Today's Message Index:
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1. 10:15 AM - Re: Crowbar OV Module (Robert L. Nuckolls, III)
2. 12:09 PM - Lithium Ion Battery for OBAM aircraft project (Robert L. Nuckolls, III)
3. 02:19 PM - Re: Lithium Ion Battery for OBAM aircraft project (Sacha)
4. 03:57 PM - Re: Lithium Ion Battery for OBAM aircraft project (Robert L. Nuckolls, III)
5. 05:20 PM - Re: Crowbar OV Module (Robert L. Nuckolls, III)
Message 1
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| Subject: | Re: Crowbar OV Module |
At 02:06 AM 5/11/2013, you wrote:
>Good morning Bob,
>
>I just bought one crowbar OV module from your site. Could you tell
>me as precisely as possible the value of the voltage which triggers
>the module (14.5V ??)?
>
>I plan to use a Rotax 912UL with a Ducati voltage regulator and an
>Aliant Lithium battery (Ref X4 12V 9.2Ah). This battery is
>supposedly best charged at 14.4-14.6V, but they also say that
>voltage over 14.5V could damage the battery ...
>Of course I am trying to figure out if the crowbar OV module can
>protect this battery from voltage over 14.5V.
>
>Regards
>Eric Boutteloup
Sure. The Crowbar ov modules we produce are
set on the bench at 16.4 volts and they
have a significant negative temperature
coefficient. In very cold conditions, the
voltage will be a bit higher, when hot
they'll be a bit lower. This is consistent
with a lead acid battery's performance needs
with respect to ambient temperature.
The OV module is NOT intended nor designed
to guard the welfare of a battery although
it's presence in the system will benefit
the battery and all other electro-whizzies
from a runaway alternator.
The failure condition we're concerned
with is a failed regulator that allows
an alternator to run essentially full bore.
While not a spectacular event with your Rotax
18A alternator, it's another matter with a
60A belt driven alternator on a Lycoming.
The Crowbar OVM is a rational addition to
your system but it's not going to catch
a poorly performing regulator that's putting
your battery at risk for LONG term effects
of inappropriate voltage setting.
Care and feeding of your lithium battery is
another matter entirely. I'd not heard of
the Aliant brand until your enquiry. Poking
around on the 'net I find that they've made
what appears to be a good penetration of the
sport vehicles markets. They filed for a trademark
ALIANT
late last year. http://tinyurl.com/d2ohsjo
I'm reading also where a part of their organization
has been awarded a contract to do safety
studies for the US Army to explore characteristics
based on environments and maintenance issues.
This is how the B787 cells should have been
tested too. Not unlike the work that the Navy's
battery labs in Crane, IN used to do and
may still do.
The lithium elephants in the room are: (1) Can
one drop an Li battery into location previously
occupied by lead-acid or Ni-Cad (with no other
changes to the system) and expect (2) a service life
commensurate with increased costs,(3) performance
enhancements commensurate with less weight and (3)
reliability equal too or better than the batteries
being replaced (i.e. pre-mature chemistry death
and catching fire is very much frowned upon!).
The technology is relatively young and variations
on a theme for chemistries increases the numbers
of variables for the sifting of elephants.
I quick appraisal of Internet images for Aliant
batteries
http://tinyurl.com/bnfnfeq
failed to show a battery with a socket for a "genius
charger" nor did I see any batteries fitted with
ports to connect such chargers. All the recommended
chargers ranging from wall warts (including Battery
Tenders) . . .
[]
[]
to 'Super chargers' . . . .
[]
. . . appear to make two-wire connections to the battery.
This means that the charger cannot perform to any
cell-by-cell charging protocols. Now, are they 'tailored'
to lithium chemistry? Don't know. It would be interesting
to plot the output from one of these 'recommended' chargers
to see if they exhibit any more smarts than the commercial
off the shelf chargers for lead-acid.
So, Eric my friend, the SHORT answer to your question is
that the OV module has no duties or practical expectations
for enhancing battery performance on your airplane. Where
did you read about 14.5v charge levels being detrimental
to the product? Many vehicular alternator regulators may
produce system voltages at or maybe above 14.5 volts. Only
an accurate voltmeter on YOUR airplane will tell this
tale.
My suspicion is that the literature is referring to long
term maintenance or 'float' voltages. A system
operating voltage that was suited to your SVLA battery
may be no more detrimental to the Li-Ion given the
intermittent and short term application of the "excess"
voltage. SLVA is the same way. You MAINTAIN it at just
a tad above 13.0 volts and CHARGE it at 14.2 to 14.8 volts.
The numbers for a drop-in lithium battery should be just
FINE with similar CHARGE voltages . . . the MAINTENANCE
voltage will no doubt be different. This graph taken from
a learned treatise on Li batteries
Emacs!
Suggests a room temperature open circuit voltage
on the order of 3.35 volts per cell or 13.4 volts
for an array of 4 cells. This means that the
Li-battery 'maintainer' needs to be on the order
of 13.5 volts . . . probably not too high for a
lead-acid battery either.
Given the drop-in-SVLA-replacement marketing policy
for the Aliant Li-products, you need not concern
yourself for any duties of ownership beyond having
a voltmeter in your airplane that confirms a 14.2
to 14.8 flight ops voltage . . . and a ov protection
system for mitigating regulator failures.
Bob . . .
Message 2
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| Subject: | Lithium Ion Battery for OBAM aircraft project |
At 01:02 PM 5/11/2013, eric.boutteloup@laposte.net wrote:
Good morning Bob,
Thank you very much for your quick, documented and very interesting answer.
1) I found, the information about voltage over
14.5V on the link below (from ULM Technology a
french dealer for ultra light airplane parts)
http://commerce.ciel.com/ulmtechnologie/Article/60193-X4_this.aspx?
The sentence (in french !!) at the bottom :
=9DAttention en cas de surtension sup=C3=A9rieure
=C3 14.5V, la batterie se d=C3=A9t=C3=A9rior=C3=A9e, dans ce
cas, la garantie ne s'applique pas=9D
Which means : Warning, in case of overvoltage
above 14.5V, the battery become damaged, in this case, warranty will not
apply.
2) I just have had a look to the Aliant website and they say :
Charging voltage
14.4 V
Maximum charging voltage
14.6 V
They also claim that :
This family of batteries is indicated for the
replacement of all types of lead batteries
currently in use without making any changes to
the electrical system in the vehicle. Refer to
the online configurator to choose the suitable model.
3) I am in the process of building a micro light
Aircraft from a kit, a Nynja from Bestoff. So I
cannot check yet the voltage of the Ducati
regulator. On the 912UL2 installation manual,
regarding the regulator (which is supposedly a
Ducati one...) , it says: usefull voltage : 14 +/-0.3V (from 1000+/-250 rpm)
In consequence it seams quite probable that this
low weight battery can survive in my future
912UL2 electric environment, provided that the
regulator do not over volt too long and too often above 14.6V.
I agree. Since I responded to your query, I've
discovered that the Aliant products utilize
A123 cylindrical cells. A123 filed for bankruptcy
protection last fall
http://tinyurl.com/cmy4xnj
and seems to have received an influx of cash
from a Chinese firm. I believe A123 was the
supplier of cells to Cessna's Li battery program
which has been put on the back burners pending
recovery from a battery fire in a Citation on
the ramp last year.
I believe the Cessna battery used prismatic
cells . . . 'rectangular bricks' as opposed to
the cylindrical 'jelly roll' cells which seem
to be less prone to the separator failures suspected
of being root cause for the failures.
Aha! Just ran across this statement from a document
found at:
http://tinyurl.com/c4hetul
ALIANT compared currently with SSB
Powersport/Haijue/Skyrich/Ballistic/Motocell/Shorai (Chinese cells)
1) Up to 16 Models are required to stock. Aliant
has only 6 different models to manage covering
over 95% of motorcycle applications.
2) Aliant product is made with A123 System
cells-that means maximum safety and performance.
The oldest and industry leading cell producer
from the USA. Involved in Lithium technology since Space Shuttle.
3) S kyrich, (SSB, Haijue) use Lithium Polymer
cells not lithim iron phosphate technology-there
are differences in terms of quality and safety as
well as they can explode and catch fire when overvoltage and short circuit.
It does not happen with A123 System cell as they
meet the UL1342 testing. Published
on<http://www.birdman.net.au> www.Birdman.net.au website.
I was unable to find any such testing protocol on
the UL website at http://tinyurl.com/brpeblz
Further, a stroking of the search engines failed
to take notice of "UL1342" anywhere except on the
birdman website. I'll write to them for clarification.
Maybe this is a typo.
I did find a listing for UL2575, the only one that
speaks to lithium batteries (for power tools).
4) ALIANT have integrated BMS that allows the system to get fully charged
with:
* Motorcycle electric system without any change
and can handle system failure with absolute safety.
* A list of compatible chargers (Battery tender,
Optimate Lithium, CTEK X800 and 3600)
These features are not possible with other brands
as there is no BMS inside, and you need to use a
dedicated charger to charge the battery and make
sure its ok. ALIANT extends battery life becuase
it ALWAYS WORKS, both in charge and discharge,
and maintains the cells at same voltages, balancing along the series of
cells.
It seems the Aliant products are fitted with a battery
management system that takes care of housekeeping chores
unique to lithium batteries. That's a different ball
game. Even the little $3 Li-Ion batteries for my grandson's
helicopter is fitted with a BMS.
Emacs!
Internal management of lithium battery vagaries
would go a LONG way toward making the product user
friendly and a drop-in-replacement for legacy
batteries.
This explains the images I posted earlier suggesting
that my plain-vanilla battery tenders are suited to
service on Aliant products. The cylindrical cells
may also go to improved separator performance.
It does give pause to consider the admonition for
a "14.5 volt limit" on charging voltage. An internal
battery management system should be able to accommodate
ANY charging voltage not wildly departed from that found
in legacy lead-acid systems.
In any case, what I've learned about Aliant today
suggests that it stands above other popular products
in terms of BMS for operational issues and cylindrical
cells for failure issues. The claim for UL approval
to the wrong spec is curious . . . I'll explore further.
I've not yet discovered any US suppliers of Aliant
batteries but I've run out of time to look more today.
Bob . . .
Message 3
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| Subject: | Lithium Ion Battery for OBAM aircraft project |
It does not happen with A123 System cell as they meet the UL1342 testing.
Published on www.Birdman.net.au <http://www.birdman.net.au> website.
I was unable to find any such testing protocol on
the UL website at http://tinyurl.com/brpeblz
Further, a stroking of the search engines failed
to take notice of "UL1342" anywhere except on the
birdman website. I'll write to them for clarification.
Maybe this is a typo.
I did find a listing for UL2575, the only one that
speaks to lithium batteries (for power tools).
I believe that they mean UL1642.
http://ulstandardsinfonet.ul.com/scopes/scopes.asp?fn=1642.html
Message 4
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| Subject: | Lithium Ion Battery for OBAM aircraft project |
>
>I believe that they mean UL1642.
>
><http://ulstandardsinfonet.ul.com/scopes/scopes.asp?fn=1642.html>http://ulstandardsinfonet.ul.com/scopes/scopes.asp?fn=1642.html
>
Could be. Thanks. I'll see if I can track down
either one . . .
Bob . . .
Message 5
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| Subject: | Re: Crowbar OV Module |
Care and feeding of your lithium battery is
another matter entirely. I'd not heard of
the Aliant brand until your enquiry. Poking
around on the 'net I find that they've made
what appears to be a good penetration of the
sport vehicles markets. They filed for a trademark
ALIANT
late last year. http://tinyurl.com/d2ohsjo
I'm reading also where a part of their organization
has been awarded a contract to do safety
studies for the US Army to explore characteristics
based on environments and maintenance issues.
SCRATCH THE ABOVE.
Seems there's a company called Alliant/Valence that makes
a lot of aerospace/military hardware. These are the
folks getting the testing job . . . NOT Aliant
Bob . . .
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