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Dual Lightspeed Ignition modules

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jpx(at)Qenesis.com
Guest

Posted: Wed Dec 17, 2008 7:45 am Post subject: Dual Lightspeed Ignition modules

I plan dual electronic ignitions for my aircraft.  I started with  

Z13/8.  As much as I expect the designers have done significant things  

to ensure the ignitions work, in spite of nasty power events, I  

finally decided I wanted completely isolated electrical systems, so  

any problem, no matter how unlikely or unpredictable, could not  

prevent continued flight.  So I added a few features from Z14.  I  

didn't go all the way.  My aux battery is very small, and driven by an  

SD-8 alternator.  I did not join the batteries together for extra jolt  

when starting.  I do have a small cross-feed relay that will allow the  

SD-8 to power the essential bus if the main alternator fails.



The biggest thing I wrestled with, was how was my wife to know what  

switches to throw in the event of an alternator failure ?  Together we  

came up with coloured lines joining the warning light and switches  

that are numbered.  This low voltage light goes on, then flip these  

switches in this order.



You can view my power diagram and the switch layout here:

http://www.curtispriest.com/tundra/Electrical



Jeff Page

Dream Aircraft Tundra #10



 	  Quote: 	
		   Speaking of Hall Effect stuff, I just purchased two LightSpeed III hall

 effect ignition modules. The mfg says to connect the + side of the

 controller through a pull-able breaker then directly to the battery

 terminal. Ok, that covers their insurance folks if I crash. On the other

 hand I am using Z-13 and was thinking of using the same scenario but

 connecting them to the main battery bus using an ATC fuse and skipping

 the breaker. I was never a proponent of having extra wires hanging off

 the + side of the battery terminal. AS in Z-13 I will have a switch to

 turn them on/off as necessary.



 Has anyone wired up two of these and which method did you use.



 Glenn

andrewbutler(at)ireland.c
Guest

Posted: Thu Dec 18, 2008 5:00 am Post subject: Dual Lightspeed Ignition modules

Hi Jeff,



I also plan on dual electronic ignition and my original design was practically identical to yours. This was when I was looking at Dual Plasma III Ignitions. Then I switched to dual P-MAGS. Reason? Simplicity and internal power. At this point I couldn't reason that the added complexity of the dual battery split bus was justified, and ended up removing the second battery from the design.



Both the designs are attached, the dual alt, dual batt dating from April. The current design is more or less finished.



Any takers of critiquing it for me?



The originals are in Visio. If anyone wants a copy, let me know.



Cheers, Andrew.



---

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mlas(at)cox.net
Guest

Posted: Thu Dec 18, 2008 10:03 am Post subject: Dual Lightspeed Ignition modules

Andrew,



My two cents!  I have personally seen more EMAG/PMAG failures then total

electrical failure in single bus electrical systems (Z-11).  Add a

secondary battery (Z-19) and the statistics improve for a plasma system

vs. EMAG/PMAG.  Remember during a major electrical failure (for what

ever reason) the Plasma systems only need, is a good battery for more

flying time then the airplane will hold fuel.  The EMAG/PMAG product has

had more then it's fair share of field testing failures by the customer.

A customer that didn't realize they were test subjects.  Just my opinion

viewed with actual 1st party data not 3rd!



Mike Larkin



--

mlas(at)cox.net
Guest

Posted: Thu Dec 18, 2008 10:09 am Post subject: Dual Lightspeed Ignition modules

Glenn,



The reason for wiring the Lightspeed Plasma systems directly to the

battery is to prevent engine failure should you experience a bus failure

(a bus short, over voltage, or heavy drain buy a runaway device.  The

object is that you could simply shut off all electric and continue to

fly (powering the Lightspeed system directly from a battery).  If you

wire the Plasma system to the bus, you would become a glider in the

event of an electrical problem.  In my opinion the Lightspeed dual

system requires two batters in the airplane period.  Anything less will

only serve to help you glider logbook.



Mike Larkin



--

rv9jim(at)juno.com
Guest

Posted: Thu Dec 18, 2008 11:28 am Post subject: Dual Lightspeed Ignition modules

Mike,

        How many failures do you know about with the E-Mag, P-Mag

ignitions?   How many failures of magneto ignitions have occured in the

same time?  Other ignitions of various configurations.  Fact vs: opinion

is very important.  Nothing is perfect.  The main reason we all use dual

ignitions is for safety.  It also gives us better fuel burn.  



Jim

____________________________________________________________

Live the good life! Click now for great retirement planning assistance!

http://thirdpartyoffers.juno.com/TGL2141/fc/PnY6rw1hgimeim0pl7I4CFc1o21Xu2lJFNyMywOmmFBAAdKspEJHz/

jbr79r(at)yahoo.com
Guest

Posted: Thu Dec 18, 2008 12:13 pm Post subject: Dual Lightspeed Ignition modules

I have been using dual Lightspeed ign for about 300 hrs on my Glll with no problems.

Jim Robinson

Glll  N79R



--- On Thu, 12/18/08, James H Nelson <rv9jim(at)juno.com> wrote:

[quote]From: James H Nelson <rv9jim(at)juno.com>

Subject: Dual Lightspeed Ignition modules

To: aeroelectric-list(at)matronics.com

Date: Thursday, December 18, 2008, 12:23 PM



[quote]--> AeroElectric-List message posted by: James H Nelson

<rv9jim(at)juno.com>



Mike,

        How many failures do you know about with the E-Mag, P-Mag

ignitions?   How many failures of magneto ignitions have occured in the

same time?  Other ignitions of various configurations.  Fact vs: opinion

is very important.  Nothing is [quote][b]

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Dec 18, 2008 12:27 pm Post subject: Dual Lightspeed Ignition modules

At 12:06 PM 12/18/2008, you wrote:

 	  Quote: 	
		  



Glenn,



The reason for wiring the Lightspeed Plasma systems directly to the

battery is to prevent engine failure should you experience a bus failure

(a bus short, over voltage, or heavy drain buy a runaway device.  The

object is that you could simply shut off all electric and continue to

fly (powering the Lightspeed system directly from a battery).  If you

wire the Plasma system to the bus, you would become a glider in the

event of an electrical problem.  In my opinion the Lightspeed dual

system requires two batters in the airplane period.  Anything less will

only serve to help you glider logbook.


	


   How do those feared risks occur?



   How do you get a shorted battery bus failure? How does

   connection directly to the battery protect against

   an overvoltage condition? What matter of "runaway

   device" can you imagine that brings the entire system

   to its knees? As long as we're in the free-ranging

   imagination mode, how about bursting batteries,

   open batteries, etc. etc.



   It's easy to hypothesize about all manner of failure

   but the acid test is the repeatable experiment. Get

   any combination of implements you choose and MAKE

   one of those events happen. If it can happen accidently,

   then you can make it happen. If it's exceedingly

   difficult or impossible to MAKE it happen, then concerns

   for accidental events go away. The physics of events do

   not change for random versus purposeful failures.



   Suppose your engine is also dependent upon electrically

   delivered fuel? The path to Nirvana is more than hooking

   certain accessories directly to the battery with some

   notion of fending off nargles. Failure Mode Effects

   Analysis is a science and exercise in logic that has

   served aviation (and others) very well for 100+

   years.



   Making sure the electrically dependent engine is not

   left in dark has been discussed here on the list for

   over ten years. These discussions have included consideration

   of auxiliary batteries both manually and automatically

   controlled.

http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdfs/Z29-30K.pdf



http://www.aeroelectric.com/articles/bat_iso2.pdf



http://www.aeroelectric.com/Catalog/AEC/9005/9005-701B.pdf



    There are well considered rationale for dual

    accessories and power sources that do not concern

    themselves with the statistically improbable or

    physically impossible failure. These were the thought

    processes that went into crafting Z-19 for certain

    kinds of engines.



http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdfs/Z19m_1.pdf



http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdfs/Z19m_2.pdf



    Let us not get bogged down with concerns about why

    and how to tie multiple wires to the battery(+) post.

    There are tried and well tested ways to architecture

    and fabricate an electrical system that grow out

    of confidence of understanding as opposed to nostrums

    that arise out of fear.



    Bob . . .

frank.hinde(at)hp.com
Guest

Posted: Thu Dec 18, 2008 12:36 pm Post subject: Dual Lightspeed Ignition modules

I would agree..There have been a handful of failures, some of those were serious where the E/Pmag lost its timing reference.



There were two reasons for this..One was where the firmware would see a false pressure spike and would then revert to its factory default timing..This was fixed a while ago and seems to have not re-occured.



The other reason was because the magnet was shifting on the end of the shaft. There have been several fixes for this but I believe the lastest one has finally got it. The magnet is now silver soldered on the holder and the holder is keyed to the end of the shaft.



Now of course this latest revision does not have that many hours on it so by default its unproven over the long term but it sure looks like a robust solution.



I have over 300 hours on an E/Pmag combo and did have some early teething troubles. I know have the latest fixes and feel quite comfortable flying behind them.



Frank



--

dale.r(at)cox.net
Guest

Posted: Thu Dec 18, 2008 2:46 pm Post subject: Dual Lightspeed Ignition modules

FWIW dept.



Marc Zeitlin documents the saga of his experiences, 2004 - 2008, with 

the product line.



http://www.cozybuilders.org/Emagair_Warning/index.html



Dale R.

COZY MkIV #0497

Ch. 12



James H Nelson wrote:

 	  Quote: 	
		   



 Mike,

         How many failures do you know about with the E-Mag, P-Mag

 ignitions?   How many failures of magneto ignitions have occured in the

 same time?  Other ignitions of various configurations.  Fact vs: opinion

 is very important.  Nothing is perfect.  The main reason we all use dual

 ignitions is for safety.  It also gives us better fuel burn.  



 Jim

jack.byrne(at)bigpond.com
Guest

Posted: Thu Dec 18, 2008 3:35 pm Post subject: Dual Lightspeed Ignition modules

Dale wrote



 	  Quote: 	
		  FWIW dept.



 Marc Zeitlin documents the saga of his experiences, 2004 - 2008, with the 

 product line.


	


And then there is the silent majority that are happy with their PMAG.

Yes some people have had problems, and there have been teething problems.I 

have had to send mine back for an update.

But I haven't had any problems with mine. I only have 90 Hrs on them but 

many others have 100's of hours on theirs.



Just to balance the argument.



Chris Byrne

andrewbutler(at)ireland.c
Guest

Posted: Fri Dec 19, 2008 2:36 am Post subject: Dual Lightspeed Ignition modules

Hi Mike,



Thanks for this. All two are welcome, as they help build a big picture of all sides of those coins.



I am aware of the issues with the P-Mags (magnets and the like) and this is why I have decided to wire up for dual P-mags, but only install one. This will still give me most of the benefits of the e-ignition, while allowing me to rest easy with regards any gremlins that might exist. I'll let the Slick MAG do its thing and see how things are in a couple of years with regards replacing it............



Cheers, Andrew.

---

mlas(at)cox.net
Guest

Posted: Fri Dec 19, 2008 5:07 am Post subject: Dual Lightspeed Ignition modules

How do those feared risks occur?



   How do you get a shorted battery bus failure? How does

   connection directly to the battery protect against

   an overvoltage condition? What matter of "runaway

   device" can you imagine that brings the entire system

   to its knees? As long as we're in the free-ranging

   imagination mode, how about bursting batteries,

   open batteries, etc. etc.



Lets see, a tool across the bus, or direct short from a chafed wire, the

loss of the ground bus on a composite airplane just to name a few.



I have a story from a dark and stormy night where the air conditioner

started to break down and started to draw over 150 amps and caused both

Gen's to go off line and pull the volts down to about seven volts.  The

CB didn't trip, everything just went almost completely dark before we

got the air conditioner off.  Then we were able to restore power.  The

problem, if we couldn't shut the Air conditioner off or couldn't figure

out the problem in time (if this airplane had a battery powered ignition

system) the engine would have failed, where simply turning the bus off

would have restored the engine or maybe even had enough voltage at the

battery to keep the engine running.  Oh, the airplane referenced was a

certified airplane.



   It's easy to hypothesize about all manner of failure

   but the acid test is the repeatable experiment. Get

   any combination of implements you choose and MAKE

   one of those events happen. If it can happen accidently,

   then you can make it happen. If it's exceedingly

   difficult or impossible to MAKE it happen, then concerns

   for accidental events go away. The physics of events do

   not change for random versus purposeful failures.



Bob, I sometime wonder if you fly or are around flying.  This isn't a

hypothesis; it's based on real people in real airplanes.  The fact is

that electrical systems fail with regularity, some worse then others.

An engine failure on top of that in many cases is a near death

experience.  Loosing the engine is not the same as loosing the

transponder.  Why do we use vacuum or backup batteries to power

important instrument systems?  Don't you think the ignition system

deserves the same respect?



   Suppose your engine is also dependent upon electrically

   delivered fuel? The path to Nirvana is more than hooking

   certain accessories directly to the battery with some

   notion of fending off nargles. Failure Mode Effects

   Analysis is a science and exercise in logic that has

   served aviation (and others) very well for 100+

   years.



It's not!  In aviation failures that occur in the field are often not

reported.  Airplanes with electrical systems have been around for less

the 100 years and electronic ignitions in aviation much less.  We are

all inventing new system designs that are not able to accept total

failure of the total system.



   Making sure the electrically dependent engine is not

   left in dark has been discussed here on the list for

   over ten years. These discussions have included consideration

   of auxiliary batteries both manually and automatically

   controlled.



Yes, but not everyone has been here for 10 years and most of the

products and concepts haven't been either.

 



Mike



10/27/2008 7:57 AM

mlas(at)cox.net
Guest

Posted: Fri Dec 19, 2008 6:20 am Post subject: Dual Lightspeed Ignition modules

I have had direct interaction with four EMAG/PMAG airplanes where the

airplane was unflyable (loss of power in flight, or would not run on the

ground).  I have seen many more mag failures but I have not seen both

fail at the same time making the airplane unflyable. I have also seen

one failure on the Lightspeed system but never a dual failure.  Some of

the EMAG failures may have been isolatable in flight causing a single

failure on a dual system vs. the dual failures that caused landing out

or not running at all.

Mike

--

echristley(at)nc.rr.com
Guest

Posted: Fri Dec 19, 2008 6:37 am Post subject: Dual Lightspeed Ignition modules

Mike wrote:

 	  Quote: 	
		      Making sure the electrically dependent engine is not

    left in dark has been discussed here on the list for

    over ten years. These discussions have included consideration

    of auxiliary batteries both manually and automatically

    controlled.



 Yes, but not everyone has been here for 10 years and most of the

 products and concepts haven't been either.

  

   

That statement shows a lot of insight, Mike.  As the technology we use 
	


evolves, some things that were critical become secondary, and some 

things that were minor become critical.



With respect to electrically dependent (ED) engines, I think we can boil 

all the concerns down to three things that the engine must have to keep 

running:  air, fuel, and spark.  A bulletproof system will have full 

redundancy across all three.



Redundant air is generally provided by some sort of flapper valve or 

some such thingy to get around a clogged air filter, but the biggest 

problem with air is carb icing.  This is one area where electronic 

injection shines.  A significant portions of accidents occur when a carb 

ices up where the fuel is evaporated into the air.  EI moves the 

evaporation location closer to the combustion location, where there is 

more heat to keep the ice from forming.  Icing is still possible, just 

less so.  Either way, methods for avoiding cutting off the air supply 

look the same for all types of engines.



Redundant fuel is harder for ED engines.  Fuel pumps are hard working 

devices that are reliable, but do not have infinite lifespan, and it 

depends on a lot of upstream stuff to work.  A backup pump only backs up 

the pump.  For it to be a true alternate system, you have to backup 

everything, up to and including the power generation source.  Even with 

a second pump, I chose to go low tech and provide a gravity fed drip 

line to the air intake with a needle valve control.  I would never be 

able to get the engine started with this on the ground...and I'd never 

want to.  Control is slow and unresponsive, but it will get me to the 

nearest airport.  It is meant as a backup to keep the fan turning in an 

emergency.  This would work for any engine.  Low wing aircraft would 

need a header tank higher than the engine.  The vast majority of 

aircraft being built in garages today could stay straight and level for 

an hour with 5gal of fuel, and travel nearly 100 miles.  At a time when 

everything is going that badly the only place you should be trying to 

get to is 'nearest'.  High wing aircraft would be able to run the tanks 

dry with this method.



The spark is also more difficult for ED.  Airplane engines are designed 

with two independent, self contained spark producers.  Each mag has a 

generator, a distributor and coil all in one tidy package.   You just 

have to bolt them on and plug them in.  Moving to ED generally means 

that you're breaking the generator and spark producer apart.  Most 

designs have two spark producers, but combine the generators into one, 

and depend on the battery for backup.  Again, this isn't really 

redundancy.  My design calls for using two EDIS modules (self-contained 

electronic ignition controller used by Ford), and converting the old 

distributor to a generator.  One EDIS module runs off ship's power.  The 

other is powered by the tiny generator (less than 5 amps) that was once 

the distributor.  If I lose ship's power, the secondary ignition will 

keep right on going.  The two are completely independent.



So Mike is correct.  New products call for new thinking...but the 

thinking really goes back to the same basic principles.  The engine must 

have air, spark and fuel.  Backup systems must be able to deliver 

without depending on the primary system.  It is best to assume that the 

primary system doesn't exist AT ALL when designing the backup.  There's 

a lot of new under the sun....just it's not, really.

longg(at)pjm.com
Guest

Posted: Fri Dec 19, 2008 9:39 am Post subject: Dual Lightspeed Ignition modules

Mike and Bob,



Thank you both for your input. I have emailed with Jeff P. and I've

decided a second battery (even a small 4.5 ah job) would be a good idea

as an independent source for keeping at least one ignition going even if

I shut down the power completely and simply had to fly home with just

the engine. 



Mike, as you indicated that is the reason Lightspeed likes it wired

directly to the battery. Depending on a bus which is behind a solenoid

is asking for trouble. Yes, I've replaced more than one solenoid on

aircraft in the field and fortunately with mags there was no dependency.

FYI, stealing a solenoid off the FBOs old pick-up truck works in

airplanes too. Parts do fail, but only when you're flying - funny that.



The Lightspeed draws little power and I only need 1-2 amps to find a

landing spot. It may be that I install it inside the cabin and keep it

charged just as a backup. A big part of the process is monitoring and

recognizing when the system is acting up and when (and how) to shut it

down - that's process. I have done enough flying in the dark to realize

the importance of a backup something. 



Thanks to all for the diagrams and discussion.



Glenn



--

nuckolls.bob(at)aeroelect
Guest

Posted: Fri Dec 19, 2008 11:43 am Post subject: Dual Lightspeed Ignition modules

At 07:01 AM 12/19/2008, you wrote:

 	  Quote: 	
		  

    How do those feared risks occur?



    How do you get a shorted battery bus failure? How does

    connection directly to the battery protect against

    an overvoltage condition? What matter of "runaway

    device" can you imagine that brings the entire system

    to its knees? As long as we're in the free-ranging

    imagination mode, how about bursting batteries,

    open batteries, etc. etc.



Lets see, a tool across the bus, or direct short from a chafed wire, the

loss of the ground bus on a composite airplane just to name a few.


	


      . . . and are these all not manifestations of poor

      craftsmanship or maintenance?  If we're going to add

      band-aids to any system that go to offsetting sub-standard

      behavior by someone who has touched the airplane . . . where

      does it end?



 	  Quote: 	
		  I have a story from a dark and stormy night where the air conditioner

started to break down and started to draw over 150 amps and caused both

Gen's to go off line and pull the volts down to about seven volts.  The

CB didn't trip, everything just went almost completely dark before we

got the air conditioner off.  Then we were able to restore power.  The

problem, if we couldn't shut the Air conditioner off or couldn't figure

out the problem in time (if this airplane had a battery powered ignition

system) the engine would have failed, where simply turning the bus off

would have restored the engine or maybe even had enough voltage at the

battery to keep the engine running.  Oh, the airplane referenced was a

certified airplane.


	


     . . . and what did you learn from this or any other story

     that would give you pause for evaluating your own project?

     Are there things that could or should have been done in

     the original design processes that would have prevented this

     incident? Suppose your RV doesn't even HAVE a piece-of-(at)#$(at)#

     air conditioner.What is the value of taking one incident where

     the designers/fabricators/maintainers/operators stubbed there

     collective toes and then levying new requirements on ALL

     airplanes that work-around the SYMPTOMS of that one case?

 	  Quote: 	
		  Bob, I sometime wonder if you fly or are around flying.  This isn't a

hypothesis; it's based on real people in real airplanes.  The fact is

that electrical systems fail with regularity, some worse then others.

An engine failure on top of that in many cases is a near death

experience.  Loosing the engine is not the same as loosing the

transponder.  Why do we use vacuum or backup batteries to power

important instrument systems?  Don't you think the ignition system

deserves the same respect?


	


     My career in aviation began in 1955 when I helped

     an uncle install an MANUAL direction finder loop in

     his 170. He could put holes in the airplane but couldn't

     read a diagram or solder. I was 12 years old.



     I retired from Hawker-Beechcraft 18 months ago as the

     subject matter expert leader in electronics/electrical

     systems. I'm still contracting to that organization and

     several others who specialize in aviation design and

     production.



     I'm an 1000 hour private pilot with about that many

     additional hours as a test engineer on TC aircraft

     and 50 times that time as a designer, qualifier and

     troubleshooter of airborne systems. I'm now 66 years

     old and still in the business.



 	  Quote: 	
		  It's not!  In aviation failures that occur in the field are often not

reported.  Airplanes with electrical systems have been around for less

the 100 years and electronic ignitions in aviation much less.  We are

all inventing new system designs that are not able to accept total

failure of the total system.


	


      Agreed. But just as fuel flow under all anticipated

      flight conditions was the big stumbling block for

      many a designer 70 years ago, we have a new

      challenge that isn't any different.  Just as there's

      no excuse for total failure of fuel flow, there is

      NO EXCUSE for total failure of an electrical system.

      Yeah, it has happened which means there's a REASON

      but there is still no excuse.



 	  Quote: 	
		  Yes, but not everyone has been here for 10 years and most of the

products and concepts haven't been either.


	


      Just because it is new doesn't mean that the

      thought processes and fabrication techniques

      for airworthiness are any different than what

      has worked well for decades.



      Suppose we consider an RV with a piece of (at)#$(at)

      air conditioner with a failure mode that sucks down

      the entire system? Of what value is it to tie

      one or both systems directly to the (+) battery

      post? Which is better, refine the A/C design or

      add weight, complexity, cost-of-ownership to offset

      the possibility that the A/C causes an unhappy day

      in the cockpit?



      On a related topic. Lots of folks are trying to figure

      out ways to integrate lithium-ion batteries into

      aircraft. It's no mean task. While the energy/weight

      radio of l-ion is seductive, it's sorta like figuring

      out a way to burn nitro-glycerine in your engine. Wow!

      What energy potential! Now, how do you integrate

      this potential into an existing, highly refined system

      in a way that does not increase risk?



      There are people who worry a lot about things

      they don't understand. There are people who are

      paid to worry a lot about things they presumably

      understand and use force of law to modify our

      behavior such that THEIR worries are mitigated

      . . . all in the name of 'safety'.



http://www.hsegroup.com/hse/text/caffiene.htm



http://aeroelectric.com/Pictures/Misc/Cowboy_after_OSHA.jpg



      My point about your posting was that it tended to

      reenforce the notion that there was a valid WORRY

      to be address without adding understanding.

      An understanding of design for failure-tolerance,

      craftsmanship, maintenance and operation such that

      worries go away.



      There are few suppliers to aviation that have a

      working knowledge of low-risk, light-weight, failure-

      tolerant system design. If we attached every worry-wart's

      product to the battery(+) post . . . it's easy

      to see where that idea leads!



      Bob . . .

longg(at)pjm.com
Guest

Posted: Mon Dec 22, 2008 9:20 am Post subject: Dual Lightspeed Ignition modules

Ah, good point Bob. I think as long as aircraft and human nature exist,

there is no end. One gets the impression that by introducing new

technology we somehow lesson our faith in its reliability. 



I embrace new technology, but I don't want to have to build a

triple-redundant system on the chance it may take a bow. The goal of

simplicity with reliability should still be enforced.



Glenn



--

mjpereira68(at)gmail.com
Guest

Posted: Mon Dec 22, 2008 2:05 pm Post subject: Dual Lightspeed Ignition modules

 	  Quote: 	
		        On a related topic. Lots of folks are trying to figure

      out ways to integrate lithium-ion batteries into

      aircraft. It's no mean task. While the energy/weight

      radio of l-ion is seductive, it's sorta like figuring

      out a way to burn nitro-glycerine in your engine. Wow!

      What energy potential! Now, how do you integrate

      this potential into an existing, highly refined system

      in a way that does not increase risk?


	


Oh good lord, li-poly batteries are awesome for *model*

aviation. I hope the manufacturers you're alluding to are

considering the "A123 Systems" type chemistry batteries (which

will take abuse without emiting a napalm like lithium/cobalt

fog).

Terry Watson

Joined: 09 Jan 2006
Posts: 290
Location: Seattle, WA USA

Posted: Mon Dec 22, 2008 2:59 pm Post subject: Dual Lightspeed Ignition modules

Here is something from the archives. I think it followed a poll where Bill

Dube was asking how many of us would be interested in a really good aircraft

battery at a relatively high price:



Sep 07, 2007 From:  Bill Dube <William.P.Dube(at)noaa.gov> Subject:  Re:

A123 Systems Nano-phosphate technology and aircraft 

(was: KillaCycle  on Dish Net Tonight)

Whomever is designing the electronics doesn't have real experience with 

A123 Systems cells. They think they are dealing with conventional Li-Ion 

cells, and they are wrong.



    A123 Systems nano-phosphate cells are quite different than other 

Li-Ion cells. They will take a LOT of abuse. About the same amount as an 

AGM. It is straightforward to make a drop-in replacement for a 12 volt 

(or 24 volt) lead-acid battery using A123 Systems cells. The existing 

charging system will work just fine. (It must have the voltage set 

somewhere between 13.5 and 14.8 volts.)



    In an airplane, you would want a warning that alerted the pilot that 

the system was going over 14.8 volts and would make noise if the system 

was going over 15 volts. It would also be useful to know if the battery 

temperature was going over 80 Celsius. (You can go up to about 100 C 

without damage, but no higher or you risk venting the cells and damaging 

the plastic separator.)



 >>> Case study <<<<

    I have had a 3.5 lb A123 Systems battery running in my completely 

unmodified GMC van for the past 7 months. It snaps the engine over much 

better than the original 35 lb lead-acid battery.



    Let's talk about abuse. My wife left my van door unlocked and 

someone rifled my glove box and left it open with the light on. This 

killed the battery and it sat at ZERO VOLTS for over a week. I thought, 

"So much for THAT battery." I then decided to do what the typical 

consumer would do and I connected up the 3.5 lb completely dead battery 

to a fully-charged car battery with jumper cables. Hundreds of amps 

flowed and slightly warmed the cables. I waited a couple of minutes for 

the 3.5 lb battery voltage to come up, disconnected the jumper cables 

(the worst thing you could do) and cranked up the van. It started 

instantly. The alternator then gave the 3.5 lb battery ~100 amps until 

it came up to 13.4 volts and then tapered off. The BMS showed that all 

the cells were still in balance!



    This was five months ago. I haven't capacity-tested the battery, but 

I can't tell the difference in cranking performance. It was just as if 

nothing had happened. I even left it parked for 5 weeks while I was out 

of town and it cranked right up without a problem.



    If you were to torture a conventional Li-Ion battery like this, it 

would have burst into flames, or at least it would have just burst. I 

tell this story to folks with years of experience with conventional 

Li-Ion cells and they cringe when I get to the part about the jumper 

cables. 



    The A123 Systems cells will, indeed, "take the abuse". I have a very 

simplistic charge-balancing electronics (BMS) on my GMC van battery. 

Nothing fancy is needed.



    If you overcharge them grossly, they will vent a small amount of 

flammable vapor (like paint thinner.) If there is an ignition source, 

this vapor could catch fire. The cells can also burst if overcharged 

severely. That is the extent of the hazard this technology presents.



Bill Dube'

   

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