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Z-13/8 Failure Question

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BMC_Dave

Joined: 04 Jul 2018
Posts: 40

Posted: Fri Jul 06, 2018 2:00 pm Post subject: Z-13/8 Failure Question

Been pouring through the forums recently, lots of great info and I've been able to answer most of my own questions so far. I'm curious about a particular failure since I'm designing for a SDS EI/EFI plane, perhaps I don't fully understand how the LR-3 module works.



In Z-13/8 if the battery contactor fails, exceedingly rare and probably with some warning prior to being critical, is there any notification that such a failure has occurred? Any indication the battery has been disconnected from the main ALT?



I'll be switching the SDS system off the main battery bus. So if what I'm thinking is true I won't get any indication I'm running the engine only off battery power until it stops. An unappealing prospect...



Also, looking at the reference figures online are these Z-figures the most recent? I ask because it seems the wiring for the main ALT in Z-13 doesn't include the LR-3 module, I have to look at Z-12 for that. Not hard to modify for the combined module, just wondering if there is a Z-13 version out there that includes this. Thanks!

ceengland7(at)gmail.com
Guest

Posted: Fri Jul 06, 2018 2:17 pm Post subject: Z-13/8 Failure Question

On Fri, Jul 6, 2018 at 5:01 PM, BMC_Dave <bmcdave85(at)gmail.com (bmcdave85(at)gmail.com)> wrote:

 	  Quote: 	
		  --> AeroElectric-List message posted by: "BMC_Dave" <bmcdave85(at)gmail.com (bmcdave85(at)gmail.com)>

 

 Been pouring through the forums recently, lots of great info and I've been able to answer most of my own questions so far. I'm curious about a particular failure since I'm designing for a SDS EI/EFI plane, perhaps I don't fully understand how the LR-3 module works.

 

 In Z-13/8 if the battery contactor fails, exceedingly rare and probably with some warning prior to being critical, is there any notification that such a failure has occurred? Any indication the battery has been disconnected from the main ALT?

 

 I'll be switching the ECU and injectors off the main battery bus. So if what I'm thinking is true I won't get any indication I'm running the engine only off battery power until it stops. An unappealing prospect...

 

 Also, looking at the reference figures online are these Z-figures the most recent? I ask because it seems the wiring for the main ALT in Z-13 doesn't include the LR-3 module, I have to look at Z-12 for that. Not hard to modify for the combined module, just wondering if there is a Z-13 version out there that includes this. Thanks!

 

 

	
z-13 is 'on a budget'. the Ford regulator is tens of dollars instead of hundreds of dollars.   If you're going to use the LR-3, then just draw it and its accessories in place of the Ford regulator. If you're keeping the Ford regulator, just add an inexpensive low voltage detector/indicator to the battery bus. Or, if you have an EFIS and/or engine monitor, it should be able to announce undervoltage due to loss of alternator power (which is the actual concern, right?).

BMC_Dave

Joined: 04 Jul 2018
Posts: 40

Posted: Fri Jul 06, 2018 2:31 pm Post subject: Re: Z-13/8 Failure Question

 	  ceengland7(at)gmail.com wrote: 	
		  z-13 is 'on a budget'. the Ford regulator is tens of dollars instead of hundreds of dollars.   If you're going to use the LR-3, then just draw it and its accessories in place of the Ford regulator. If you're keeping the Ford regulator, just add an inexpensive low voltage detector/indicator to the battery bus. Or, if you have an EFIS and/or engine monitor, it should be able to announce undervoltage due to loss of alternator power (which is the actual concern, right?).  	




Ah, I get the schematic now. Though the B&C website "All Electric On A Budget" includes the LR-3... and a 60A main ALT.



Yeah I'll have dual EFISs but they'll be off the e-buss, well one will at least, and would be seeing the ALT voltage from there with the BAT contact open. I assume from their perspective nothing would change when the BAT is disconnected, though I'm likely misunderstanding.



ETA: Sorry, just to clarify the alternator failing isn't what I'm asking. I'm asking about a battery contact failure and whether I'd have any indication that battery, which is critical to keep the fan up front spinning, is being depleted. Looking at the LR-3 it seems to be sensing buss voltage on terminal 5/3, so I would think you could just move this to the battery bus and it would have the desired effect. This would now be independent of the battery contactor. I'm just starting to get into all this so I could just be plane wrong

user9253

Joined: 28 Mar 2008
Posts: 1921
Location: Riley TWP Michigan

Posted: Fri Jul 06, 2018 3:21 pm Post subject: Re: Z-13/8 Failure Question

Many, if not most, alternators will keep working if the battery is disconnected.  Electrical loads draw their current from the source with the highest voltage.  Since the alternator puts out a higher voltage than the battery does, everything including the alternator field is powered by the alternator.  If the battery is disconnected, then its stabilizing affect is lost.  The voltage from the alternator might vary about plus or minus a volt.  A symptom of battery contactor failure could be unstable voltage.  If the E-Bus switch is normally turned on, then another symptom of contactor failure is a drop in voltage between 0.5 and 1 volt (across the diode).

  If the E-Bus is still connected to the battery, then its voltage might remain stable.  But the voltage on the main power bus could be unstable with the battery disconnected.

  Battery contactors do not fail very often.

_________________
Joe Gores

BMC_Dave

Joined: 04 Jul 2018
Posts: 40

Posted: Fri Jul 06, 2018 3:35 pm Post subject: Re: Z-13/8 Failure Question

 	  user9253 wrote: 	
		  Many, if not most, alternators will keep working if the battery is disconnected.  Electrical loads draw their current from the source with the highest voltage.  Since the alternator puts out a higher voltage than the battery does, everything including the alternator field is powered by the alternator.  If the battery is disconnected, then its stabilizing affect is lost.  The voltage from the alternator might vary about plus or minus a volt.  A symptom of battery contactor failure could be unstable voltage.  If the E-Bus switch is normally turned on, then another symptom of contactor failure is a drop in voltage between 0.5 and 1 volt (across the diode).

  If the E-Bus is still connected to the battery, then its voltage might remain stable.  But the voltage on the main power bus could be unstable with the battery disconnected.

  Battery contactors do not fail very often. 	




This is all consistent with my assumptions. So indeed it is possible to have the battery contactor fail, have nothing on the e-bus or main bus side notice, and keep chugging along until your engine suddenly quits (because your entire ignition and fuel delivery system is dependent on the battery bus). Is this correct?

ceengland7(at)gmail.com
Guest

Posted: Fri Jul 06, 2018 3:58 pm Post subject: Z-13/8 Failure Question

On 7/6/2018 6:35 PM, BMC_Dave wrote:

 	  Quote: 	
		   

 user9253 wrote:

> Many, if not most, alternators will keep working if the battery is disconnected.  Electrical loads draw their current from the source with the highest voltage.  Since the alternator puts out a higher voltage than the battery does, everything including the alternator field is powered by the alternator.  If the battery is disconnected, then its stabilizing affect is lost.  The voltage from the alternator might vary about plus or minus a volt.  A symptom of battery contactor failure could be unstable voltage.  If the E-Bus switch is normally turned on, then another symptom of contactor failure is a drop in voltage between 0.5 and 1 volt (across the diode).

>    If the E-Bus is still connected to the battery, then its voltage might remain stable.  But the voltage on the main power bus could be unstable with the battery disconnected.

>    Battery contactors do not fail very often.



 This is all consistent with my assumptions. So indeed it is possible to have the battery contactor fail, have nothing on the e-buss or main buss side notice, and keep chugging along until your engine suddenly quits (because your entire ignition and fuel delivery system is dependent on the battery buss). Is this correct?

If you don't have anything on the battery bus that will detect loss of 
	


alternator power, then just add low voltage detection to the battery 

bus. Having said that, I believe that Ross has said SDS' new system, 

still in development, will have low voltage annunciation and auto 

switching to a backup battery. Have you asked about that feature?



Charlie



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user9253

Joined: 28 Mar 2008
Posts: 1921
Location: Riley TWP Michigan

Posted: Fri Jul 06, 2018 4:02 pm Post subject: Re: Z-13/8 Failure Question

Not necessarily.  Since you have two EFISs, monitor the E-Bus voltage with one and the main bus with the other.  If the voltage drops by even 1/2 volt, then land.  Lithium batteries are different than lead acid.  Lithium batteries maintain their voltage until almost dead.  If the engine is electrically dependent, then any abnormal voltage should be reason to land and troubleshoot on the ground.

_________________
Joe Gores

user9253

Joined: 28 Mar 2008
Posts: 1921
Location: Riley TWP Michigan

Posted: Fri Jul 06, 2018 4:16 pm Post subject: Re: Z-13/8 Failure Question

If you want to back up the battery contactor, the attached drawing is one way.  

The small relay is disabled during engine cranking to prevent overloading its contacts.

I am not necessarily recommending this circuit, just offering it as an option.

Contactor Bypass.jpg

Description:

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_________________
Joe Gores

user9253

Joined: 28 Mar 2008
Posts: 1921
Location: Riley TWP Michigan

Posted: Fri Jul 06, 2018 4:19 pm Post subject: Re: Z-13/8 Failure Question

My 6-year-old Odyssey PC680 failed open while flying. The result was the same as if the battery contactor failed.

_________________
Joe Gores

BMC_Dave

Joined: 04 Jul 2018
Posts: 40

Posted: Fri Jul 06, 2018 4:29 pm Post subject: Re: Z-13/8 Failure Question

Definitely not looking to add another contactor. I suppose you could set up the efis to monitor engine bus, but why not just hook the LR-3 to it instead? Then instead of just telling us the alternator is working it also tells us if it's charging the battery. Reduced part counts is always nice too...



That would render any low voltage warnings from SDS unnecessary.

user9253

Joined: 28 Mar 2008
Posts: 1921
Location: Riley TWP Michigan

Posted: Fri Jul 06, 2018 4:46 pm Post subject: Re: Z-13/8 Failure Question

There was a recent discussion on VansAirforce about electrical architecture for EFI with lots of opinions and suggestions.

http://www.vansairforce.com/community/showthread.php?t=151435

_________________
Joe Gores

rnjcurtis(at)charter.net
Guest

Posted: Fri Jul 06, 2018 4:50 pm Post subject: Z-13/8 Failure Question

My 6-year-old Odyssey failed open while flying.  The result was the same as if the battery contactor failed.

 

--------

Joe Gores

 

              I believe that it would not be quite the same thing.  If you have an electrically dependent engine, in your case, the alternator power would back feed through the contactor to the battery bus and keep the engine running as long as you didn’t try to draw more current than the alternator can supply.

 

Roger

user9253

Joined: 28 Mar 2008
Posts: 1921
Location: Riley TWP Michigan

Posted: Fri Jul 06, 2018 5:02 pm Post subject: Re: Z-13/8 Failure Question

Right you are Roger.  Luckily my Rotax 912ULS engine has its own independent ignition system and engine driven fuel pump.

_________________
Joe Gores

BMC_Dave

Joined: 04 Jul 2018
Posts: 40

Posted: Fri Jul 06, 2018 5:02 pm Post subject: Re: Z-13/8 Failure Question

 	  user9253 wrote: 	
		  There was a recent discussion on VansAirforce about electrical architecture for EFI with lots of opinions and suggestions.

http://www.vansairforce.com/community/showthread.php?t=151435 	




I appreciate that. I am still interested in the answer to my question about this specific architecture though.

yellowduckduo(at)gmail.co
Guest

Posted: Sat Jul 07, 2018 4:07 am Post subject: Z-13/8 Failure Question

For my EFI with dual alternators configured similar to Z-14, I have both 

alternators connected to the battery side of the contactors. Seemed 

reasonable to me since each of my alts are disconnected when their 

respective alternator switch is turned off. The main one via an 

overvoltage disconnect contactor and the second smaller one via a 40 amp 

relay.  ie. they will both charge even if the "battery" contactor is off.



My EIS monitors the left battery buss and the EIS is itself powered by 

the main distribution buss so immediate notification occurs if an alt 

drops offline.  If the battery contactor opens I do lose the EIS and the 

warnings but then the dead EIS is the warning. The EIS is not essential 

for me. Even if the main alternator stopped charging or the main battery 

failed on the same flight I can run on the second alternator and battery 

indefinitely albeit without the EIS. I have hand held nav and comm 

backups and I have one switched cig lighter outlet powered from the 

other battery buss. It can power handheld devices or I can plug in a $4. 

voltmeter that is sold for monitoring automotive electrical systems. Now 

that I no longer have any vacuum powered instruments I would have to 

look at adding a second power source for the EIS and avionics if I still 

did any IFR flying.



As others have said, you definitely need something that immediately 

notifies you that the battery buss voltage is below normal charging 

voltage. Mine trigger if the alternator is not maintaining it at greater 

than 13.5 volts.



Ken



On 06/07/2018 6:01 PM, BMC_Dave wrote:

 	  Quote: 	
		   



 Been pouring through the forums recently, lots of great info and I've been able to answer most of my own questions so far. I'm curious about a particular failure since I'm designing for a SDS EI/EFI plane, perhaps I don't fully understand how the LR-3 module works.



 In Z-13/8 if the battery contactor fails, exceedingly rare and probably with some warning prior to being critical, is there any notification that such a failure has occurred? Any indication the battery has been disconnected from the main ALT?



 I'll be switching the ECU and injectors off the main battery bus. So if what I'm thinking is true I won't get any indication I'm running the engine only off battery power until it stops. An unappealing prospect...



 Also, looking at the reference figures online are these Z-figures the most recent? I ask because it seems the wiring for the main ALT in Z-13 doesn't include the LR-3 module, I have to look at Z-12 for that. Not hard to modify for the combined module, just wondering if there is a Z-13 version out there that includes this. Thanks!





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=481447#481447



 .

nuckolls.bob(at)aeroelect
Guest

Posted: Sat Jul 07, 2018 7:54 am Post subject: Z-13/8 Failure Question

At 05:01 PM 7/6/2018, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "BMC_Dave" <bmcdave85(at)gmail.com>



 Been pouring through the forums recently, lots of great info and I've been able to answer most of my own questions so far. I'm curious about a particular failure since I'm designing for a SDS EI/EFI plane, perhaps I don't fully understand how the LR-3 module works. 	


   The LR3C alternator controller is an adjustable

   linear regulator combined with crowbar over voltage

   protection and low voltage warning.



 

  	  Quote: 	
		  In Z-13/8 if the battery contactor fails, exceedingly rare and probably with some warning prior to being critical, is there any notification that such a failure has occurred? Any indication the battery has been disconnected from the main ALT? 	


   No. You probably won't be aware of a battery contactor

   failure until you're on the ground and just happen

   to shut alternator(s) down first . . . or attempt

   a preflight for your next sortie. 



 

  	  Quote: 	
		  I'll be switching the ECU and injectors off the main battery bus. So if what I'm thinking is true I won't get any indication I'm running the engine only off battery power until it stops. An unappealing prospect... 	


   Add lv warning to the battery bus . . .



   https://goo.gl/sNBCja

 

   You would hook such a gizmo to the downstream

   side of one of the engine accessory switches

   such that the lv warn gets powered down with

   the engine.



  	  Quote: 	
		  Also, looking at the reference figures online are these Z-figures the most recent? I ask because it seems the wiring for the main ALT in Z-13 doesn't include the LR-3 module, I have to look at Z-12 for that. Not hard to modify for the combined module, just wondering if there is a Z-13 version out there that includes this. Thanks! 	


   The Z figures are ARCHITECTURE drawings, not wire books

   nor are they intended to drive decisions for selection of specific

   components. One might use any combination of ov/lv/regulator

   in lieu of the LR3 and vise-versa.



   Battery contactor failure in flight is exceedingly rare.

   They nearly always annunciate impending failure during

   an engine start. But be attentive to the FIRST signs

   of fussiness . . . I had a renter on 1K1 that would

   go rap on his Cherokee battery contactor with the handle

   of a screwdriver with the master switch ON . . . seems

   that this shade tree mechanic's move gave him better

   starts. We moved off the airport before the contactor

   went TU so I don't know how long the work-around serviced

   his intentions to go flying.



   Contactors I've replaced had been in service years . . .

   sometimes decades. Teardown inspections showed that

   the devices were pretty beat up. Whisky barrel contactors

   are best mounted cap down . . . with a small vent/drain

   hole added to the hi-point of the cap.



   Works good . . . lasts a long time . . . 



 

 

   Bob . . .

BMC_Dave

Joined: 04 Jul 2018
Posts: 40

Posted: Sun Jul 08, 2018 8:29 am Post subject: Re: Z-13/8 Failure Question

 	  nuckolls.bob(at)aeroelect wrote: 	
		  At 05:01 PM 7/6/2018, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "BMC_Dave" <bmcdave85>



 Been pouring through the forums recently, lots of great info and I've been able to answer most of my own questions so far. I'm curious about a particular failure since I'm designing for a SDS EI/EFI plane, perhaps I don't fully understand how the LR-3 module works. 	


   The LR3C alternator controller is an adjustable

   linear regulator combined with crowbar over voltage

   protection and low voltage warning.



 

  	  Quote: 	
		  In Z-13/8 if the battery contactor fails, exceedingly rare and probably with some warning prior to being critical, is there any notification that such a failure has occurred? Any indication the battery has been disconnected from the main ALT? 	


   No. You probably won't be aware of a battery contactor

   failure until you're on the ground and just happen

   to shut alternator(s) down first . . . or attempt

   a preflight for your next sortie. 



 

  	  Quote: 	
		  I'll be switching the ECU and injectors off the main battery bus. So if what I'm thinking is true I won't get any indication I'm running the engine only off battery power until it stops. An unappealing prospect... 	


   Add lv warning to the battery bus . . .



   https://goo.gl/sNBCja

 

   You would hook such a gizmo to the downstream

   side of one of the engine accessory switches

   such that the lv warn gets powered down with

   the engine.



  	  Quote: 	
		  Also, looking at the reference figures online are these Z-figures the most recent? I ask because it seems the wiring for the main ALT in Z-13 doesn't include the LR-3 module, I have to look at Z-12 for that. Not hard to modify for the combined module, just wondering if there is a Z-13 version out there that includes this. Thanks! 	


   The Z figures are ARCHITECTURE drawings, not wire books

   nor are they intended to drive decisions for selection of specific

   components. One might use any combination of ov/lv/regulator

   in lieu of the LR3 and vise-versa.



   Battery contactor failure in flight is exceedingly rare.

   They nearly always annunciate impending failure during

   an engine start. But be attentive to the FIRST signs

   of fussiness . . . I had a renter on 1K1 that would

   go rap on his Cherokee battery contactor with the handle

   of a screwdriver with the master switch ON . . . seems

   that this shade tree mechanic's move gave him better

   starts. We moved off the airport before the contactor

   went TU so I don't know how long the work-around serviced

   his intentions to go flying.



   Contactors I've replaced had been in service years . . .

   sometimes decades. Teardown inspections showed that

   the devices were pretty beat up. Whisky barrel contactors

   are best mounted cap down . . . with a small vent/drain

   hole added to the hi-point of the cap.



   Works good . . . lasts a long time . . . 



 

 

   Bob . . . 	




Awesome, that about covers my concerns. Thanks!

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