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jim(at)poogiebearranch.co
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 Posted: Mon Dec 19, 2011 11:03 am Post subject: Lithium-Ion Battery? |
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"923te" wrote:
<< Probably by the time you get an STC the new Lithium ion batteries
will be available for our grummans. You might want to consider that
before investing a lot of time into a battery that will probably fade
away in the not to distant future. The lithuim ion battery will be half
the weight of the current battery. Maybe even less.>>
I was intrigued, because I've been following some of the "electric
flying" stuff at EAA and other sites, and there's a lot of "control
stuff" that goes along with those batteries. Got me wondering what
Concorde knew that others didn't... So I went to their website to read:
<<"The lithium-ion main aircraft battery will not be a retrofit battery.
In order to assure safe operation, the lithium-ion battery must be
integrated into the control software and electronics of the aircraft
system. Redundant safety systems built into the aircraft as well as into
the battery are required to control the lithium-ion battery. With
adequate protection systems and monitoring, the battery will provide
reliable power for the aircraft of the future.>>
<<Advantages:
* High energy density potential for yet higher capacities.
* Does not need prolonged priming when new. One regular charge is all
that's needed.
* Relatively low self-discharge - self-discharge is less than half that
of nickel-based batteries.
* Low Maintenance - no periodic discharge is needed; there is no memory.
* Specialty cells can provide very high current.>>
<<Limitations:
* Requires protection circuit to maintain voltage and current within
safe limits. Protection circuitry involves both additional hardware and
software.
* On aircraft battery monitoring and alarms will be required for safe
operation.
* Subject to aging, even if not in use - storage in a cool place at 40%
charge reduces the aging effect.
* Transportation restrictions - shipment of larger batteries may be
subject to regulatory control.
* Expensive to manufacture - about 40 percent higher in cost than
nickel-cadmium.
* Not a fully mature chemistry - metals and chemicals are changing on a
continuing basis.
* Extremely flammable electrolyte. ">>
While the advantages sound great, the disadvantages are significant, and
it sounds like there's a lot of work to be done before it will be
available for "new designs" - likely a LOT longer for retrofit -
especially since they are saying "The lithium-ion main aircraft battery
will not be a retrofit battery."
Seems like we'd be safe going ahead with a Concorde for the next 2-3
years, at least... (Just my 2 cents worth.)
Jim Parker (hoping to be a "new" Cheetah owner before the end of the
year...)
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Discover
Joined: 26 Feb 2007
Posts: 429
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| Posted: Mon Dec 19, 2011 12:02 pm Post subject: Lithium-Ion Battery? |
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Jim
I think there is perhaps a lot of protection language on the Concorde website. That is liability protection. The experimental world is already using the Lithium Iron Phosphate batteries as direct replacements. These latest generation batteries, like in the Chevy Volt and others do not have the issues of blowing up etc and don't require the controls you are talking about
See. http://www.lithiummoto.com/
And others like for more info
Where you can replace your 29lb 12volt battery with one that weighs around 2.5lbs as in the following picture
http://www.lithiummoto.com/gallery.html
Ned
Sent from my iPhone
On Dec 19, 2011, at 1:00 PM, <jim(at)poogiebearranch.com> wrote:
| Quote: |
"923te" wrote:
<< Probably by the time you get an STC the new Lithium ion batteries
will be available for our grummans. You might want to consider that
before investing a lot of time into a battery that will probably fade
away in the not to distant future. The lithuim ion battery will be half
the weight of the current battery. Maybe even less.>>
I was intrigued, because I've been following some of the "electric
flying" stuff at EAA and other sites, and there's a lot of "control
stuff" that goes along with those batteries. Got me wondering what
Concorde knew that others didn't... So I went to their website to read:
<<"The lithium-ion main aircraft battery will not be a retrofit battery.
In order to assure safe operation, the lithium-ion battery must be
integrated into the control software and electronics of the aircraft
system. Redundant safety systems built into the aircraft as well as into
the battery are required to control the lithium-ion battery. With
adequate protection systems and monitoring, the battery will provide
reliable power for the aircraft of the future.>>
<<Advantages:
* High energy density potential for yet higher capacities.
* Does not need prolonged priming when new. One regular charge is all
that's needed.
* Relatively low self-discharge - self-discharge is less than half that
of nickel-based batteries.
* Low Maintenance - no periodic discharge is needed; there is no memory.
* Specialty cells can provide very high current.>>
<<Limitations:
* Requires protection circuit to maintain voltage and current within
safe limits. Protection circuitry involves both additional hardware and
software.
* On aircraft battery monitoring and alarms will be required for safe
operation.
* Subject to aging, even if not in use - storage in a cool place at 40%
charge reduces the aging effect.
* Transportation restrictions - shipment of larger batteries may be
subject to regulatory control.
* Expensive to manufacture - about 40 percent higher in cost than
nickel-cadmium.
* Not a fully mature chemistry - metals and chemicals are changing on a
continuing basis.
* Extremely flammable electrolyte. ">>
While the advantages sound great, the disadvantages are significant, and
it sounds like there's a lot of work to be done before it will be
available for "new designs" - likely a LOT longer for retrofit -
especially since they are saying "The lithium-ion main aircraft battery
will not be a retrofit battery."
Seems like we'd be safe going ahead with a Concorde for the next 2-3
years, at least... (Just my 2 cents worth.)
Jim Parker (hoping to be a "new" Cheetah owner before the end of the
year...)
|
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jim(at)poogiebearranch.co
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| Posted: Tue Dec 20, 2011 6:57 pm Post subject: Lithium-Ion Battery? |
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Hey, Ned. It sounds really great, and I look forward to the day they
make the LIon battery avaialble for certified airplane use. My point
was really not so much about "is it safe" as it was about how long
before the feds will approve it for use in certified airplanes. Then,
once that is done, how long (if ever) before Concorde elects to pursue
"retrofit" applications - which directly correlates to whether or not
the complex charging/discharging management circuits are required.
Slightly tangential to this topic, there was a great explanation of the
micro-controllers than handle all of this on the Apple website (of all
places) the Apple website, when the current-generation "aluminum shell"
MacBook Pros were launched. Basically, they showed how they were able
to take each cell of the battery, and install a small micro-controller
in the circuitry that permitted each cell's charge/discharge rate to be
managed independenty. This advance (not really original in concept to
Apple - it's been around in solar-cell technologies for home use for a
while) allowed them to get a pretty phenomenal battery life from these
laptops. I'm sure Concorde is (or will be) using something similar, as
most of the Radio-Controlled crowd is already on board with this as
well.
It's pretty amazing the pace of advancements in the battery field that
has occurred since fuel costs have come up to the present levels. I
hope that we eventually do see the availability of "practical" electric
flight while I'm still young enough to participate in it... There are
several electric airplanes flying now with about a 1-hour flight time,
and folks who follow that industry closely expect to see 2 to 2 1/2 hour
ranges within the next couple of years. That won't replace our internal
combustion engines for cross-country flying, but for a 1-2 hour local
area sightseeing flight, or just going out to shoot some touch-and-go
patterns, it would sure be less expensive!
Great to be alive and a pilot these days, even with the high cost of -
well - EVERYTHING!
Jim (Expecting "my" Cheetah to be ready any day now... Worse than a kid
on Christmas Eve!)
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