Today's Message Index:
----------------------
1. 06:43 AM - Re: IS a COM ANTENNA GROUND PLANE NECESSARY (user9253)
2. 07:12 AM - Re: Valid test for voltage regulator (Ernest Christley)
3. 08:17 AM - Re: Re: IS a COM ANTENNA GROUND PLANE NECESSARY (Robert L. Nuckolls, III)
4. 08:36 AM - Re: Re: Revmaster engine with EarthX battery (Robert L. Nuckolls, III)
5. 09:20 AM - ETX36D Charge/Discharge studies at 13.0 to 15.0 Volts (Robert L. Nuckolls, III)
6. 09:50 AM - Re: IS a COM ANTENNA GROUND PLANE NECESSARY (user9253)
7. 10:08 AM - Re: Re: Revmaster engine with EarthX battery (Ken Ryan)
8. 10:08 AM - Re: Re: IS a COM ANTENNA GROUND PLANE NECESSARY (Robert L. Nuckolls, III)
9. 10:14 AM - Re: Valid test for voltage regulator (Robert L. Nuckolls, III)
10. 02:04 PM - Re: Re: RV10 primary elec sys wiring (Robert L. Nuckolls, III)
11. 02:35 PM - Re: Re: RV10 primary elec sys wiring (Robert L. Nuckolls, III)
Message 1
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| Subject: | Re: IS a COM ANTENNA GROUND PLANE NECESSARY |
One would think that the Kitfox steel tube fuselage frame would make a
good ground plane, but it does not. With the antenna mounted to a flat
plate that is welded to the top of the fuselage, the SWR was 2.4 or worse.
I then connected a 22 inch long wire to one of the antenna mounting screws and
extended it horizontally and forward over the open baggage area. Surprise!
The SWR greatly improved. Below are the numbers. My friend might
experiment by adding additional ground plane radials.
.
FREQ _ SWR
118 _ 2.30
119 _ 1.78
120 _ 1.49
121 _ 1.24
122 _ 1.20
123 _ 1.30
124 _ 1.35
125 _ 1.39
126 _ 1.59
127 _ 1.82
128 _ 1.95
129 _ 1.99
130 _ 2.00
131 _ 1.99
132 _ 2.00
133 _ 2.10
134 _ 2.20
135 _ 2.50
136 _ 3.10
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=497673#497673
Message 2
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| Subject: | Re: Valid test for voltage regulator |
I'm the one with the "Scorpion" battery.=C2- No BMS.Well, I may be overs
tating the case.=C2- It does look like it has a network of connections to
balance the cells.=C2- But there is no facility to remove the input volt
age.=C2-
I'll rig up a way to mount the generator in the lathe this evening, and put
the regulator in a more realistic test.
Charlie, I ohmed the leads out, and none of them seem to be tied directly t
o ground.
On Tuesday, August 11, 2020, 6:48:31 PM EDT, Robert L. Nuckolls, III <n
uckolls.bob@aeroelectric.com> wrote:
At 03:09 PM 8/11/2020, you wrote:
I got a regulator off of Amazonthat matches the generator I'm adding. Wante
d to test its exact set pointto make sure I don't kill another LiFePObatter
y.
=C2- What brand/model of battery?
I connected anadjustable power supply to the two-prong input, and tracked t
he voltagebetween the single output lead and the aluminum case as I cranked
up thesupply.=C2- The output tracked the input all the way up and past t
he14.7V advertised regulation point.=C2- At 20.5V, the limit of mysupplie
s capability, there was 19.8V between the output lead and theregulator case
.=C2- I added a light as a small load, and got the sameresults.
Would I embarrass myself for leaving a review that this is a regulatorthat
doesn't regulate?=C2- Granted, the input expects an AC voltage,and I'm gi
ving it DC, but shouldn't it still regulate the output tosomething close to
the nominal voltage?
=C2- The RECTIFIER/regulator is an AC driven
=C2- device. It turns ON by triggering a silicon
=C2- controlled rectifier which STAYS on until
=C2- the AC wave form passes through zero volts
=C2- at the end of the half-cycle.
=C2- It's unlikely that you're going to 'kill'
=C2- a battery with a in-situ test of this
=C2- regulator. It may prove to regulate
=C2- a bit higher or lower than optimum . . .
=C2- but if your battery features a BMS,
=C2- then 'optimum' is about a barn-door
=C2- wide.
=C2- Bob . . .
Message 3
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| Subject: | Re: IS a COM ANTENNA GROUND PLANE NECESSARY |
>Surprise! The SWR greatly improved.
Yup!
>Below are the numbers. My friend might
>experiment by adding additional ground plane radials.
Probably won't change much . . .
>
>.
>FREQ _ SWR
>118 _ 2.30
>119 _ 1.78
>120 _ 1.49
>121 _ 1.24
>122 _ 1.20
>123 _ 1.30
>124 _ 1.35
>125 _ 1.39
>126 _ 1.59
>127 _ 1.82
>128 _ 1.95
>129 _ 1.99
>130 _ 2.00
>131 _ 1.99
>132 _ 2.00
>133 _ 2.10
>134 _ 2.20
>135 _ 2.50
>136 _ 3.10
The feedpoint impedance of an un-compensated
1/4 wave vertical is on the order of 30 ohms
at resonance . . . so the BEST expected SWR
over the range of interest would be about what
you're seeing 1.20:1
We see that SWR minimizes at 122, not quite in
the center of the range of interest. If this
antenna can be 'trimmed', try shortening it
1/4" at a time until SWR minimizes at 127Mhz.
Then I suspect you'll be under 3:1 over full
range . . . a useful antenna.
118 to 136 is a pretty BIG bandwidth . . .
about 14% . . . those numbers are not all
that bad! I'd go with it as-is or if
you're feeling ambitious, trim it a bit.
Good work!
Bob . . .
Message 4
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| Subject: | Re: Revmaster engine with EarthX battery |
At 09:05 AM 8/11/2020, you wrote:
>OK. It seems like my "understanding" of battery charging is
>seriously flawed. I thought, for example, that if a partially
>discharged battery was connected to a higher voltage source, the
>battery would be charged to that voltage level. Since the EarthX has
>a charged, resting voltage of 13.2 - 13.3 volts I thought that if it
>was connected to a 13.5 volt source, it would eventually charge the
>battery. Apparently, none of this is true?
As long as you DON'T put silicon 'smarts' between the
energy source and the battery to be charged.
Those plots I published for stepped increases in
charging voltage on a single LiFePO4 cell speaks
to the phenomenon you've cited. This is generally
true for all the SVLA, Flooded and Gel versions
of the Lead-Acid technology . . . because our
vehicular DC power systems EVOLVED around the
charge/discharge reactions of lead, sulphur, oxygen
and hydrogen. This convention is 160+ years old.
It also works for the new kids on the block that
use lithium, iron, phosphorous and oxygen but with
a big 'gotcha' . . . the differences in voltage
for these two chemistries keep them from being
form/fit/function interchangeable.
Our alternators, regulators, light bulbs, legacy
electronics, etc. etc. were optimized for function
in a 14.2-14.4 volt world that was ESTABLISHED
by the chemistry of the battery-of-choice for
over a century.
But three LiFePO4 cells stacked gives us a charge
(bus voltage) of 12.6V and a discharge (alternator-out)
voltage of about 11.1V. Decidedly incompatible with
the legacy lead-acid world.
Okay, cells stacked gives us a bus voltage of 16.8 and a
14.8V alternator-out voltage. Again . . . not a drop-in
replacement.
Some folks have decided to offer 4-stack batteries
with no 'smarts' and which will be charged to
3.6 volts per layer . . . a potential that does
not charge the chemistry to its latent capabilities . . .
but 'good enough' if the target users are willing
to accept compromised performance in exchange for weight
savings.
Further, it turns out that this very energetic
chemistry comes with some risks. It will produce
extra-ordinary fault currents for it's size.
Prolonged deep discharge can seriously injure
an otherwise good battery. Charging at greater
than legacy lead-acid voltages will indeed
'stuff' more energy into the battery but allowing
or recommending operations above the legacy
levels poses system wide risks that may be
hazardous to hardware. The batteries are at
greater risk for catastrophic failure to
to over-charging or hard-charging.
So, BMS enter stage-right:
A judicious collection of transistors and things
can be hammered into a 'battery management system'
that will pound our square cornered lithium
product into a round, lead-acid hole.
Hence, products like EarthX and AeroVoltz
with BMS system will FUNCTION in the lead-
acid hole with minimized risks but performance
compromises.
'Barefoot' lithium products will also
function in the lead-acid world but safeguards
offered by BMS fitted products are the
user's responsibility.
Bob . . .
Message 5
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| Subject: | ETX36D Charge/Discharge studies at 13.0 to 15.0 Volts |
Okay, just finished the series of plots on the
ETX36D battery that EarthX donated to the cause
a few years back.
Did a series of charges at 13.0 to 15.0 volts with
constant current power supply. Note in the charge
plots, the voltage climbs slowly as the battery
charges but takes an upward 'jump' as the battery
achieves full charge and the BMS unhooks the battery
terminating the charge. Voltage rises to the power
supply's set point.
Note that ALL plots from 13.5 to 15.0 push enough
energy into the battery for the BMS to say "halt".
The 13.0 plot produces no such effect.
The discharge plots are similarly interesting.
Note that no matter what voltage of 13.5 or
greater, the battery acquires the same amount
of energy.
At 13.0V, energy imparted is about 1.8 AH,
a small fraction of the otherwise 11 AH full
charge.
From this experiment I deduce that the battery's
BMS considers 13.5 / 4 = 3.35 volts per cell to
be the full-charge target.
I further observed that the when connecting
the discharged battery to a 13.0 volt, 5A
supply . . . the initial charge current rose
to 5 amps! It just didn't stay there very
long. I need to get a multi-channel DAS
up and running so we can see voltage and
currents plotted together.
Nonetheless, I think it reasonable to assert
that fiddling with the voltage regulator on
the Revmaster engine with some hopes of
mitigating damage to a demonstrably FRAGILE
PM alternator is not useful. I have
further thoughts on that issue for a later
post.
Further, these experiments show that for
batteries fitted with an agile BMS, raising
the bus voltage will NOT offer the user
greater access to any un-exploited potential
for chemical energy storage.
Finally, fiddling with the voltage regulator
when substituting a BMS fitted battery into
an SVLA's system is of no benefit. The voltage
regulator can continue to supply ship's needs
while the battery takes care of itself.
I just received some new, A123 cells that I'll
survey for any variation in what we've seen
with the consumer product cells tested so far.
Bob . . .
Message 6
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| Subject: | Re: IS a COM ANTENNA GROUND PLANE NECESSARY |
Thanks for replying Bob. The antenna is a beautiful Rami antenna. I am sure
my friend does NOT want to cut it. He might experiment with additional
ground plane wires, but otherwise leave it as is, not perfect but good enough.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=497682#497682
Message 7
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| Subject: | Re: Revmaster engine with EarthX battery |
Thanks Bob. That does help clear things up.
On Wed, Aug 12, 2020 at 7:42 AM Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> At 09:05 AM 8/11/2020, you wrote:
>
> OK. It seems like my "understanding" of battery charging is seriously
> flawed. I thought, for example, that if a partially discharged battery was
> connected to a higher voltage source, the battery would be charged to that
> voltage level. Since the EarthX has a charged, resting voltage of 13.2 -
> 13.3 volts I thought that if it was connected to a 13.5 volt source, it
> would eventually charge the battery. Apparently, none of this is true?
>
>
> As long as you DON'T put silicon 'smarts' between the
> energy source and the battery to be charged.
>
> Those plots I published for stepped increases in
> charging voltage on a single LiFePO4 cell speaks
> to the phenomenon you've cited. This is generally
> true for all the SVLA, Flooded and Gel versions
> of the Lead-Acid technology . . . because our
> vehicular DC power systems EVOLVED around the
> charge/discharge reactions of lead, sulphur, oxygen
> and hydrogen. This convention is 160+ years old.
>
> It also works for the new kids on the block that
> use lithium, iron, phosphorous and oxygen but with
> a big 'gotcha' . . . the differences in voltage
> for these two chemistries keep them from being
> form/fit/function interchangeable.
>
> Our alternators, regulators, light bulbs, legacy
> electronics, etc. etc. were optimized for function
> in a 14.2-14.4 volt world that was ESTABLISHED
> by the chemistry of the battery-of-choice for
> over a century.
>
> But three LiFePO4 cells stacked gives us a charge
> (bus voltage) of 12.6V and a discharge (alternator-out)
> voltage of about 11.1V. Decidedly incompatible with
> the legacy lead-acid world.
>
> Okay, cells stacked gives us a bus voltage of 16.8 and a
> 14.8V alternator-out voltage. Again . . . not a drop-in
> replacement.
>
> Some folks have decided to offer 4-stack batteries
> with no 'smarts' and which will be charged to
> 3.6 volts per layer . . . a potential that does
> not charge the chemistry to its latent capabilities . . .
> but 'good enough' if the target users are willing
> to accept compromised performance in exchange for weight
> savings.
>
> Further, it turns out that this very energetic
> chemistry comes with some risks. It will produce
> extra-ordinary fault currents for it's size.
> Prolonged deep discharge can seriously injure
> an otherwise good battery. Charging at greater
> than legacy lead-acid voltages will indeed
> 'stuff' more energy into the battery but allowing
> or recommending operations above the legacy
> levels poses system wide risks that may be
> hazardous to hardware. The batteries are at
> greater risk for catastrophic failure to
> to over-charging or hard-charging.
>
> So, BMS enter stage-right:
>
> A judicious collection of transistors and things
> can be hammered into a 'battery management system'
> that will pound our square cornered lithium
> product into a round, lead-acid hole.
>
> Hence, products like EarthX and AeroVoltz
> with BMS system will FUNCTION in the lead-
> acid hole with minimized risks but performance
> compromises.
>
> 'Barefoot' lithium products will also
> function in the lead-acid world but safeguards
> offered by BMS fitted products are the
> user's responsibility.
>
> Bob . . .
>
Message 8
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| Subject: | Re: IS a COM ANTENNA GROUND PLANE NECESSARY |
At 11:45 AM 8/12/2020, you wrote:
>
>Thanks for replying Bob. The antenna is a beautiful Rami antenna. I am sure
>my friend does NOT want to cut it. He might experiment with additional
>ground plane wires,
Useful experiment . . . pls share observations
> but otherwise leave it as is, not perfect but good enough.
Right on . . .
Bob . . .
Message 9
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| Subject: | Re: Valid test for voltage regulator |
At 09:09 AM 8/12/2020, you wrote:
>I'm the one with the "Scorpion" battery. No BMS.
>Well, I may be overstating the case. It does look like it has a network of
>connections to balance the cells. But there is no facility to
>remove the input voltage.
That comports with other bare-foot lithium
offers I've seen. They bring out taps between
the stacks of cells to allow installation
of either (a) and external balance network
or (2) lithium specific battery chartger that
includes a balancing feature.
>
>
>I'll rig up a way to mount the generator in the lathe this evening,
>and put the regulator in a more realistic test.
Sounds like a plan.
Photo-document your setup and share results!
Bob . . .
Message 10
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| Subject: | Re: RV10 primary elec sys wiring |
Alex,
You need to move this conversation to the AeroElectric-List.
I see that you are presently subscribed.
What kind of engine and ignition system? (your excel spread sheet didn't
come through).
Your task is not difficult but there are a lot of questions
about hardware and manner in which the airplane will be
used.
I don't have the time to do consulting on individual projects
except when the subject matter sorts out details of physics
and practice of interest to the List as a whole.
But there's a bunch of folk on the List with more experience
than I in the fabrication and operation of owner built and
maintained airplanes who would be glad to join and help
move your project along.
This doesn't mean that I won't participate but with
all the irons I have in the fire, I need to tailor
my activities to those where I can help the most.
Tell us more about your project.
Bob . . .
At 01:49 PM 8/12/2020, you wrote:
>Dear Bob,=C2
>
>I am frustrated, feeling like I know nothing.
>The more I read - the more this feeling is inside=C2 me.=C2
>Commercial aviation=C2 experience=C2 now can't help (
>
>I have made load analyses, as you advised
>(attached excel doc) - could you, please, give
>the direction on the primary electrical system?=C2
>still thinking on how to integrate a small
>backup battery (what equipment=C2 should it power,
>as EFIS displays and standby display have their
>own backup batteries), how many buses to use and
>determine what equipment must be powered from exact bus...
>attached=C2 list has ELA, sources list and
>equipment list. ELA will be triple-checked, for sure -=C2
>it was not an easy task to determine load in
>different=C2 phases without experience, but
>exciting and, I believe, everything=C2 will be fine!=C2
>
>My main goal is to create a simple, but
>redundant and reliable system based on hardware
>which friend=C2 has already purchased=C2
>(frustrated regarding alternator=C2 with built-in
>voltage regulator- as read before in the Book it
>is not the best option, but will see ...)=C2 =C2
>=C2
>Could you, please, be so kind to help...?
>
>Kindest regards,
>Alex
Message 11
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| Subject: | Re: RV10 primary elec sys wiring |
At 04:03 PM 8/12/2020, you wrote:
>Bob,=C2
>
>thanks a lot for advice - i will create topic.=C2
>Great thanks for support!=C2
Alex,
Like I said . . . too many irons in the fire . . . it
slipped my mind that we'd already opened a List topic
and I published a suggested starting point for your
architecture:
See https://tinyurl.com/y6ku7lbh
List your ideas as to which accessories would
power from each bus in this drawing?
Bob . . .
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