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lgold(at)quantum-associat
Guest

Posted: Fri Oct 07, 2011 10:47 am Post subject: Electric aircraft issues

Bob, or anyone else out there in Aeroelectric land with Li-Ion battery knowledge,

I have started to build, what I hope will be, an electric aircraft. The kit, a Cumulus motor glider, with a 20:1 glide ratio is ideal, and I have non-explosive A123 batteries. The 560 batteries, 25HP/100V electric motor, and controller should weigh in about the same as and fly as long as it would with the prescribed Rotax engine. With a potential to fly about 2000 cycles (read 2000 flights), these batteries will cost about 20% of the cost of mogas… if I can figure out how to configure the batteries and charge them properly.

I could use a lot of advice regarding the battery pack architecture, charging, and maintaining these Li-Ion batteries. I need to know how to weld or solder the batteries into packs (I am thinking 32 packs places in series; each pack having 16 or 17 cells in parallel). I need to find an inexpensive way to charge them (I am thinking I could charge the 8 packs at a time; 30V (at) 50A for up to 45 minutes) but need to understand more about charging and balancing.

A123 won’t give me the time of day since they changed their focus to sell batteries only to auto manufacturers so any words of wisdom would be helpful.

Thanks,

Les  

  [quote][b]

nuckolls.bob(at)aeroelect
Guest

Posted: Fri Oct 07, 2011 12:39 pm Post subject: Electric aircraft issues

At 01:43 PM 10/7/2011, you wrote:



Bob, or anyone else out there in Aeroelectric 

land with Li-Ion battery knowledge,

I have started to build, what I hope will be, an 

electric aircraft. The kit, a Cumulus motor 

glider, with a 20:1 glide ratio is ideal, and I 

have non-explosive A123 batteries. The 560 

batteries, 25HP/100V electric motor, and 

controller should weigh in about the same as and 

fly as long as it would with the prescribed Rotax 

engine. With a potential to fly about 2000 cycles 

(read 2000 flights), these batteries will cost 

about 20% of the cost of mogas… if I can figure 

out how to configure the batteries and charge them properly.



I could use a lot of advice regarding the battery 

pack architecture, charging, and maintaining 

these Li-Ion batteries. I need to know how to 

weld or solder the batteries into packs (I am 

thinking 32 packs places in series; each pack 

having 16 or 17 cells in parallel). I need to 

find an inexpensive way to charge them (I am 

thinking I could charge the 8 packs at a time; 

30V (at) 50A for up to 45 minutes) but need to 

understand more about charging and balancing.



A123 won’t give me the time of day since they 

changed their focus to sell batteries only to 

auto manufacturers so any words of wisdom would be helpful.

Thanks,

Les



   I wish that the bright light at the end of

   the tunnel was not an oncoming train.



   There has been an intense interest in lighter/

   more energetic batteries for aircraft since

   Cessna bolted batteries and generators to the

   C-140 many moons ago.



   There have been some fits and starts on lithium

   devices with mixed results. There ARE lithium

   products flying on a number of air transport

   category aircraft. Until a short time ago,

   Cessna had sold several Citations with lithium

   starting batteries aboard. Cessna had invested

   mucho bux in a development program that for all

   intents and purposes, produced an airworthy

   product. Then we have these two documents:

SL525C-24-02A-R01

SB525C-24-05

  The background on these publications seems to

  stand on a battery fire in a factory airplane

  that caused extensive damage and was difficult

  to control.



  It seems that the battery monitoring system may

  have failed to predict and warn against a 'normal'

  recharge of a badly depleted battery. Hence an

  field investigation into software issues. The

  other document speaks to what's necessary to replace

  a lithium battery with either lead-acid or ni-cad

  with only a logbook entry. This document does

  not speak to a Cessna program that proposes to replace

  all lithium products from the field.



  I'm not ready to recommend that anyone bolt

  a lithium device to their airplane. When the

  big guys are stubbing their toes in spectacular

  ways, I think it unwise to think that we are

  well advised to expand a technology (that

  is still an experiment) into our fun machines.



  By the way, I think the cells involved in the

  battery fire were the Lithium Iron devices from

  A123. The fat lady hasn't even been handed the

  sheet music much less received a curtain call.

  I'll continue to track this series of events.



  It sound like you'd like to be involved in the

  development of a next generation aircraft. There

  are a number of good texts on battery management.

  I'll see if I can get some titles and sources

  for you.

   Bob . . .

handainc(at)madisoncounty
Guest

Posted: Fri Oct 07, 2011 1:08 pm Post subject: Electric aircraft issues

I'd be interested in information about building battery packs and 

welding or soldering those batteries into battery packs. I just bought a 

Li-on pack for my CPAP machine - $359! I'd love to try building my own 

battery pack for a couple of purposes if I can do so safely and gain 

some education.



M. Haught

On 10/7/2011 3:34 PM, Robert L. Nuckolls, III wrote:

 	  Quote: 	
		   

 <nuckolls.bob(at)aeroelectric.com>

 At 01:43 PM 10/7/2011, you wrote:



 Bob, or anyone else out there in Aeroelectric land with Li-Ion battery 

 knowledge,

 I have started to build, what I hope will be, an electric aircraft. 

 The kit, a Cumulus motor glider, with a 20:1 glide ratio is ideal, and 

 I have non-explosive A123 batteries. The 560 batteries, 25HP/100V 

 electric motor, and controller should weigh in about the same as and 

 fly as long as it would with the prescribed Rotax engine. With a 

 potential to fly about 2000 cycles (read 2000 flights), these 

 batteries will cost about 20% of the cost of mogas… if I can figure 

 out how to configure the batteries and charge them properly.



 I could use a lot of advice regarding the battery pack architecture, 

 charging, and maintaining these Li-Ion batteries. I need to know how 

 to weld or solder the batteries into packs (I am thinking 32 packs 

 places in series; each pack having 16 or 17 cells in parallel). I need 

 to find an inexpensive way to charge them (I am thinking I could 

 charge the 8 packs at a time; 30V (at) 50A for up to 45 minutes) but need 

 to understand more about charging and balancing.



 A123 won’t give me the time of day since they changed their focus to 

 sell batteries only to auto manufacturers so any words of wisdom would 

 be helpful.

 Thanks,

 Les



 I wish that the bright light at the end of

 the tunnel was not an oncoming train.



 There has been an intense interest in lighter/

 more energetic batteries for aircraft since

 Cessna bolted batteries and generators to the

 C-140 many moons ago.



 There have been some fits and starts on lithium

 devices with mixed results. There ARE lithium

 products flying on a number of air transport

 category aircraft. Until a short time ago,

 Cessna had sold several Citations with lithium

 starting batteries aboard. Cessna had invested

 mucho bux in a development program that for all

 intents and purposes, produced an airworthy

 product. Then we have these two documents:

 SL525C-24-02A-R01

 SB525C-24-05

 The background on these publications seems to

 stand on a battery fire in a factory airplane

 that caused extensive damage and was difficult

 to control.



 It seems that the battery monitoring system may

 have failed to predict and warn against a 'normal'

 recharge of a badly depleted battery. Hence an

 field investigation into software issues. The

 other document speaks to what's necessary to replace

 a lithium battery with either lead-acid or ni-cad

 with only a logbook entry. This document does

 not speak to a Cessna program that proposes to replace

 all lithium products from the field.



 I'm not ready to recommend that anyone bolt

 a lithium device to their airplane. When the

 big guys are stubbing their toes in spectacular

 ways, I think it unwise to think that we are

 well advised to expand a technology (that

 is still an experiment) into our fun machines.



 By the way, I think the cells involved in the

 battery fire were the Lithium Iron devices from

 A123. The fat lady hasn't even been handed the

 sheet music much less received a curtain call.

 I'll continue to track this series of events.



 It sound like you'd like to be involved in the

 development of a next generation aircraft. There

 are a number of good texts on battery management.

 I'll see if I can get some titles and sources

 for you.

 Bob . . .


	




-- 

H.Marvin Haught Jr.

Haught&  Associates, Inc

Huntsville, AR 72740

Mauledriver(at)nc.rr.com
Guest

Posted: Fri Oct 07, 2011 1:41 pm Post subject: Electric aircraft issues

I'm thinking that getting to the team is working on Monnett's Waiex     project would be where some of the most current and directly applied     knowledge could be found.  

     

     Bill

     

     On 10/7/2011 2:43 PM, Les Goldner wrote:     [quote]                       <![endif]-->   <![endif]-->                

Bob, or           anyone else out there in Aeroelectric land with Li-Ion battery           knowledge,         

I have started to build, what I hope             will be, an electric aircraft. The kit, a Cumulus               motor glider, with a 20:1 glide ratio is ideal, and I             have non-explosive A123               batteries. The 560 batteries, 25HP/100V electric             motor, and controller should weigh in about the same as and             fly as long as it would with the prescribed Rotax engine.             With a potential to fly about 2000 cycles (read 2000             flights), these batteries will cost about 20% of the cost of             mogas… if I can figure out how to configure the batteries             and charge them properly.         

I could use a lot of advice regarding             the battery pack architecture, charging, and maintaining             these Li-Ion batteries. I need to know how to weld or solder             the batteries into packs (I am thinking 32 packs places in             series; each pack having 16 or 17 cells in parallel). I need             to find an inexpensive way to charge them (I am thinking I             could charge the 8 packs at a time; 30V (at) 50A for up to 45             minutes) but need to understand more about charging and             balancing.         

A123 won’t give me the time of day since             they changed their focus to sell batteries only to auto             manufacturers so any words of wisdom would be helpful.         

Thanks,

             Les         

        	  Quote: 	
		  

	
     [b]

sportav8r(at)gmail.com
Guest

Posted: Fri Oct 07, 2011 3:09 pm Post subject: Electric aircraft issues

There's a vendor on HFPack who is pretty knowledgable about the A123's as he sells them to hams interested in pedestrian mobile operations - not that he knows anything about aircraft, but he probably has the typical ham operator's willingness to help a fellow experimenter all he can - a lot like Bob N, here  



Google it.

-Bill B



On Fri, Oct 7, 2011 at 5:38 PM, Bill Watson <Mauledriver(at)nc.rr.com (Mauledriver(at)nc.rr.com)> wrote:

 [quote]                   I'm thinking that getting to the team is working on Monnett's Waiex     project would be where some of the most current and directly applied     knowledge could be found.  

     

     Bill

     

     On 10/7/2011 2:43 PM, Les Goldner wrote:      	  Quote: 	
		                                       

Bob, or           anyone else out there in Aeroelectric land with Li-Ion battery           knowledge,         

I have started to build, what I hope             will be, an electric aircraft. The kit, a Cumulus               motor glider, with a 20:1 glide ratio is ideal, and I             have non-explosive A123               batteries. The 560 batteries, 25HP/100V electric             motor, and controller should weigh in about the same as and             fly as long as it would with the prescribed Rotax engine.             With a potential to fly about 2000 cycles (read 2000             flights), these batteries will cost about 20% of the cost of             mogas… if I can figure out how to configure the batteries             and charge them properly.         

I could use a lot of advice regarding             the battery pack architecture, charging, and maintaining             these Li-Ion batteries. I need to know how to weld or solder             the batteries into packs (I am thinking 32 packs places in             series; each pack having 16 or 17 cells in parallel). I need             to find an inexpensive way to charge them (I am thinking I             could charge the 8 packs at a time; 30V (at) 50A for up to 45             minutes) but need to understand more about charging and             balancing.         

A123 won’t give me the time of day since             they changed their focus to sell batteries only to auto             manufacturers so any words of wisdom would be helpful.         

Thanks,

             Les         

        	  Quote: 	
		  

	
     



ist" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List

tp://forums.matronics.com

_blank">http://www.matronics.com/contribution



	


[b]

nuckolls.bob(at)aeroelect
Guest

Posted: Sat Oct 08, 2011 6:57 am Post subject: Electric aircraft issues

<snip>



 	  Quote: 	
		     Cessna had invested

   mucho bux in a development program that for all

   intents and purposes, produced an airworthy

   product. Then we have these two documents:

SL525C-24-02A-R01

SB525C-24-05


	


    I note that my cut-n-paste of these two citations

    did not carry the http: links with them. I'm

    away from the office but will re-post the

    links to these to documents when I get back.



    It may well be that there's a bright future for

    lithium technology in airplanes. Here's a

    supplier of off the shelf devices that has

    developed quite a following in the recreational

    vehicle and motorcycle markets.



http://www.shoraipower.com/



    Their batteries are fitted with special

    connectors that service a specialized

    charger/cell-balancing accessory. While

    not 'required' . . . it's very existence

    suggests that these batteries are not

    drop-in replacements for lead-acid.



http://www.shoraipower.com/downloads/shoraiLfxInstallGuide.pdf



    But as we all know and personally feel,

    the worst thing you can experience in

    flight is smoke/fire. Cessna thought they

    had cracked that nut. Both Cessna and

    the FAA were ready to allow these batteries

    aboard John Q Public's airplane.



    Obviously, there are some issues yet to be

    resolved so that probability for a repeat

    incident in flight drops to that magic

    one-event-per-billion flight hours that the

    FAA is so fond of.



    The "oncoming train" remark was inappropriate

    . . .  energy exploitation has evolved from

    basking in the sun to burning wood, burning

    pig fat/whale oil and upward to splitting

    atoms. Each step offered more concentrated

    and energetic releases of heat. Each step

    also came with elevated risks.



    No doubt risk mitigation for the lithium

    technologies will eventually prove adequate.



    Bob . . .

aerobubba(at)earthlink.ne
Guest

Posted: Sun Oct 09, 2011 6:12 am Post subject: Electric aircraft issues

Right off the top of my head, I can think of 3 freighter losses linked to Li batteries.  One got on the ground and burned on the runway for about 4 hours, without loss of life.  The other two didn't end so well.  In all cases, the batteries were palletized for shipping, not even part of an active circuit.  You can also google a video of a laptop sitting on the floor at LAX, and watch it erupt.  It's pretty spectacular.



FWIW, at least one of the planes in my past was configured with the NiCads outside the primary structure.  Absolute worst case, a runaway battery could exit the bottom of the composite blister without doing more grievous harm.  I don't think it would have even depressurized the plane.



Something to consider-



Glen Matejcek

nuckolls.bob(at)aeroelect
Guest

Posted: Sun Oct 09, 2011 6:59 am Post subject: Electric aircraft issues

 	  Quote: 	
		  



FWIW, at least one of the planes in my past was configured with the 

NiCads outside the primary structure.  Absolute worst case, a 

runaway battery could exit the bottom of the composite blister 

without doing more grievous harm.  I don't think it would have even 

depressurized the plane.


	


    Which speaks to the evolution of a technology . . .

    I recall working a MU2 accident down in TX that

    involved a ni-cad battery fire . . . that would

    have been in the 70's. We eventually learned how

    to live amicably with that technology's worst

    traits. Unfortunately, some of the lessons came

    with very high costs.



    I've not done a detailed study of incidents but

    I sense a trend suggesting that the lithium

    cells are particularly vulnerable to mischief when

    allowed to deeply discharge and are then recharged

    with the systems normal power source that is also

    capable of running the whole system.



    The Shorai folks caution against an energetic

    recharge of a deeply depleted battery. The task

    of bringing up a dead battery is best accomplished

    by their proprietary charger/cell-balancing product.



    I wonder if the laptop fire at LAX wasn't produced

    in a computer being recharged by a pax during a

    stop between planes. Batteries on airplanes tend

    to be deeply discharged more often than not . . .

    and then the pax hopes to get 'er charged back

    up between flights.



    So it seems likely that if one chooses to use

    the Shorai (or any other product) for an

    airplane, it is most likely to perform as advertised

    for a cranking battery where the alternator picks

    up system loads and replenishes a few percent of

    discharge each flight cycle.



    If one DOES experience an alternator failure,

    then by all means, use what ever energy the battery

    contains in carrying out plan-B. Upon reaching the

    ground, remove the battery from the airplane for

    specialized recharging in a less-risky environment.

    The Cessna ramp fire probably involved a disorderly

    recharge of a badly depleted battery.



   Bob . . .

Jim Berry

Joined: 10 Jan 2006
Posts: 237
Location: Denver

Posted: Sun Oct 09, 2011 9:24 am Post subject: Re: Electric aircraft issues

Bill Dube, who used to post to this site re his LED lights, probably has as much experience as anyone with the A123 batteries. He uses them in his battery powered dragster motorcycle (www.killacycle.com) and Bonneville racer. Search the archives for his take on using & charging these batts.



Jim Berry

RV-10

rparigoris

Joined: 24 Nov 2009
Posts: 797

Posted: Sun Oct 09, 2011 12:36 pm Post subject: Re: Electric aircraft issues

Hi Bob



You mentioned:

"The Shorai folks caution against an energetic

recharge of a deeply depleted battery."

This is not only true of a Lithium battery, but charging a discharged lead acid battery with a high powered alternator that's trying to maintain a constant voltage (just got aeroplane or car running from a jump start) is not very easy on the battery.

How could one limit the charging amps going into the battery yet still allow the alternator to carry any loads?

Ron P.

ceengland(at)bellsouth.ne
Guest

Posted: Sun Oct 09, 2011 2:06 pm Post subject: Electric aircraft issues

On 10/09/2011 03:36 PM, rparigoris wrote:

 	  Quote: 	
		   



 Hi Bob



 You mentioned:

 "The Shorai folks caution against an energetic

 recharge of a deeply depleted battery."

 This is not only true of a Lithium battery, but charging a discharged lead acid battery with a high powered alternator that's trying to maintain a constant voltage (just got aeroplane or car running from a jump start) is not very easy on the battery.

 How could one limit the charging amps going into the battery yet still allow the alternator to carry any loads?

 Ron P.



That was my 1st reaction, as well. Achieving it should be as simple (not 
	


to be confused with cheap...) as the alternator feeding a switching 

power supply which feeds only the custom charging circuit for the battery.



Charlie

aerobubba(at)earthlink.ne
Guest

Posted: Mon Oct 10, 2011 4:02 am Post subject: Electric aircraft issues

Hi Bob-



 	  Quote: 	
		     I recall working a MU2 accident down in TX that

    involved a ni-cad battery fire . . . 


	


was that the one involving a runaway battery that severed the pitch control system?



Do Not archive



Glen Matejcek

shenglu

Joined: 10 Oct 2011
Posts: 3

Posted: Tue Oct 11, 2011 6:54 pm Post subject: Re: Electric aircraft issues

I can think of three ships with lithium loss. One is on the ground, there is no loss of life, burnt down the runway about 4 hours. The other two did not end so well.

_________________
Gadgets | Flash Memory

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Oct 12, 2011 8:00 am Post subject: Electric aircraft issues

At 09:54 PM 10/11/2011, you wrote:

 	  Quote: 	
		  



I can think of three ships with lithium loss. One is on the ground, 

there is no loss of life, burnt down the runway about 4 hours. The 

other two did not end so well.


	


    Do you know of any Internet stories that describe

    these events?



    Also, welcome to the AeroElectric-List. Where

    are you located? Are you building an airplane?

   Bob . . .

nuckolls.bob(at)aeroelect
Guest

Posted: Fri Oct 14, 2011 6:50 pm Post subject: Electric aircraft issues

Posted: Mon Oct 10, 2011 4:02 am



 

 Bob:



 I recall working a MU2 accident down in TX that 

 involved a ni-cad battery fire . . . 



 Glen: was that the one involving a runaway battery that severed the pitch control system? 



     No . . . at least I don't think so. This airplane

     used two sets of 24 volt ni-cads that were hooked

     in series to get 48 volts to start the engines; then

     reconnected in parallel for normal ops. My mentor, Ken

     Razak asked me to look at the series-parallel switching

     system as a potential root cause of the battery fire.



     The pilot got the airplane down on the ground from about

     10K onto the grass adjacent to a runway. All souls got

     out and the fire crews were able to quickly put out

     the fire.



     Since the system was behaving normally for a departure

     and climb to 10K there was little reason to suspect that

     the series-parallel switching system was 'stuck' in an

     abnormal condition. But given the paralleled generators

     capable of putting many amps into those nice little light

     weight batteries, it was far more likely that the battery

     array suffered thermal runaway and went into self destruction.

     This was the era of before-battery-overheat-monitors.



     Some years later, a technician I hired to work with me

     in the video business mentioned a burned airplane he helped

     restore in Tx. Turns out it was the same MU-2,



     Bob . . .

     [quote][b]

nuckolls.bob(at)aeroelect
Guest

Posted: Fri Oct 14, 2011 6:57 pm Post subject: Electric aircraft issues

Sun Oct 09, 2011 12:36 pm



 

 Hi Bob 



 You mentioned: "The Shorai folks caution against an energetic 

 recharge of a deeply depleted battery." 



 This is not only true of a Lithium battery, but charging a discharged lead acid battery with a high powered alternator that's trying to maintain a constant voltage (just got aeroplane or car running from a jump start) is not very easy on the battery.

  

 How could one limit the charging amps going into the battery yet still allow the alternator to carry any loads? 



 Ron P.



     It's not terribly difficult. We've had generator

     regulators that could not only limit the generator's

     output current . . . but the can current-balance to

     paralleled generators.



     It would not be difficult to design a regulator that

     would limit re-charge current to the battery. This would

     call for a scheduled reduction of bus voltage while the

     really beat battery catches it's breath. The voltage

     would not be so depressed that it hampered normal system

     operations . . . but such a regulator would have prevented

     ni-cad fires and eliminated the need to add the battery overheat

     monitor to ni-cad fitted airplanes.



 

   Bob . . .    [quote][b]

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