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user9253
Joined: 28 Mar 2008
Posts: 1921
Location: Riley TWP Michigan
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nuckolls.bob(at)aeroelect
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 Posted: Tue Oct 07, 2014 2:16 pm Post subject: Lithium Battery Article in Kitplanes |
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At 22:17 2014-10-06, you wrote:
| Quote: |
There is an article by Dean Sigler in the November 2014 issue of
KitPlanes Magazine discussing lithium batteries. There is a picture
of lithium batteries being charged inside of a fireplace. Should
aircraft lithium battery boxes be made of firebrick? 
|
Just got home from the little trip to Canada. Delightful time
but didn't get to do the kayak trip. Too cold. Quite
memorable for a host of other reasons.
I've done some preliminary charge/discharge experiments
and I've 'discovered' some interesting things which for
the moment I'll have to catalog as anecdotal because I
did not rigorously control test conditions or record
data. While sitting on airplanes (lots of them!) over the
past week, I've designed a test plan that requires some
fabrication and programming.
If my preliminary discoveries don't fall to closer
scrutiny, I'll have some interesting 'meat' to include
in my next installment of the lithium saga.
I tried to get the KP article but the website is
not responding at the moment. Will try again later.
Bob . . .
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nuckolls.bob(at)aeroelect
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| Posted: Thu Oct 09, 2014 5:49 am Post subject: Lithium Battery Article in Kitplanes |
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At 22:17 2014-10-06, you wrote:
| Quote: | --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com>
There is an article by Dean Sigler in the November 2014 issue of KitPlanes Magazine discussing lithium batteries. There is a picture of lithium batteries being charged inside of a fireplace. Should aircraft lithium battery boxes be made of firebrick? |
Had a great vacation trip punctuated by broken
airplanes and overnight stays in travel at both
ends . . . what are the odds?
Got a look at the article cited. This is pretty
much an academic assemblage of published facts
about the various lithium products being studied
and tried in MOTIVE POWER applications where
energy density and charge/discharge protocols are
much more demanding. The article is probably
accurate but minimally relevant to what we're
doing . . . or proposing to do with lithium battery
products.
Getting a lithium battery to burn is like any
other catastrophic energy release in that it
takes a combination of stacked conditions. In
the case of an ENGINE CRANKING / STANDBY POWER
battery, the first condition we'll strive to
minimize is the choice of chemistries.
My preliminary findings working with the 26650
liFe cells purchased off eBay suggest that their
ratings, and coincidentally their in-service
risks for abuse, are strongly influenced by the
boundaries on charge/recharge limits. Many articles
I've read suggest that optimum battery life is
achieved if the cells are cycled between about
80 and 20 percent of their chemical energy limits.
The hybrid vehicles program their battery management
systems to keep routine cycling of the cell packs
within these or similar limits thus accepting
a designed-in de-rating of battery capacity.
This de-rating along with choice of a chemistry
with the most robust resistance to conflagration
suggest that fire-brick battery boxes are probably
overkill. Lowered risks for LiFe fire not-withstanding,
the lithium products finding their way onto TC
aircraft ARE being housed in enclosures that
ASSUME a potential for the worst . . . said
enclosures are designed to contain a battery
fire and vent products of combustion overboard.
Know too that these offerings have a significant
proportion of procurement expense tied up in the
battery management system electronics!
[img]cid:.0[/img]
http://tinyurl.com/l6xbev7
As of this date, I'me aware of no similar
prophylactics against catastrophic failure being
offered to the OBAM aviation community.
My cursory studies of the lithium question have produced
some enlightenment and mild surprises . . . but the
data gathering methodology was too coarse . . . it seems
that differences as small as 0.1 volts per cell in charging
voltage can have a large effect on energy stored. I've
go more cells ordered and I'm assembling better data
gathering tools.
One thing I can offer at this stage of the study is
to strongly object to any marketing of a lithium product
with words that speak to "lead-acid equivalency" . . .
these are an entirely different breed of cat and to
suggest that an end user can expect performance and
maintenance issues to be a matter of drop-in equivalency
is at best disingenuous and at worst a tad fraudulent.
To the snow-mobiler or biker who's interests are largely
limited to engine cranking and service life, the loose
application of words like 'equivalency' is not terribly
egregious. Airplanes are be VERY different in operational
expectations, system integration and failure modes management.
In the mean time, know that the article cited in the
subject line of this tread has little significance to
the issues we're wrestling with here on the List.
Watch this space . . .
Bob . . .
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ralphmariafinch(at)gmail.
Guest
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| Posted: Thu Oct 09, 2014 6:50 am Post subject: Lithium Battery Article in Kitplanes |
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I'm a bit puzzled as to why we, the E/AB community, would seriously consider Lithium batteries for the main battery. To save weight or space? The savings are insignificant and the unknowns and risks are not insignificant. Lithium chemistry makes sense for highly portable electronics (laptops, tablets, phones) but not so much for us.
Sure, we DO build and fly *experimental* aircraft, but there's a limit to how much experimenting most will do. The more proven non-flooded Lead-based batteries are very safe and convenient and I use them on both my certificated Aircoupe and the RV-9A that will hopefully be flying next year.
Ralph Finch
On Thu, Oct 9, 2014 at 6:48 AM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
| Quote: | At 22:17 2014-10-06, you wrote:
| Quote: | --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>
There is an article by Dean Sigler in the November 2014 issue of KitPlanes Magazine discussing lithium batteries. There is a picture of lithium batteries being charged inside of a fireplace. Should aircraft lithium battery boxes be made of firebrick? |
Had a great vacation trip punctuated by broken
airplanes and overnight stays in travel at both
ends . . . what are the odds?
Got a look at the article cited. This is pretty
much an academic assemblage of published facts
about the various lithium products being studied
and tried in MOTIVE POWER applications where
energy density and charge/discharge protocols are
much more demanding. The article is probably
accurate but minimally relevant to what we're
doing . . . or proposing to do with lithium battery
products.
Getting a lithium battery to burn is like any
other catastrophic energy release in that it
takes a combination of stacked conditions. In
the case of an ENGINE CRANKING / STANDBY POWER
battery, the first condition we'll strive to
minimize is the choice of chemistries.
My preliminary findings working with the 26650
liFe cells purchased off eBay suggest that their
ratings, and coincidentally their in-service
risks for abuse, are strongly influenced by the
boundaries on charge/recharge limits. Many articles
I've read suggest that optimum battery life is
achieved if the cells are cycled between about
80 and 20 percent of their chemical energy limits.
The hybrid vehicles program their battery management
systems to keep routine cycling of the cell packs
within these or similar limits thus accepting
a designed-in de-rating of battery capacity.
This de-rating along with choice of a chemistry
with the most robust resistance to conflagration
suggest that fire-brick battery boxes are probably
overkill. Lowered risks for LiFe fire not-withstanding,
the lithium products finding their way onto TC
aircraft ARE being housed in enclosures that
ASSUME a potential for the worst . . . said
enclosures are designed to contain a battery
fire and vent products of combustion overboard.
Know too that these offerings have a significant
proportion of procurement expense tied up in the
battery management system electronics!
[img]cid:.0[/img]
http://tinyurl.com/l6xbev7
As of this date, I'me aware of no similar
prophylactics against catastrophic failure being
offered to the OBAM aviation community.
My cursory studies of the lithium question have produced
some enlightenment and mild surprises . . . but the
data gathering methodology was too coarse . . . it seems
that differences as small as 0.1 volts per cell in charging
voltage can have a large effect on energy stored. I've
go more cells ordered and I'm assembling better data
gathering tools.
One thing I can offer at this stage of the study is
to strongly object to any marketing of a lithium product
with words that speak to "lead-acid equivalency" . . .
these are an entirely different breed of cat and to
suggest that an end user can expect performance and
maintenance issues to be a matter of drop-in equivalency
is at best disingenuous and at worst a tad fraudulent.
To the snow-mobiler or biker who's interests are largely
limited to engine cranking and service life, the loose
application of words like 'equivalency' is not terribly
egregious. Airplanes are be VERY different in operational
expectations, system integration and failure modes management.
In the mean time, know that the article cited in the
subject line of this tread has little significance to
the issues we're wrestling with here on the List.
Watch this space . . .
Bob . . .
|
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
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nuckolls.bob(at)aeroelect
Guest
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| Posted: Thu Oct 09, 2014 7:05 am Post subject: Lithium Battery Article in Kitplanes |
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|
At 09:48 2014-10-09, you wrote:
| Quote: | I'm a bit puzzled as to why we, the E/AB community, would seriously
consider Lithium batteries for the main battery. To save weight or
space? The savings are insignificant and the unknowns and risks are
not insignificant. Lithium chemistry makes sense for highly portable
electronics (laptops, tablets, phones) but not so much for us.
Sure, we DO build and fly *experimental* aircraft, but there's a
limit to how much experimenting most will do. The more proven
non-flooded Lead-based batteries are very safe and convenient and I
use them on both my certificated Aircoupe and the RV-9A that will
hopefully be flying next year.
|
A lucid deliberation my friend . . . based on my
own experience and personal design goals for seeking the
'elegant solution', I have no foundation for a contrary
argument.
But until we know as much as can be discovered
about these critters, arguments proposing any
design goal will be on shaky foundation.
Bob . . .
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
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kenryan
Joined: 20 Oct 2009
Posts: 426
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| Posted: Thu Oct 09, 2014 7:41 am Post subject: Lithium Battery Article in Kitplanes |
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I am comfortable using Lithium batteries based on the many, many thousands that are currently in use in snowmachines, motorcycles, etc., and the many that are currently being used in EAB aircraft.
On Thu, Oct 9, 2014 at 6:48 AM, Ralph Finch <ralphmariafinch(at)gmail.com (ralphmariafinch(at)gmail.com)> wrote:
| Quote: | I'm a bit puzzled as to why we, the E/AB community, would seriously consider Lithium batteries for the main battery. To save weight or space? The savings are insignificant and the unknowns and risks are not insignificant. Lithium chemistry makes sense for highly portable electronics (laptops, tablets, phones) but not so much for us.
Sure, we DO build and fly *experimental* aircraft, but there's a limit to how much experimenting most will do. The more proven non-flooded Lead-based batteries are very safe and convenient and I use them on both my certificated Aircoupe and the RV-9A that will hopefully be flying next year.
Ralph Finch
On Thu, Oct 9, 2014 at 6:48 AM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
| Quote: | At 22:17 2014-10-06, you wrote:
| Quote: | --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>
There is an article by Dean Sigler in the November 2014 issue of KitPlanes Magazine discussing lithium batteries. There is a picture of lithium batteries being charged inside of a fireplace. Should aircraft lithium battery boxes be made of firebrick?  |
  Had a great vacation trip punctuated by broken
  airplanes and overnight stays in travel at both
  ends . . . what are the odds?
  Got a look at the article cited. This is pretty
  much an academic assemblage of published facts
  about the various lithium products being studied
  and tried in MOTIVE POWER applications where
  energy density and charge/discharge protocols are
  much more demanding. The article is probably
  accurate but minimally relevant to what we're
  doing . . . or proposing to do with lithium battery
  products.
  Getting a lithium battery to burn is like any
  other catastrophic energy release in that it
  takes a combination of stacked conditions. In
  the case of an ENGINE CRANKING / STANDBY POWER
  battery, the first condition we'll strive to
  minimize is the choice of chemistries.
  My preliminary findings working with the 26650
  liFe cells purchased off eBay suggest that their
  ratings, and coincidentally their in-service
  risks for abuse, are strongly influenced by the
  boundaries on charge/recharge limits. Many articles
  I've read suggest that optimum battery life is
  achieved if the cells are cycled between about
  80 and 20 percent of their chemical energy limits.
  The hybrid vehicles program their battery management
  systems to keep routine cycling of the cell packs
  within these or similar limits thus accepting
  a designed-in de-rating of battery capacity.
  This de-rating along with choice of a chemistry
  with the most robust resistance to conflagration
  suggest that fire-brick battery boxes are probably
  overkill. Lowered risks for LiFe fire not-withstanding,
  the lithium products finding their way onto TC
  aircraft ARE being housed in enclosures that
  ASSUME a potential for the worst . . . said
  enclosures are designed to contain a battery
  fire and vent products of combustion overboard.
  Know too that these offerings have a significant
  proportion of procurement expense tied up in the
  battery management system electronics!
 Â
[img]cid:.0[/img]
http://tinyurl.com/l6xbev7
  As of this date, I'me aware of no similar
  prophylactics against catastrophic failure being
  offered to the OBAM aviation community.
  My cursory studies of the lithium question have produced
  some enlightenment and mild surprises . . . but the
  data gathering methodology was too coarse . . . it seems
  that differences as small as 0.1 volts per cell in charging
  voltage can have a large effect on energy stored. I've
  go more cells ordered and I'm assembling better data
  gathering tools.
  One thing I can offer at this stage of the study is
  to strongly object to any marketing of a lithium product
  with words that speak to "lead-acid equivalency" . . .
  these are an entirely different breed of cat and to
  suggest that an end user can expect performance and
  maintenance issues to be a matter of drop-in equivalency
  is at best disingenuous and at worst a tad fraudulent.
  To the snow-mobiler or biker who's interests are largely
  limited to engine cranking and service life, the loose
  application of words like 'equivalency' is not terribly
  egregious. Airplanes are be VERY different in operational
  expectations, system integration and failure modes management.
  In the mean time, know that the article cited in the
  subject line of this tread has little significance to
  the issues we're wrestling with here on the List.
  Watch this space . . .
   Â
 Bob . . .
|
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| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
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