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Positively Negative (-) ?

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supik

Joined: 22 Aug 2018
Posts: 70

Posted: Sun Oct 25, 2020 3:48 am Post subject: Positively Negative (-) ?

After reading this article: https://www.kitplanes.com/positively-negative/



I ran a positive and a negative 2awg conductor from the back (battery) of my RV10 to the front. I missed the point where I had to calculate the total cable length for the intermittent starting process.. 



This leaves me with approx. 28ft total 2awg wire length installed. 

-2awg (+) wire from battery to starter and 2awg (-) wire from the engine block to the firewall and from there to the battery. The only airframe negative is grounded at the firewall.



My question is: how much current does the B&C starter draw inrush and continuous to determine whether the 28ft 2awg wire can handle it without too much of voltage drop -thus hurting the starter's performance?



aircraft: RV10

starter: B&C

engine: IO540

battery location: standard behind baggage bulkhead



Thank you

_________________
Igor

RV10 in progress

Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Sun Oct 25, 2020 5:50 am Post subject: Positively Negative (-) ?

You will be fine. You could have dispensed with the ground wire. My 

RV-10 is grounded per the plans, at the battery mount. Use the Vans 

supplied #2 positive wire to firewall mounted starter relay. Have been 

flying 3.5 years on the original Odyssey 925L battery, no problems.

Kelly



On 10/25/2020 4:48 AM, supik wrote:

 	  Quote: 	
		   

 

 After reading this article: https://www.kitplanes.com/positively-negative/

 

 I ran a positive and a negative 2awg conductor from the back (battery) of my RV10 to the front. I missed the point where I had to calculate the total cable length for the intermittent starting process..

 

 This leaves me with approx. 28ft total 2awg wire length installed.

 -2awg (+) wire from battery to starter and 2awg (-) wire from the engine block to the firewall and from there to the battery. The only airframe negative is grounded at the firewall.

 

 My question is: how much current does the B&C starter draw inrush and continuous to determine whether the 28ft 2awg wire can handle it without too much of voltage drop -thus hurting the starter's performance?

 

 aircraft: RV10

 starter: B&C

 engine: IO540

 battery location: standard behind baggage bulkhead

 

 Thank you

 

 --------

 Igor

 

 RV10 in progress

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=498946#498946

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

nuckolls.bob(at)aeroelect
Guest

Posted: Sun Oct 25, 2020 1:16 pm Post subject: Positively Negative (-) ?

At 06:48 AM 10/25/2020, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "supik" <bionicad(at)hotmail.com>



 After reading this article:  https://www.kitplanes.com/positively-negative/



 I ran a positive and a negative 2awg conductor from the back (battery) of my RV10 to the front. I missed the point where I had to calculate the total cable length for the intermittent starting process.. 	


   Igor, please don't do this . . .



   There is no foundation in physics or practice that

   justifies this.



   Yes, the proposed 'upgrades' have some 'advantage'

   but too small to observe and difficult to measure.



   See Figure Z-15 for grounding architectures

   that have successful track records going back

   nearly a century.



 

  	  Quote: 	
		  This leaves me with approx. 28ft total 2awg wire length installed. 

 -2awg (+) wire from battery to starter and 2awg (-) wire from the engine block to the firewall and from there to the battery. The only airframe negative is grounded at the firewall.



 My question is: how much current does the B&C starter draw inrush and continuous to determine whether the 28ft 2awg wire can handle it without too much of voltage drop -thus hurting the starter's performance? 	


    

    "Too much voltage drop" is un-quantified.

    Are you having problems cranking the engine?

    "Hurting starter performance" is also

    un-quantified. No starter EVER expects

    to see 12v in any vehicle. It's a given

    that internal resistance of the battery

    added to cranking path resistance will

    deliver 9-10 volts to the starter. Modern

    starters not withstanding deliver much

    better performance than the legacy 

    tractor starters fitted to most of

    the Lycomings in the years before

    B&C and they got the engine running

    un spite of engine driven fuel pumps,

    manual primer pumps, magnetos with

    impulse couplers, etc. In fact, if

    was skilled at getting the

    variables corraled, the engine could

    be started by hand.



    The quantum jump in modern starter performance

    pretty much eliminates starters as

    a root cause for poor cranking. Adding

    wires in the manner suggested in the article

    is at best, a band-aid on some more

    fundamental problem.

 

   Bob . . .

user9253

Joined: 28 Mar 2008
Posts: 1922
Location: Riley TWP Michigan

Posted: Sun Oct 25, 2020 3:25 pm Post subject: Re: Positively Negative (-) ?

Nobody knows how much current a starter motor will draw, not even the 

manufacturer, because it depends on many variables such as engine 

condition, engine size, temperature, wire size, battery type and size and etc.

_________________
Joe Gores

johnbright

Joined: 14 Dec 2011
Posts: 165
Location: Newport News, VA

Posted: Sun Oct 25, 2020 3:26 pm Post subject: Re: Positively Negative (-) ?

Don't forget to read the description paragraph for Z-15 in the Aeroelectric Connection book. Page Z-4 at http://www.aeroelectric.com/Books/Connection/AppZ_12A3.pdf

_________________
John Bright, RV-6A, at FWF, O-360
Z-101 single batt dual alt SDS EM-5-F.
john_s_bright@yahoo.com, Newport News, Va
N1921R links

supik

Joined: 22 Aug 2018
Posts: 70

Posted: Mon Oct 26, 2020 9:39 am Post subject: Re: Positively Negative (-) ?

Thank you all!



I'll remove the long neg. wire and ground the battery locally.

_________________
Igor

RV10 in progress

DougW

Joined: 16 Sep 2015
Posts: 14
Location: Washington

Posted: Tue Oct 27, 2020 1:51 pm Post subject: Positively Negative (-) ?

This comment may not be relevant as I am not aware of the engine installation.  I have a single alternator dual battery configuration with batteries aft and 2 AWG cables between the batteries and firewall connection.  From the latter connection, I feed the main bus and an e-bus via a diode.  I also have direct switched feeds from the batteries to the e-bus.  I have an electrically dependent automotive fuel injected conversion powerplant.

 

I found that when attempting to start on one battery, I could not get a reliable start.  But when I switched to the second battery directly to the e-bus, no starting problem.  My conclusion is that the voltage drop while cranking the engine was sufficient to cause the ignition system to not operate reliably.  This may have been due to the 9-10v  cranking voltage drop in in addition to the up to 1v drop across the diode.  It is my understanding that most ignition systems need 10v to operate reliably.

 

My current process to start the engine is to crank on the A battery while feeding the B battery directly to the e-bus.  

 

Again, don’t know if this is relevant to this discussion.

 

Regards, Doug Windhorn

 

 

 

From: owner-aeroelectric-list-server(at)matronics.com <owner-aeroelectric-list-server(at)matronics.com> On Behalf Of Robert L. Nuckolls, III

Sent: Sunday, October 25, 2020 11:32 AM

To: aeroelectric-list(at)matronics.com

Subject: Re: Positively Negative (-) ?

 

At 06:48 AM 10/25/2020, you wrote:



 	  Quote: 	
		  

--> AeroElectric-List message posted by: "supik" <bionicad(at)hotmail.com (bionicad(at)hotmail.com)>



After reading this article: https://www.kitplanes.com/positively-negative/



I ran a positive and a negative 2awg conductor from the back (battery) of my RV10 to the front. I missed the point where I had to calculate the total cable length for the intermittent starting process.. 	




  Igor, please don't do this . . .



  There is no foundation in physics or practice that

  justifies this.



  Yes, the proposed 'upgrades' have some 'advantage'

  but too small to observe and difficult to measure.



  See Figure Z-15 for grounding architectures

  that have successful track records going back

  nearly a century.



 	  Quote: 	
		  

This leaves me with approx. 28ft total 2awg wire length installed. 

-2awg (+) wire from battery to starter and 2awg (-) wire from the engine block to the firewall and from there to the battery. The only airframe negative is grounded at the firewall.



My question is: how much current does the B&C starter draw inrush and continuous to determine whether the 28ft 2awg wire can handle it without too much of voltage drop -thus hurting the starter's performance? 	




   

   "Too much voltage drop" is un-quantified.

   Are you having problems cranking the engine?

   "Hurting starter performance" is also

   un-quantified. No starter EVER expects

   to see 12v in any vehicle. It's a given

   that internal resistance of the battery

   added to cranking path resistance will

   deliver 9-10 volts to the starter. Modern

   starters not withstanding deliver much

   better performance than the legacy 

   tractor starters fitted to most of

   the Lycomings in the years before

   B&C and they got the engine running

   un spite of engine driven fuel pumps,

   manual primer pumps, magnetos with

   impulse couplers, etc. In fact, if

   was skilled at getting the

   variables corraled, the engine could

   be started by hand.



   The quantum jump in modern starter performance

   pretty much eliminates starters as

   a root cause for poor cranking. Adding

   wires in the manner suggested in the article

   is at best, a band-aid on some more

   fundamental problem.

  Bob . . .

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Oct 28, 2020 5:02 am Post subject: Positively Negative (-) ?

At 04:43 PM 10/27/2020, you wrote:



  	  Quote: 	
		  This comment may not be relevant as I am not aware of the engine installation.  I have a single alternator dual battery configuration with batteries aft and 2 AWG cables between the batteries and firewall connection.  From the latter connection, I feed the main bus and an e-bus via a diode.  I also have direct switched feeds from the batteries to the e-bus.  I have an electrically dependent automotive fuel injected conversion powerplant.



 I found that when attempting to start on one battery, I could not get a reliable start.  But when I switched to the second battery directly to the e-bus, no starting problem.  My conclusion is that the voltage drop while cranking the engine was sufficient to cause the ignition system to not operate reliably.  This may have been due to the 9-10v  cranking voltage drop in in addition to the up to 1v drop across the diode.  It is my understanding that most ignition systems need 10v to operate reliably. 



 My current process to start the engine is to crank on the A battery while feeding the B battery directly to the e-bus.  



 Again, don’t know if this is relevant to this discussion.

 	
  Very much so . . . but to offer cognizant 

   analysis of your observation, we'd have to

   see a schematic of your distribution system

   and a good physical description of the

   installation.



   Your observations are no doubt accurate

   but anecdotal with respect to cause and

   effect.



   You don't seem to have an issue with

   cranking (starter) performance but instead,

   the ignition system seems especially

   sensitive to low supply voltage. This

   is curious as automotive electronics are

   designed to function under exceedingly

   trying conditions.



   The batteries in automobiles are the

   second worst maintained in practice

   (farm equipment comes first). Any

   automotive designer worth his salt

   strives for state of battery to be

   the last bastion of determination

   for getting ol' bessy fired up.



   If the starter motor achieves

   rotation at all, getting one ideally

   charged cylinder past TDC is going

   to speak to failure/success. Voltage

   to the electrics is generally not

   the limiting factor.



   The article referenced at the start

   of this thread speaks in generalities

   and offers no data that quantifies

   improvements to be secured nor does

   offer anecdotal evidence of a problem

   in practice having been resolved.



   Your narrative at least describes

   actions taken and improvements noted

   as a consequence of that action. But

   it too is short on data that would

   help us understand exactly what

   is happening.



 

 

   Bob . . .

DougW

Joined: 16 Sep 2015
Posts: 14
Location: Washington

Posted: Wed Oct 28, 2020 1:19 pm Post subject: Positively Negative (-) ?

Bob,

 

Thank you for your comments.  I have attached some JPEG images of my relevant schematics.  The originals are .ODG drawings (can’t figure out how to transfer to PDF).  I hope these may help; let me know if there is something else I can provide.  FYI, the numbers interrupting the wires between devices (nodes) are connector pin numbers.

 

Not sure what you mean by “a good physical description of the installation.”  The only thing I can add, not included in the drawings, is that the firewall passthroughs are 5/16” tin-plated threaded studs in an insulated frame mount commonly used by boaters.  Batteries are Odyssey PC680’s.

 

The original electrical installation was done a couple decades ago and generally followed the drawings of the engine converter for those engine related components.  I tried to follow your Z drawings (forgot which one) for overall ships electrical installation.  I have not measured more than about .007 ohms resistance along any of the wires installed, but maybe I should recheck some of those.  

 

Additional notations in your prior response.

 

Doug

 

 

 

From: owner-aeroelectric-list-server(at)matronics.com <owner-aeroelectric-list-server(at)matronics.com> On Behalf Of Robert L. Nuckolls, III

Sent: Wednesday, October 28, 2020 5:57 AM

To: aeroelectric-list(at)matronics.com

Subject: RE: Positively Negative (-) ?

 

At 04:43 PM 10/27/2020, you wrote:

 	  Quote: 	
		  

This comment may not be relevant as I am not aware of the engine installation.  I have a single alternator dual battery configuration with batteries aft and 2 AWG cables between the batteries and firewall connection.  From the latter connection, I feed the main bus and an e-bus via a diode.  I also have direct switched feeds from the batteries to the e-bus.  I have an electrically dependent automotive fuel injected conversion powerplant.



I found that when attempting to start on one battery, I could not get a reliable start.  But when I switched to the second battery directly to the e-bus, no starting problem.  My conclusion is that the voltage drop while cranking the engine was sufficient to cause the ignition system to not operate reliably.  This may have been due to the 9-10v  cranking voltage drop in in addition to the up to 1v drop across the diode.  It is my understanding that most ignition systems need 10v to operate reliably. 



My current process to start the engine is to crank on the A battery while feeding the B battery directly to the e-bus.  



Again, don’t know if this is relevant to this discussion. 	


  Very much so . . . but to offer cognizant 

  analysis of your observation, we'd have to

  see a schematic of your distribution system

  and a good physical description of the

  installation.



  Your observations are no doubt accurate

  but anecdotal with respect to cause and

  effect.



  You don't seem to have an issue with

  cranking (starter) performance (true; should add that the original starter was replaced a few years ago) but instead,

  the ignition system seems especially

  sensitive to low supply voltage. This

  is curious as automotive electronics are

  designed to function under exceedingly

  trying conditions. (The ignition module is an Electromotive Tec2 unit, doubtful that it was intended for automobiles, but….)



  The batteries in automobiles are the

  second worst maintained in practice

  (farm equipment comes first). Any

  automotive designer worth his salt

  strives for state of battery to be

  the last bastion of determination

  for getting ol' bessy fired up.



  If the starter motor achieves

  rotation at all, getting one ideally

  charged cylinder past TDC is going

  to speak to failure/success. Voltage

  to the electrics is generally not

  the limiting factor. (I read somewhere that, in general, ignition modules typically recommended at least 10v to be reliable; don’t know if that is typical or referred to a specific brand module.)



  The article referenced at the start

  of this thread speaks in generalities

  and offers no data that quantifies

  improvements to be secured nor does

  offer anecdotal evidence of a problem

  in practice having been resolved.



  Your narrative at least describes

  actions taken and improvements noted

  as a consequence of that action. But

  it too is short on data that would

  help us understand exactly what

  is happening.  (I’d like to know what’s happening, if only an intellectual exercise.)





  Bob . . .

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Ceengland

Joined: 11 Oct 2020
Posts: 391
Location: MS

Posted: Wed Oct 28, 2020 5:03 pm Post subject: Positively Negative (-) ?

Or, continue to use jpgs, so we can view them within the email instead 

of having to download them & open separately in Adobe.







On 10/28/2020 7:24 PM, Dick Tasker wrote:

 	  Quote: 	
		   

 <dick(at)thetaskerfamily.com>



 If you can print ODG drawings you can use PDF Creator to make a PDF.Â  

 Go to "https://www.pdfforge.org/pdfcreator/download" for the free 

 version.



 I use it to make PDFs from any program that can print.



 Dick Tasker



 n1dw wrote:

>

> Bob,

>

> Thank you for your comments.Â  I have attached some JPEG images of my 

> relevant schematics.Â  The originals are .ODG drawings (canâ€™t figure 

> out how to transfer to PDF).Â  I hope these may help; let me know if 

> there is something else I can provide. FYI, the numbers interrupting 

> the wires between devices (nodes) are connector pin numbers.

>

> Not sure what you mean by â€œa good physical description of the 

> installation.â€Â  The only thing I can add, not included in the 

> drawings, is that the firewall passthroughs are 5/16â€ tin-plated 

> threaded studs in an insulated frame mount commonly used by boaters. 

> Â Batteries are Odyssey PC680â€™s.

>

> The original electrical installation was done a couple decades ago 

> and generally followed the drawings of the engine converter for those 

> engine related components. I tried to follow your Z drawings (forgot 

> which one) for overall ships electrical installation.Â  I have not 

> measured more than about .007 ohms resistance along any of the wires 

> installed, but maybe I should recheck some of those.

>

> Additional notations in your prior response.

>

> Doug

>

> *From:* owner-aeroelectric-list-server(at)matronics.com 

> <owner-aeroelectric-list-server(at)matronics.com> *On Behalf Of *Robert 

> L. Nuckolls, III

> *Sent:* Wednesday, October 28, 2020 5:57 AM

> *To:* aeroelectric-list(at)matronics.com

> *Subject:* RE: Positively Negative (-) ?

>

> At 04:43 PM 10/27/2020, you wrote:

> Â Â Â  This comment may not be relevant as I am not aware of the engine 

> installation.Â  I have a single alternator dual battery configuration 

> with batteries aft and 2 AWG cables between the batteries

> Â Â Â  and firewall connection.Â  From the latter connection, I feed the 

> main bus and an e-bus via a diode.Â  I also have direct switched feeds 

> from the batteries to the e-bus.Â  I have an electrically

> Â Â Â  dependent automotive fuel injected conversion powerplant.

>

> Â Â Â  I found that when attempting to start on one battery, I could not 

> get a reliable start.Â  But when I switched to the second battery 

> directly to the e-bus, no starting problem.Â  My conclusion is

> Â Â Â  that the voltage drop while cranking the engine was sufficient to 

> cause the ignition system to not operate reliably.Â  This may have 

> been due to the 9-10vÂ  cranking voltage drop in in addition to

> Â Â Â  the up to 1v drop across the diode.Â  It is my understanding that 

> most ignition systems need 10v to operate reliably.

>

> Â Â Â  My current process to start the engine is to crank on the A 

> battery while feeding the B battery directly to the e-bus.

>

> Â Â Â  Again, donâ€™t know if this is relevant to this discussion.

>

> Â  Very much so . . . but to offer cognizant

> Â  analysis of your observation, we'd have to

> Â  see a schematic of your distribution system

> Â  and a good physical description of the

> Â  installation.

>

> Â  Your observations are no doubt accurate

> Â  but anecdotal with respect to cause and

> Â  effect.

>

> Â  You don't seem to have an issue with

> Â  cranking (starter) performance (true; should add that the original 

> starter was replaced a few years ago) but instead,

> Â  the ignition system seems especially

> Â  sensitive to low supply voltage. This

> Â  is curious as automotive electronics are

> Â  designed to function under exceedingly

> Â  trying conditions. (The ignition module is an Electromotive Tec2 

> unit, doubtful that it was intended for automobiles, butâ€¦.)

>

> Â  The batteries in automobiles are the

> Â  second worst maintained in practice

> Â  (farm equipment comes first). Any

> Â  automotive designer worth his salt

> Â  strives for state of battery to be

> Â  the last bastion of determination

> Â  for getting ol' bessy fired up.

>

> Â  If the starter motor achieves

> Â  rotation at all, getting one ideally

> Â  charged cylinder past TDC is going

> Â  to speak to failure/success. Voltage

> Â  to the electrics is generally not

> Â  the limiting factor. (I read somewhere that, in general, ignition 

> modules typically recommended at least 10v to be reliable; donâ€™t know 

> if that is typical or referred to a specific brand module.)

>

> Â  The article referenced at the start

> Â  of this thread speaks in generalities

> Â  and offers no data that quantifies

> Â  improvements to be secured nor does

> Â  offer anecdotal evidence of a problem

> Â  in practice having been resolved.

>

> Â  Your narrative at least describes

> Â  actions taken and improvements noted

> Â  as a consequence of that action. But

> Â  it too is short on data that would

> Â  help us understand exactly what

> Â  is happening. (Iâ€™d like to know whatâ€™s happening, if only an 

> intellectual exercise.)

>

> Â  Bob . . .

>






	




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_________________
Charlie

DougW

Joined: 16 Sep 2015
Posts: 14
Location: Washington

Posted: Wed Oct 28, 2020 5:25 pm Post subject: Positively Negative (-) ?

Dick, thanks for the tip.  Have attached the newly created PDF versions.



Doug



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DougW

Joined: 16 Sep 2015
Posts: 14
Location: Washington

Posted: Wed Oct 28, 2020 5:26 pm Post subject: Positively Negative (-) ?

Also a good thought Charlie.  Now I am confused ðŸ˜‰



Doug



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