Today's Message Index:
----------------------
1. 06:14 AM - Re: Shorted cell risk? (Robert L. Nuckolls, III)
2. 06:30 AM - Re: Re: Shorted cell risk? (Ken Ryan)
3. 06:48 AM - Re: Re: Shorted cell risk? (Tim Olson)
4. 07:35 AM - Re: How about Z102? (Robert L. Nuckolls, III)
5. 07:35 AM - Re: Brownout Booster? (David Carter)
6. 07:37 AM - What is an RG battery? (Paul Millner)
7. 07:42 AM - Re: Brownout Booster? (Robert L. Nuckolls, III)
8. 10:13 AM - Re: Brownout Booster? (user9253)
9. 12:45 PM - Re: Re: Shorted cell risk? (Robert L. Nuckolls, III)
10. 01:58 PM - Re: Re: Shorted cell risk? (Ken Ryan)
11. 02:37 PM - Re: Re: Shorted cell risk? (Jan de Jong)
12. 03:28 PM - Re: Re: Shorted cell risk? (C&K)
13. 04:19 PM - EarthX ETX680C support (Steve Stearns)
Message 1
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| Subject: | Re: Shorted cell risk? |
At 06:05 PM 6/10/2020, you wrote:
>
>Bob, if two batteries are connected in parallel and one of the batteries
>develops a shorted cell, will the good battery discharge into the bad battery?
>If yes, would the rate of discharge be significant enough to quickly reduce
>the good battery voltage to that of the bad battery?
>Thanks
>
>--------
>Joe Gores
A maintained battery doesn't get shorted cells.
This was true back in the days of flooded
batteries and especially true of RG devices
today.
'Shorting' requires motion . . . in the heyday
of flooded batteries, active material 'pasted'
into the cell grids was subject to degradation
with age/abuse. Chunks would fall out of the
plate and migrate into the wet space between
plates. Most of the stuff would fall to a
'sediment space' under the array of plates.
Plates were EXPECTED to shed chunks of expended
material so there was a 'basement' for storing
the dead stuff.
But a battery left in service past its prime
was subject to so much flaking of active
material that adjacent plates could become
electrically connected . . . i.e. 'shorted
cell'
An RG battery is a different breed of cat
all together. Separators between cells
is a pretty tough but thin, porous
plastic or fiber. The plates are compacted
with significant force before being
inserted into the battery case.
For 'motion' to occur in these devices,
requires severe degradation of the
cell's active materials. This happens
when the battery has been allowed to
self-destruct with age or when subjected
to sustained over charging. Then you
get swelling of the active material
and risk of separator compromise.
But even in extreme cases of AGM
battery abuse, shorted cells are not
a given. I've seen some pretty badly
'puffed up' AGM batteries that were essentially
destroyed but had presented no shorted
cells.
A battery removed from service in an aircraft
at the appointed time in its life cycle is not
going to exhibit effects of severe ageing or
abuse.
Bob . . .
Message 2
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| Subject: | Re: Shorted cell risk? |
What is an RG battery? Without trying to continue mudding the waters, I
would venture to say that most builders these days who are using an auto
conversion engine not only have a single, internally regulated alternator,
they are also probably running LiPo batteries. Does this apply to LiPo
batteries as well? All of the experimentals that I am personally familiar
(eight or ten) are now using LiPo batteries.
On Thu, Jun 11, 2020 at 5:20 AM Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> At 06:05 PM 6/10/2020, you wrote:
>
>
> Bob, if two batteries are connected in parallel and one of the batteries
> develops a shorted cell, will the good battery discharge into the bad
> battery?
> If yes, would the rate of discharge be significant enough to quickly reduce
> the good battery voltage to that of the bad battery?
> Thanks
>
> --------
> Joe Gores
>
>
> A maintained battery doesn't get shorted cells.
> This was true back in the days of flooded
> batteries and especially true of RG devices
> today.
>
> 'Shorting' requires motion . . . in the heyday
> of flooded batteries, active material 'pasted'
> into the cell grids was subject to degradation
> with age/abuse. Chunks would fall out of the
> plate and migrate into the wet space between
> plates. Most of the stuff would fall to a
> 'sediment space' under the array of plates.
> Plates were EXPECTED to shed chunks of expended
> material so there was a 'basement' for storing
> the dead stuff.
>
> But a battery left in service past its prime
> was subject to so much flaking of active
> material that adjacent plates could become
> electrically connected . . . i.e. 'shorted
> cell'
>
> An RG battery is a different breed of cat
> all together. Separators between cells
> is a pretty tough but thin, porous
> plastic or fiber. The plates are compacted
> with significant force before being
> inserted into the battery case.
>
> For 'motion' to occur in these devices,
> requires severe degradation of the
> cell's active materials. This happens
> when the battery has been allowed to
> self-destruct with age or when subjected
> to sustained over charging. Then you
> get swelling of the active material
> and risk of separator compromise.
>
> But even in extreme cases of AGM
> battery abuse, shorted cells are not
> a given. I've seen some pretty badly
> 'puffed up' AGM batteries that were essentially
> destroyed but had presented no shorted
> cells.
>
> A battery removed from service in an aircraft
> at the appointed time in its life cycle is not
> going to exhibit effects of severe ageing or
> abuse.
>
> Bob . . .
>
Message 3
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| Subject: | Re: Shorted cell risk? |
I wouldn't make that assumption to "most". There are plenty of people using
both AGM and LiPo batteries. I know many of both, and many of both types
of alternators as well. So blanket statements don't really apply, but I do
agree that it would be nice to see architecture that covers both types of
alternators.
Tim
On 6/11/2020 8:27 AM, Ken Ryan wrote:
> What is an RG battery? Without trying to continue mudding the waters,
> I would venture to say that most builders these days who are using an
> auto conversion engine not only have a single, internally regulated
> alternator, they are also probably running LiPo batteries. Does this
> apply to LiPo batteries as well? All of theexperimentals that I am
> personally familiar (eight or ten) are now using LiPo batteries.
>
> On Thu, Jun 11, 2020 at 5:20 AM Robert L. Nuckolls, III
> <nuckolls.bob@aeroelectric.com <mailto:nuckolls.bob@aeroelectric.com>>
> wrote:
>
> At 06:05 PM 6/10/2020, you wrote:
>> <fransew@gmail.com <mailto:fransew@gmail.com>>
>>
>> Bob, if two batteries are connected in parallel and one of the
>> batteries
>> develops a shorted cell, will the good battery discharge into the
>> bad battery?
>> If yes, would the rate of discharge be significant enough to
>> quickly reduce
>> the good battery voltage to that of the bad battery?
>> Thanks
>>
>> --------
>> Joe Gores
>
> A maintained battery doesn't get shorted cells.
> This was true back in the days of flooded
> batteries and especially true of RG devices
> today.
>
> 'Shorting' requires motion . . . in the heyday
> of flooded batteries, active material 'pasted'
> into the cell grids was subject to degradation
> with age/abuse. Chunks would fall out of the
> plate and migrate into the wet space between
> plates. Most of the stuff would fall to a
> 'sediment space' under the array of plates.
> Plates were EXPECTED to shed chunks of expended
> material so there was a 'basement' for storing
> the dead stuff.
>
> But a battery left in service past its prime
> was subject to so much flaking of active
> material that adjacent plates could become
> electrically connected . . . i.e. 'shorted
> cell'
>
> An RG battery is a different breed of cat
> all together. Separators between cells
> is a pretty tough but thin, porous
> plastic or fiber. The plates are compacted
> with significant force before being
> inserted into the battery case.
>
> For 'motion' to occur in these devices,
> requires severe degradation of the
> cell's active materials. This happens
> when the battery has been allowed to
> self-destruct with age or when subjected
> to sustained over charging. Then you
> get swelling of the active material
> and risk of separator compromise.
>
> But even in extreme cases of AGM
> battery abuse, shorted cells are not
> a given. I've seen some pretty badly
> 'puffed up' AGM batteries that were essentially
> destroyed but had presented no shorted
> cells.
>
> A battery removed from service in an aircraft
> at the appointed time in its life cycle is not
> going to exhibit effects of severe ageing or
> abuse.
>
> Bob . . .
>
Message 4
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| Subject: | Re: How about Z102? |
At 03:12 PM 6/10/2020, you wrote:
>Regarding proposed Z102 thanks for taking time
>to developing an architecture specific to auto
>conversion engines. One comment I have after
>reviewing is that from what I have seen, many
>(probably most?) auto conversions seem to use
>denso alternators with internal regulators. I
>think it may be relatively uncommon that these
>alternators are modified so that their
>regulators are moved to the external, or
>replaced with more conventional aircraft
>alternators. I therefore wonder if the
>architecture might be more useful if it also
>accounted for this idiosyncrasy=C2 of using a
>single internally regulated alternator?
>
>Ken
This has been an ongoing debate on these pages
decades. I've sorta taken the tack that we should
strive to publish and recommend the best we know
how to do as opposed to becoming an echo chamber
for concepts from other venues.
To be sure, reliability of COTS alternators
is very high . . . in fact, I've been told there
are STCs now for adapting COTS alternators
to TC aircraft sans ov protection. I've not
seen any such documents but it wouldn't surprise
me.
We'll have to leave adoption of such variants
up to the individual builder. For the foreseeable
future, I'll continue to strive for as much
failure tolerance as the technology and tools
at hand will offer.
Speaking of COTS alternators . . . Lister
Graeme Coates did an excellent piece on ND alternator
modifications published in Kitplanes last year.
You can see a copy of that article here:
https://tinyurl.com/yxmpw3on
. . . along with other writings on the same
subject.
Bob . . .
Message 5
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| Subject: | Re: Brownout Booster? |
Can someone please provide a link to a brownout booster that would be
suitable for the Z101 brownout bus? I'm having trouble finding one that
appears suitable, possibly because I don't really know what I should be
looking for.
Thanks,
David
--
David Carter
david@carter.net
On Wed, Jun 10, 2020 at 4:54 PM Charlie England <ceengland7@gmail.com>
wrote:
> On 6/10/2020 2:56 PM, David Carter wrote:
>
> Found this device on eBay, and wondering if it is suitable for use on the
> brownout bus on Z101?
>
>
> https://www.ebay.com/itm/WaterProof-DC-DC-12V-to-14V-10A-140W-STEP-UP-Power-Converter-Regulator-DC/391330544024?hash=item5b1d1e3998:g:0ssAAOSw7FRWVx3p
>
>
> There are very similar looking 12v-to-12v versions, but they are twice the
> price. Not sure why.
>
>
> ---
> David Carter
> david@carter.net
>
> Might work, but note that minimum input voltage is 10V (not uncommon for
> starting voltage to sag lower than that), and 'soft start' is a half
> second; might be too slow to prevent the brownout issue.
>
> Charlie
>
>
> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient&utm_term=icon> Virus-free.
> 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_-803626533076655720_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>
Message 6
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| Subject: | What is an RG battery? |
Recombinant Gas... designed to turn any liberated hydrogen/oxygen back into water,
to avoid electrolyte depletion.
Paul
Message 7
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| Subject: | Re: Brownout Booster? |
At 09:32 AM 6/11/2020, you wrote:
>Can someone please provide a link to a brownout
>booster that would be suitable for the Z101
>brownout bus? I'm having trouble finding one
>that appears suitable, possibly because I don't
>really know what I should=C2 be looking for.=C2
What are your brownout bus loads?
Bob . . .
Message 8
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| Subject: | Re: Brownout Booster? |
eBay item 222626498012 claims to work with as little as 3 volts input.
eBay item 224017421193 claims to work with as little as 8.5 volts input.
The descriptions are written in broken English. Example:
(please to ensure that output voltage above on input voltage)
You could experiment with more than one type until you find one that works.
A separate DC-DC booster could even be installed for each protected load.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=496777#496777
Message 9
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| Subject: | Re: Shorted cell risk? |
At 08:27 AM 6/11/2020, you wrote:
>What is an RG battery?
Sorry . . . recombinant gas (RG) also known as absorbed glass mat (AGM)
and valve regulated sealed lead acid (VRLA) and starved electrolyte
cells. Lots of ways to describe the same technology.
>Without trying to continue mudding the waters, I
>would venture to say that most
>builders these days who are using an auto conversion engine not only have a
>single, internally regulated alternator, they are also probably running
LiPo
>batteries.
Hmmm . . . 'most'?
> Does this apply to LiPo batteries as well? All of the=C2 experimentals
>that I am personally familiar (eight or ten) are now using LiPo batteries.
As to cell shorting . . . we're told that
lithium related fires are initiated by short
circuiting the cell. In the 787 batteries,
the shorts were internal. Given their energy
density, the aftermath of a cell-short is
almost guaranteed to be spectacular.
The LiPoFe technology seems most sensitive
to electrical abuse . . . a condition that
gave impetus to rather elaborate battery
management systems being folded into
'holy watered' products.
I've been playing with my new West Mountain Radio
battery analyzer. Did a constellation of deep
discharge tests on some 18650 cells. I'll take
a few of them down to zero . . . let them set
for a day or so and then see what happens to
their demonstrated capacity.
Bob . . .
Message 10
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| Subject: | Re: Shorted cell risk? |
>
>
> Hmmm . . . 'most'?
>
I can only speak to my experience. I am personally familiar with 5
SuperSTOLs, 1 Highlander, 2 Zeniths and 1 Rans. Every one has ditched lead
acid for LiPo. Of course these are all Light Sport Aircraft and weight is a
big concern when max gross is 1320. I would guess LiPo has not been as
widely adopted in larger aircraft with more weight to play with.
Ken
>
Message 11
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| Subject: | Re: Shorted cell risk? |
Dear all,
Better not confuse LiPo with LiFePO4 (also called LFP). Important
differences.
A search with both terms will lead to some clarity I expect.
Cheers,
Jan de Jong
Message 12
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| Subject: | Re: Shorted cell risk? |
Opposite experience for me with only one out of six familiar local
aircraft using Lithium. With the relatively economical older aircraft
in my neighborhood that I'm not familiar with I'd be very surprised if
even one out of 10 has converted.
Ken L
On 11/06/2020 4:43 PM, Ken Ryan wrote:
>
>
> Hmmm . . . 'most'?
>
>
> I can only speak to my experience. I am personally familiar with 5
> SuperSTOLs, 1 Highlander, 2 Zeniths and 1 Rans. Every one has ditched
> lead acid for LiPo. Of course these are all Light Sport Aircraft and
> weight is a big concern when max gross is 1320. I would guess LiPo has
> not been as widely adopted in larger aircraft with more weight to play
> with.
>
> Ken
>
Message 13
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| Subject: | EarthX ETX680C support |
Cross-post (with permission) from the Canard Aviators List:
3a.
*EarthX ETX680C support*
From: Tristan Vincent-Philpot
<tristanphilpot@hotmail.com?subject=Re:%20EarthX%20ETX680C%20support>
I flew the family from KVGT to KSNA yesterday, an uneventful trip except
that on 10nm approach into John Wayne, the battery fault indicator lit on
my instrument panel. The light was solid, not blinking, meaning that a
hardware problem had occurred and could not be reset. I prioritized flying
the airplane to a safe landing while I switched the Alternator off to avoid
trying to push more charge into the battery with an unknown fault.
Once the dust settled and I had parked and unloaded the family into the
air-conditioned comfort of the ACI Jet terminal, I set about
troubleshooting. I took the rear cabin panel off and checked the condition
of the battery itself. It was not hot, or smoking and there was no
indication of any damage of any kind. With the Master switch on I checked
the volts and amps and as expected the battery voltage had depleted
slightly but otherwise everything was normal except with the fault warning
light on.
I re-read the operator's manual for the EarthX and it was clear that there
was a hardware fault detected and the battery would need to be replaced.
I then called EarthX and was put through to technical support (=98Reg
=99) who
was very knowledgeable and said that the most likely cause they have seen
with this issue is that one of the dual redundant internal disconnectors
had thrown a fault and latched the warning. He said I should try and charge
it, and if as he suspected it accepted a charge normally, I should not
worry about flying it home as the cells have been operating perfectly
normally and take months to deviate from this practice. By lucky
coincidence I had purchased an Optimate TM-291 charger as recommended by
EarthX a couple of days ago and had it with me so borrowed a generator from
the FBO and plugged it in. The battery charged completely normally in about
20 mins to full charge, then held the charge, didn=99t get warm or an
ything
unusual. Throughout this process Reg was engaged, looking for possible
replacements in stock nearby, looking at my photos of the charger and other
indications. Once charged, we left the airplane while we went to explore
Laguna Beach (the reason for the flight) then returned in the late
afternoon. Sure enough the battery had held its charge as usual and the
engine started first time. I flew the 1.5 hours home to Las Vegas with
appropriate monitoring of the electrical system behavior with nothing amiss
except the warning light on. When I shut down at home base, the battery
volts indicated full ~13.4V as expected, and again the battery was cool
with no smoke or any other problems.
Today, I went online to EarthX website as directed by Reg and filled out
the online warranty form. He helped me find a couple of the parameters and
pre-warned the warranty department to expect my submission. Within minutes
I had an accepted warranty exchange and the replacement battery is shipping
to me now. When it arrives I can then remove the old one and return it.
Overall this has INCREASED my confidence in the Lithium battery system from
EarthX and I was very impressed with the attitude and knowledge of the
technical support on hand when I called. It could have been much worse.
As an aside, I asked if there was any chance they were working on a venting
system for the ETX680C model to provide added safety for cabin
installations. He said no, there=99s no room in that form factor, but
that it
would be possible for the regular size ETX680 (non-compact model). I told
him I thought it would encourage more in the experimental community to make
the leap to their batteries as the TSO=99d ETX900-TSO is eye-watering
ly more
expensive but is the only option with a vent kit. He agreed - I guess we
=99ll
have to wait and see what transpires
Also a shout out to ACI-Jet at KSNA, they were awesome all day, supplying a
comfortable lounge for the family with drinks and snacks, a generator and
cables, waiving the usual fees ($60) for a 10gal fuel purchase. I
thoroughly recommend them if you find yourself heading to Orange County.
Also the Optimate chargers are very nicely made and work well.
A long yearned for family day at the beach was not really impacted and we
all arrived safely home for dinner. And I learned stuff :-)
Tristan
N142LE
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