drill.
>>
>> Bob . . .
>>
>>
>>
>>
>>
>
>
________________________________ Message 7 _____________________________________
Time: 09:03:56 AM PST US
From: <sam.marlow@roadrunner.com>
Subject: Re: AeroElectric-List: Z16 voltage concern
Your right Bob, I just wanted see normal, or as close to normal, as possible. It's
a good dignastic tool. Is it possible to construct my own bridge using Schottkey
diode's, or is that silly?
---- "Robert L. Nuckolls wrote:
===========
At 08:53 AM 10/27/2011, you wrote:
><sam.marlow@roadrunner.com>
>
>Just wondered where I could find a Schottkey bridge to bring my
>voltage back up close to normal?
>Thanks,
Why are you worried about it? Given the physics of
how the system is designed, 13.5 IS normal.
The standard rectifier bridge will give you a drop
of about .7 volts for a 10A e-bus load. The Schottky
device will drop that to about .5 volts. Not a
great difference.
The acid test is to operate your airplane for a time
with the e-bus alt feed switch open, and then for
a time with it closed. Were it not for a reading on
a display, would you know the difference?
Know that bus isolation diodes are used on large
aircraft. While these are usually 28 volt systems
were the diode drop represents a smaller percentage
of loss . . . the drop is noted, evaluated and found
insignificant to normal operations of devices down-
stream of the diode.
I suggest that such is the case here as well.
Bob . . .
________________________________ Message 8 _____________________________________
Time: 09:43:26 AM PST US
From: "Jay Hyde" <jay@horriblehyde.com>
Subject: RE: AeroElectric-List: Z16 voltage concern
I could tell you where to find it in South Africa! :-)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
HH Enterprises
Aircraft assembly, repair, wiring and avionics
Flight instruction
General and Electrical Engineering services
(NHD Elec Eng, BTech Elec Eng, GDE ELec Eng)
Great dinner parties and conversation
General adventuring, climbing, kayaking and living
Blog: www.rawhyde.wordpress.com
Cel: 083300 8675
Email: jay@horriblehyde.com
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Sam
Marlow
Sent: 27 October 2011 03:53 PM
Subject: Re: AeroElectric-List: Z16 voltage concern
<sam.marlow@roadrunner.com>
Just wondered where I could find a Schottkey bridge to bring my voltage
back up close to normal?
Thanks,
Sam
Robert L. Nuckolls, III wrote:
> <nuckolls.bob@aeroelectric.com>
>
> At 01:41 AM 10/27/2011, you wrote:
>
>> Hello Les,
>>
>>
>>
>> The problem comes from the diode between the Main Bus and the
>> Endurance bus; the forward voltage drop across this diode leaves you
>> with the lower voltage at the Endurance bus. When you put the
>> alternate feed on to the Endurance bus you 'boost' boost the voltage
>> because there is no diode in the alternate path. If you use a
>> Schottkey diode instead of a normal diode between the Main and
>> Endurance bus the Endurance bus voltage will be better as the forward
>> voltage drop across a Schottkey is less than that of a normal diode,
>> but you will always have a slightly lower voltage on the Endurance bus.
>>
>> Jay
>
> My face is red. I should also have asked where you
> measured the system voltage. If measured on the e-bus
> in normal ops mode, the voltage will be a bit lower than
> the main bus . . . which doesn't matter.
>
> Recall that when the alternator is running and carrying
> all operating loads, the target voltage for the battery
> and main bus is 14.2 to 14.6 volts. This is the nominal
> supply necessary to top off your battery after an engine
> start.
>
> The e-bus, being fed through the diode WILL be down around
> 13.5 to 13.8 which is okay. Recall also that while a
> battery CHARGES at 14.2 to 14.6, it DELIVERS energy
> at 12.5 volts and BELOW . . . when it gets down to 10.5
> volts, the battery is used up.
>
> If your e-bus accessories are chosen for their usefulness
> as aids to battery-only ops, then they're EXPECTED to
> perform over the battery only voltage range of 10.5 to
> 12.5 volts. Hence a normal e-bus voltage of 13.5 presents no
> issues of concern.
>
> If your low voltage warning is built into an accessory
> attached to the e-bus, then it needs to trigger at
> some level which accommodates the diode drop. 12.8
> volts is about right. If it is not user adjustable,
> then perhaps it should be disabled and a separate,
> standalone, LV warning set for 13.0 volts be driven
> from the MAIN bus.
>
> Finally, if push comes to shove, there's no sin in
> leaving the e-bus alternate feed switch closed during
> normal operations. The diode is there to prevent back-
> feeding the main bus should you find it necessary to
> revert to battery only operations.
>
> Sorry for the fire-drill.
>
> Bob . . .
>
>
________________________________ Message 9 _____________________________________
Time: 10:33:27 AM PST US
Subject: AeroElectric-List: Re: Z16 voltage concern
From: "user9253" <fran4sew@banyanol.com>
> Is it possible to construct my own bridge using Schottkey diode's, or is that
silly?
The advantage of using a diode bridge with mounting hole in the center is its mechanical
robustness. Two discrete diodes will function electrically just as
well, as long as they are mounted securely for mechanical strength and heat dissipation.
If it is desired to boost the voltage output from the Rotax regulator from 13.5
to 14, a Schottky diode could be put in series with the wire going to the regulator
"C" terminal (arrow pointing towards the regulator). I have not actually
done that but it should work.
My Rotax voltage regulator puts out 13.6 volts. That might not be enough to
top off a discharged battery, but the engine starts so quickly that it does not
get run down much. I connect a battery maintainer when not flying. Everything
works fine so I have not tried to boost the regulator voltage.
Joe
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=356109#356109
________________________________ Message 10 ____________________________________
Time: 10:34:56 AM PST US
From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
Subject: Re: AeroElectric-List: Z16 voltage concern
At 11:00 AM 10/27/2011, you wrote:
>
>Your right Bob, I just wanted see normal, or as close to normal, as
>possible. It's a good dignastic tool. Is it possible to construct my
>own bridge using Schottkey diode's, or is that silly?
Not at all. I selected the single hole, potted 'brick'
of plastic with 4 diodes for it's simplicity of mounting,
no insulation needed, and fast-on tabs. In most applications
we used only one of the four diodes . . . the other three
were not 'in the way' of successful exploitation of other
features for the device.
If you only need one diode, then there's a host of
offerings from the electronics suppliers. There are
a number of dual Shottky devices that feature two
diodes in the single package. Here's one example:
http://tinyurl.com/4x87a6s
This particular device does need to be insulated
from its heat-sinking surface like so . . .
http://www.aeroelectric.com/Catalog/AEC/9001
Bob . . .
________________________________ Message 11 ____________________________________
Time: 11:05:19 AM PST US
From: <sam.marlow@roadrunner.com>
Subject: Re: AeroElectric-List: Re: Z16 voltage concern
Thanks!
---- user9253 <fran4sew@banyanol.com> wrote:
===========
> Is it possible to construct my own bridge using Schottkey diode's, or is that
silly?
The advantage of using a diode bridge with mounting hole in the center is its mechanical
robustness. Two discrete diodes will function electrically just as
well, as long as they are mounted securely for mechanical strength and heat dissipation.
If it is desired to boost the voltage output from the Rotax regulator from 13.5
to 14, a Schottky diode could be put in series with the wire going to the regulator
"C" terminal (arrow pointing towards the regulator). I have not actually
done that but it should work.
My Rotax voltage regulator puts out 13.6 volts. That might not be enough to
top off a discharged battery, but the engine starts so quickly that it does not
get run down much. I connect a battery maintainer when not flying. Everything
works fine so I have not tried to boost the regulator voltage.
Joe
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=356109#356109
________________________________ Message 12 ____________________________________
Time: 01:53:20 PM PST US
From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
Subject: AeroElectric-List: AeroLeds
A few weeks ago there was some discussion on the List about
noises from some AeroLed products. I cruised their website and
promised to inquire into the marketing philosophy for their
lighting products.
I had some good conversation with one of the principals,
a Mr. Nate Calvin. These guys are not the new kids on the
block. They've delivered product to some very sophisticated
customers who would demand careful scrutiny of mechanical
and electrical characteristics. Nate tells me that all
their product meets or exceeds DO-160 requirements for
conducted noise in small aircraft.
I'll remind readers that passing all the tests does not
mean ZERO noise emissions . . . only that they are below
the industry approved limits for this an all other electronics
offered to the type certificated aircraft market.
He recalled one case where an observed noise problem
turned out to be a design problem with an intercom
that was not fully vetted for living in the DO-160
world of light aircraft.
Bottom line is that AeroLed products are very low
risk for contributing to a noise issue. When they
are identified as an observable noise source, the
investigator should consider poor design of the victim
system and/or some form of installation error first.
Bob . . .
________________________________ Message 13 ____________________________________
Time: 01:53:21 PM PST US
Subject: AeroElectric-List: Canopy Switch
From: "user9253" <fran4sew@banyanol.com>
A canopy-open indicator light does not help much to remind the pilot to latch the
canopy. The pilot will become accustomed to seeing that light on while she
taxies, trying to keep cool with the canopy open. What is needed is an audio
and visual alarm that ONLY activates if the canopy is not latched for takeoff.
I thought about using a microprocessor but am not proficient at programming.
Then I found this LM2907 "RPM Speed Switch". Although it requires a few resistors
and capacitors, all of the active components are contained in one 8-pin
IC.
Here is a proposed circuit: https://lh5.googleusercontent.com/-fI7pwRbufgI/Tqm5F18UY5I/AAAAAAAAAcw/QWs0GHx4q1I/s800/Canopy%252520Alarm.gif
And here is the datasheet for the LM2907: http://www.national.com/ds/LM/LM2907.pdf
Joe
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=356119#356119
Attachments:
http://forums.matronics.com//files/canopy_alarm_272.gif
________________________________ Message 14 ____________________________________
Time: 04:24:06 PM PST US
Subject: AeroElectric-List: Audio Design
From: "messydeer" <messydeer@yahoo.com>
Hi!
I haven't yet bought any communication devices for my Sonex. I plan to get a COM
radio, intercom, a couple headsets, and a couple PTT switches. I've got an MGL
Enigma EFIS that can transmit audio warnings that I'd like to wire into the
system. I'd also like to wire in an external audio device, like my cell phone
which has an MP3 player and maybe an AM/FM radio or tablet computer. I think
I'll pass on the DVD player.
My goal is to get something that's dependable and affordable with an eye towards
upgrading. Suggestions on what to get and how to wire these guys would be helpful.
Thanks :-)
--------
Dan
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=356135#356135
________________________________ Message 15 ____________________________________
Time: 04:47:45 PM PST US
From: Michael Welch <mdnanwelch7@hotmail.com>
Subject: Re: AeroElectric-List: Audio Design
Dan,
I sure do like Icom products! An Icom IC210 would make a great com radio(or
even an IC200). It's super easy to hard-wire an intercom to,
which is what I did, or if I'm not mistaken, the IC210 may even have a built-in
intercom (2 place).
I needed the rubber "knob condoms" on my older IC200, (they dried out and cracked
off) and when I told the parts
guy what I needed he just sent them to me for FREE!!! They even paid for the shipping.
I like Icom.
Mike Welch
> Suggestions on what to get and how to wire these guys would be helpful.
>
> Thanks :-)
>
> --------
> Dan
________________________________ Message 16 ____________________________________
Time: 04:52:31 PM PST US
From: Michael Welch <mdnanwelch7@hotmail.com>
Subject: Re: AeroElectric-List: Audio Design
Dan,
Like this one:
http://www.ebay.com/itm/Avionics-Icom-ICA210-IC-A210-VHF-Communication-Radio-/330614367526?pt=Motors_Aviation_Parts_Gear&vxp=mtr&hash=item4cfa26e526#ht_500wt_754
I see I messed up the model #. It was supposed to be IC "A"210. It's been
many months since I was working with the radios.
Mike
________________________________ Message 17 ____________________________________
Time: 04:57:51 PM PST US
Subject: Re: AeroElectric-List: AeroLeds
From: James Kilford <james@etravel.org>
Interesting stuff there Bob.
On 27 October 2011 21:47, Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> nuckolls.bob@aeroelectric.com**>
>
> A few weeks ago there was some discussion on the List about
> noises from some AeroLed products. I cruised their website and
> promised to inquire into the marketing philosophy for their
> lighting products.
>
> I had some good conversation with one of the principals,
> a Mr. Nate Calvin. These guys are not the new kids on the
> block. They've delivered product to some very sophisticated
> customers who would demand careful scrutiny of mechanical
> and electrical characteristics. Nate tells me that all
> their product meets or exceeds DO-160 requirements for
> conducted noise in small aircraft.
>
> I'll remind readers that passing all the tests does not
> mean ZERO noise emissions . . . only that they are below
> the industry approved limits for this an all other electronics
> offered to the type certificated aircraft market.
>
> He recalled one case where an observed noise problem
> turned out to be a design problem with an intercom
> that was not fully vetted for living in the DO-160
> world of light aircraft.
>
> Bottom line is that AeroLed products are very low
> risk for contributing to a noise issue. When they
> are identified as an observable noise source, the
> investigator should consider poor design of the victim
> system and/or some form of installation error first.
>
>
> Bob . . .
>
>
________________________________ Message 18 ____________________________________
Time: 10:04:54 PM PST US
Subject: AeroElectric-List: Re: Audio Design
From: "messydeer" <messydeer@yahoo.com>
Thanks, Mike.
I've heard ICOM makes quality stuff. But it's a bit big, both in price and size.
I just realized MGL has an intercom in their V10 radio. They're also releasing
soon their newer version, the V6. Reports say these intercoms actually work
well, as opposed to earlier combo units of a different technology from other
manufacturers. They'll be around $1000.
If I go this route, it also simplifies things. Just connect the wires according
to their diagrams. I got a little experience making a Dsub harness a few months
ago, so I should be set.
--------
Dan
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=356155#356155
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| Subject: | Re: AeroElectric-List Digest: 18 Msgs - 10/27/11 |
At 02:36 PM 10/30/2011, you wrote:
Kent, you are obviously subscribed to the digest
version of the List which given you one email per
day of all the membership's postings.
When you 'reply' to any particular posting, you
need to trim away all irrelevant messages else your
reply is perhaps dozens of messages long and your
readers will have trouble knowing which message
prompted your response.
Bob . . .
////
(o o)
===========o00o=(_)=o00o========
< Go ahead, make my day . . . >
< show me where I'm wrong. >
================================
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| Subject: | Re: RG Batteries: I learned something last night |
At 10:18 AM 10/30/2011, you wrote:
I can report results that seem similar. For a new 9AH dekka vrla
battery discharged at 6 amps (2 ohm resistance) I measure 56 minutes
to 11.00 volts or 5.6 AH.
For a 6+ year old but 5 years in service identical battery (420
flight hours) that has never been deep discharged or been on a
maintainer, I measure 52 minutes to 11.00 volts or 5.2 AH again at 6
amps discharge rate. All tests were done with the battery stabilized
at a 66*F basement room temperature for several days after top up
with a Schumaker 1162.
Interesting!
I don't have an easy way to compare the cranking capabilities other
than last winter the two paralleled batts in my Z-14 system seemed to
crank a bit slower than normal.
Hmmm . . . a pair of 9 a.h. batteries seems a bit light.
How even are you swapping them out?
It cranked fine all summer but I have just replaced the oldest
battery anyway. Hasn't been much colder than freezing yet to compare
this winter. I too am surprised that the old battery delivered 93% of
the capacity of the newer one at a 6 amp discharge rate.
I'll attempt to compare the current flow from each battery while
cranking (clamp on dc ammeter) the next time I fly. (I have the
automatic parallel option during cranking). Should give an indication
of how another 4 year in service batt compares to the new one for cranking.
The 'definitive' test is done with some adjustable
high current load, a timer and a voltmeter. Something
like:
http://aeroelectric.com/Pictures/Battery_Testers/HF91129_4.jpg
Our load measurements would not be comparable given the big
differences in battery sizes. But doing the load test on your
'new' and 'old' battery conducted in the same manner would yield
some useful data. Your observations for discharge under a
static load are interesting. Thanks for sharing!
I'll be talking to my long time friend and battery guru
in the next few weeks, I'll ask him about these observations.
Bob . . .
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| Subject: | Re: RG Batteries: I learned something last night |
A few years back, we had a dead short on the battery cable before the
contactor that drained the battery dead, dead, dead. I arrived and
removed the short after about 2 hours. The battery read ~ 5v at that
time. Charged it overnight and put it back in service. Several weeks
later I replaced it when it failed to start the engine, charged it and
did a CBA II capacity test on it at 4 amps. It delivered just under 24
ah - not bad for a severely abused 24 ah battery. I'm still using it as
a shop battery.
Pax,
Ed Holyoke
On 10/29/2011 8:25 AM, Robert L. Nuckolls, III wrote:
> <nuckolls.bob@aeroelectric.com>
>
> That bench test battery I featured in a posting
> a few days ago had not be cap-checked in several years.
> The thing is over ten years old and has yielded a
> great return on investment.
>
> I did a load test on this battery about a week ago.
> It dumped about 300A for 15 seconds at the 70F mark
> on the load meter. A value that is less than 1/2 the
> as-new capability.
>
> Just for grins, I pulled out the CBAII battery tester.
> The bench battery had been on a maintainer for a couple days.
>
> I did a 6A discharge test. The value I use as exemplary
> of most of my instrumentation experiments. The battery
> delivered 24+ a.h. of useful energy! Going to the
> factory data on this battery we see:
>
> http://www.aeroelectric.com/Pictures/Curves/33AH_12V_Capacity_vs_Load.gif
>
>
> The factory says a 6.6A load will deplete this battery
> in about 4 hours . . . or 24+ a.h.
>
> In years past, my teachers modeled the battery as a large
> array of cells connected in a series-parallel configuration
> with EACH cell offering some finite energy value combined
> with it's own source impedance. If you loose 1/2 the cell
> in the full-up array, energy drops by 1/2 but source impedance
> doubles.
>
> This experiment last night showed that while the source
> impedance for the battery had doubled (1/2 the cranking
> snort), the total energy available was still almost as-new!
> This means that the gazillion itty-bitty cell analogy is not
> quite accurate. Those cells can experience a rise in
> source impedance while still offering their original
> energy capability.
>
> This battery as-new will deliver 9V at over 800A for
> 15 seconds. This suggests a source impedance of
> (12-9)/800 = .004 ohms. It now produces about 300A
> so the new source impedance is (12-9)/300 = .010
> ohms.
>
> So while the impedance has doubled, the available
> energy at 6A loading has been barely affected . . . if
> at all. A rise from .004 to .010 ohms source impedance
> has little influence on a test load of (12/6)= 2 Ohms.
>
> This argues with any analogy that suggests a "dead"
> micro-cell in a battery becomes totally disconnected
> from the array. It suggests that individual cells
> can demonstrate an ability to store and regurgitate
> energy while experiencing an independent and unrelated
> rise in source impedance.
>
> This discovery suggests that it is possible for a
> battery to meet battery-only-ops requirements while
> demonstrating reduced cranking performance. This ol'
> dog is still learning . . . and my grey haired bench
> test battery is still in service.
>
>
> Bob . . .
>
>
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