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Neg Battery Cable Routing

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orchidman

Joined: 10 Jul 2006
Posts: 277
Location: Oklahoma City - KRCE

Posted: Tue Mar 18, 2008 11:05 am Post subject: Neg Battery Cable Routing

I am trying to wrap up the design of the Negative battery lead from the battery to the starter.  I have two specific questions.



From the Neg terminal of the battery, Vans shows that you go to airframe ground at the battery mount frame and that is all.  Others have a Neg cable paralleling the Pos cable to the firewall where the Neg lead is grounded to the firewall.  I am considering grounding at the battery mount frame and continuing the cable forward to the firewall.  My first question is, how many are running 2 cables and if so, are you grounding at both locations?  I ask this because in theory it is creating a ground loop.



When the Neg cable gets to the firewall I will terminate it with a brass bolt through the firewall.  There, I will be able to attach tabbed ground strips on both sides of the firewall for grounding radios, etc.



The engine will be grounded to the engine mount with Vanâ€™s grounding strap (I think it is P-25).  My second question is about a cable from the forward side of the firewall Neg brass bolt to either one of the engine mounting bolts or to the P-25 attachment point on the engine mount?  I think this might be a bit of an overkill but would like to ask others if they are running this short cable.

_________________
Gary Blankenbiller
RV10 - # 40674
(N2GB Flying)

Deems Davis

Joined: 09 Jan 2006
Posts: 925

Posted: Tue Mar 18, 2008 12:24 pm Post subject: Neg Battery Cable Routing

Gary, Part of your question has come up before, (probably on the 

aeroelectric-list. It was specifically addressed  to Bob Nuckolls  at 

one of his Aero Electric seminars. For aircraft like the RV-10 where the 

standard battery mount position is in the rear of the aircraft. Bob saw 

no problems in grounding the batteries  locally (i.e. to the airframe at 

the battery location) and avoiding the weight, expense and complexity of 

running the additional heavy cable forward to the common firewall ground.



Deems Davis # 406

'Its all done....Its just not put together'

http://deemsrv10.com/



orchidman wrote:

 	  Quote: 	
		   



 I am trying to wrap up the design of the Negative battery lead from the battery to the starter.  I have two specific questions.



 >From the Neg terminal of the battery, Vans shows that you go to airframe ground at the battery mount frame and that is all.  Others have a Neg cable paralleling the Pos cable to the firewall where the Neg lead is grounded to the firewall.  I am considering grounding at the battery mount frame and continuing the cable forward to the firewall.  My first question is, how many are running 2 cables and if so, are you grounding at both locations?  I ask this because in theory it is creating a ground loop.

orchidman

Joined: 10 Jul 2006
Posts: 277
Location: Oklahoma City - KRCE

Posted: Tue Mar 18, 2008 12:38 pm Post subject: Re: Neg Battery Cable Routing

 	  Deems Davis wrote: 	
		  ...For aircraft like the RV-10 where the 

standard battery mount position is in the rear of the aircraft. Bob saw 

no problems in grounding the batteries  locally (i.e. to the airframe at 

the battery location) and avoiding the weight, expense and complexity of 

running the additional heavy cable forward to the common firewall ground. 	


Bob is located only about 2 1/2 hours away but I have never attended his seminar.  I have his books.

I know there are people flying that have done both and I am trying to see which might be better and any problems some might have had with either approach.

Are there any advantages or needs to having a Neg cable going to the firewall in the -10?

_________________
Gary Blankenbiller
RV10 - # 40674
(N2GB Flying)

LarryRosen

Joined: 16 Jan 2006
Posts: 415
Location: Medford, NJ

Posted: Wed Mar 19, 2008 10:24 am Post subject: Neg Battery Cable Routing

The advantage to running the ground cable forward is that it will 

eliminate ground loops and it gives a efficient path from the starter 

ground back to the battery.

The negatives are well stated by Deems.

I would like some feed back from those that have grounded the battery 

locally.  How is it working?  Are you having any issues with ground loops?

Larry Rosen

#356

orchidman wrote:

 	  Quote: 	

 Deems Davis wrote:

> ...For aircraft like the RV-10 where the 

> standard battery mount position is in the rear of the aircraft. Bob saw 

> no problems in grounding the batteries  locally (i.e. to the airframe at 

> the battery location) and avoiding the weight, expense and complexity of 

> running the additional heavy cable forward to the common firewall ground.

>     

 Bob is located only about 2 1/2 hours away but I have never attended his seminar.  I have his books.

 I know there are people flying that have done both and I am trying to see which might be better and any problems some might have had with either approach.

 Are there any advantages or needs to having a Neg cable going to the firewall in the -10?

 --------

 Gary Blankenbiller

 RV10 - # 40674

 Fuselage SB

 (N410GB reserved)

 Read this topic online here:

 http://forums.matronics.com/viewtopic.php?p=170739#170739

_________________
Larry Rosen
#40356
N205EN (reserved)
<http>

msausen

Joined: 25 Oct 2007
Posts: 559
Location: Appleton, WI USA

Posted: Wed Mar 19, 2008 11:35 am Post subject: Neg Battery Cable Routing

For me the decision was fairly easy.  Big engine, lot's of cold weather time.  Any advantage to cold starting is welcomed for me.  If I still lived in Texas I probably wouldn't worry much about grounding back at the battery mount.  I'll be through bolting the neg cable at the firewall and using that point as the airframe ground and the point for all the avionics up front.  I'm also using #2 welding cable all the way to the starter.  Might be overkill but I'll never have to worry about if the cable from the battery to the starter is the problem when it won't turn over.



Michael



--

dlm46007(at)cox.net
Guest

Posted: Wed Mar 19, 2008 3:39 pm Post subject: Neg Battery Cable Routing

Have you considered two Odyssey batteries in parallel with two masters? My

setup can dump both batteries into the starter 1200A+ to start and 500a for

a minute or so.

--

orchidman

Joined: 10 Jul 2006
Posts: 277
Location: Oklahoma City - KRCE

Posted: Thu Mar 20, 2008 3:29 am Post subject: Re: Neg Battery Cable Routing

 	  dlm46007(at)cox.net wrote: 	
		  Have you considered two Odyssey batteries in parallel with two masters? My

setup can dump both batteries into the starter 1200A+ to start and 500a for a minute or so. -- 	


I plan on Van's battery and Tim's Aux/Esen batteries.  After the appreciated comments here and talking to Stein, it looks like I will be going straight from the battery to the firewall where I will single point 'ground' both sets of batteries to the plane and from there to everything else.

_________________
Gary Blankenbiller
RV10 - # 40674
(N2GB Flying)

msausen

Joined: 25 Oct 2007
Posts: 559
Location: Appleton, WI USA

Posted: Thu Mar 20, 2008 5:24 am Post subject: Neg Battery Cable Routing

Yep, also something I'm doing and another reason for using #2.  



Michael



--

msausen

Joined: 25 Oct 2007
Posts: 559
Location: Appleton, WI USA

Posted: Thu Mar 20, 2008 5:32 am Post subject: Neg Battery Cable Routing

While it is probably way overkill I'm still considering adding a third battery, similar to Tim's method, that can supply the dual lightspeeds regardless of the state of the two main batteries.  The two main batteries will be controlled via two masters but the backup battery would be only wired to the Lightspeeds.



Basically it is the standard configuration for dual lightspeeds.  I'm essentially treating the two main batteries as one big one rather than adding the complexity of a split buss or a single big battery.  But I haven't made my final decisions on the busing yet.



Michael



--

pitts_pilot(at)bellsouth.
Guest

Posted: Thu Mar 20, 2008 8:00 am Post subject: Neg Battery Cable Routing

RV Builder (Michael Sausen) wrote:

  	  Quote: 	
		      	  Quote: 	
		  --> RV10-List message posted by: "RV Builder (Michael Sausen)" <rvbuilder(at)sausen.net> (rvbuilder(at)sausen.net)



While it is probably way overkill I'm still considering adding a third battery, similar to Tim's method, that can supply the dual lightspeeds regardless of the state of the two main batteries.  The two main batteries will be controlled via two masters but the backup battery would be only wired to the Lightspeeds. 	
 	
 My two pennies here.  YMMV!  Two batteries really complicates things, and three surely puts it over the top.  I know, and i do understand your concern.  However, bear in mind that all the batteries need to be recharged automatically .... with no intervention by anyone.  No switches to throw ...... nothing to manage the batteries electrical health ..... because when you forget, and circumstances force you to need that backup ..... it won't be there.

  	  Quote: 	
		      	  Quote: 	
		  Basically it is the standard configuration for dual lightspeeds.  I'm essentially treating the two main batteries as one big one rather than adding the complexity of a split buss or a single big battery.  But I haven't made my final decisions on the busing yet. 	
 	
 I don't plan on including alternative ignition in my -10.  My experience in all these many years of magneto ignition has been really good ..... only two failures (one caused by me   ) in over 2500 hours, and failing one mag was a non-event.  I'm not impressed with KISS as a rock group, but as a systems mantra, I can't seem to ignore it.

 

 I will have an 'essential buss' ...... but it will be powered by the one battery  in my electrical system.  The EB will only be there to allow me to shed unnecessary load quickly.

 

 Gary (down below) wants to be able to supply humongous starter current.  A good idea, I guess, but the added weight and systems to support even the second battery goes against my KISS principle ...... and if you truly take care of your single battery you really don't need to have a second one.  They do give you warning of impending diminished operation if you care to look.  If you leave something on and run your battery down, it's really nice to go 'oh s**t' and employ your backup battery (if it's charged!) and use it to start and fo fly.  With dual electronic ignition, I'd surely have a second battery to power the ignition ...... which will work as long as the problem is a dead primary battery and not a wiring failure or solenoid failure or ..... well, the list goes on when trying to create a truly redundant system.

 

 Sorry for the rant, but I've known of at least one failure of the 'backup' system when it was needed for flight ...... and I don't want to experience that first hand.  For me, the benefits do not outweigh the risks.  For the rest of you, I hope you really give your systems designs careful thought and 'what if' it to death.

 Linn ..... plodding along.

 do not archive

 [quote]   [quote]  Michael  --

Tim Olson

Joined: 25 Jan 2007
Posts: 2881

Posted: Thu Mar 20, 2008 8:25 am Post subject: Neg Battery Cable Routing

Sorry Linn, but the EFIS world really changes the paradigm a bit

on what usefulness a 2nd battery can be.  Most EFIS systems

won't stay running while you crank an engine, and most EFIS

systems take a little time to come up to provide datalink

weather and other services, and to just do thorough self-tests

and the normal routine boot process.  You can shortcut the

boot, but it's at the expense of self-tests and sensor

accuracies.  Having a 2nd battery there to get things running

pre-start, so you have a display of all engine parameters,

and everything else, is a great thing.  No, it's not a 100%

necessary thing, but it is a whole different situation than

the panels common 5 or more years ago.  The electronic ignition

adds one more place to use a 2nd battery...but in my install

I combined the function and just have 2....I didn't go to

3.  2 though, that will be very common with EFIS based installs.

Tim Olson - RV-10 N104CD - Flying

do not archive

linn Walters wrote:

 	  Quote: 	
		   RV Builder (Michael Sausen) wrote:

> 

>

> While it is probably way overkill I'm still considering adding a third battery, similar to Tim's method, that can supply the dual lightspeeds regardless of the state of the two main batteries.  The two main batteries will be controlled via two masters but the backup battery would be only wired to the Lightspeeds.

 My two pennies here.  YMMV!  Two batteries really complicates things, 

 and three surely puts it over the top.  I know, and i do understand your 

 concern.  However, bear in mind that all the batteries need to be 

 recharged automatically .... with no intervention by anyone.  No 

 switches to throw ...... nothing to manage the batteries electrical 

 health ..... because when you forget, and circumstances force you to 

 need that backup ..... it won't be there.

> Basically it is the standard configuration for dual lightspeeds.  I'm essentially treating the two main batteries as one big one rather than adding the complexity of a split buss or a single big battery.  But I haven't made my final decisions on the busing yet.

 I don't plan on including alternative ignition in my -10.  My experience 

 in all these many years of magneto ignition has been really good ..... 

 only two failures (one caused by me  ) in over 2500 hours, and 

 failing one mag was a non-event.  I'm not impressed with KISS as a rock 

 group, but as a systems mantra, I can't seem to ignore it.

 I will have an 'essential buss' ...... but it will be powered by the one 

 battery  in my electrical system.  The EB will only be there to allow me 

 to shed unnecessary load quickly.

 Gary (down below) wants to be able to supply humongous starter current.  

 A good idea, I guess, but the added weight and systems to support even 

 the second battery goes against my KISS principle ...... and if you 

 truly take care of your single battery you really don't need to have a 

 second one.  They do give you warning of impending diminished operation 

 if you care to look.  If you leave something on and run your battery 

 down, it's really nice to go 'oh s**t' and employ your backup battery 

 (if it's charged!) and use it to start and fo fly.  With dual electronic 

 ignition, I'd surely have a second battery to power the ignition ...... 

 which will work as long as the problem is a dead primary battery and not 

 a wiring failure or solenoid failure or ..... well, the list goes on 

 when trying to create a truly redundant system.

 Sorry for the rant, but I've known of at least one failure of the 

 'backup' system when it was needed for flight ...... and I don't want to 

 experience that first hand.  For me, the benefits do not outweigh the 

 risks.  For the rest of you, I hope you really give your systems designs 

 careful thought and 'what if' it to death.

 Linn ..... plodding along.

 do not archive

>

> Michael

msausen

Joined: 25 Oct 2007
Posts: 559
Location: Appleton, WI USA

Posted: Thu Mar 20, 2008 10:18 am Post subject: Neg Battery Cable Routing

I’ll be doing an e-bus, probably via the VP-200.  I should have mentioned that the dedicated battery for alt power to the Lightspeeds would be connected to the main bus for recharging via a diode.  My dual batteries are a pair of PC-680’s whereas normally an equivalent single battery would be something like a PC-925.  Little more weight  but also a little more power and a level of redundancy I feel is needed for an electrically dependant engine and under normal circumstances either main battery should be able to start the engine.  Not the best choice for everyone by any means.  

   

  I really don’t see your comments as a rant at all.  They are simply another point of view that adds data points to a conversation.  Each person needs to evaluate the needs of their specific setup, in conjunction with their mission profile (you have one right?) and do whatever is necessary so they can sleep well at night.  Once I do figure out the detail on my electrical system, I plan on posting it here and over on the Aerolectric list to be poked at.  J  

   

Michael  

       

From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of linn Walters

 Sent: Thursday, March 20, 2008 11:58 AM

 To: rv10-list(at)matronics.com

 Subject: Re: Re: Neg Battery Cable Routing  

  

  

   

RV Builder (Michael Sausen) wrote:

 

    	  Quote: 	
		  --> RV10-List message posted by: "RV Builder (Michael Sausen)" <rvbuilder(at)sausen.net> While it is probably way overkill I'm still considering adding a third battery, similar to Tim's method, that can supply the dual lightspeeds regardless of the state of the two main batteries.  The two main batteries will be controlled via two masters but the backup battery would be only wired to the Lightspeeds. 	
  

My two pennies here.  YMMV!  Two batteries really complicates things, and three surely puts it over the top.  I know, and i do understand your concern.  However, bear in mind that all the batteries need to be recharged automatically .... with no intervention by anyone.  No switches to throw ...... nothing to manage the batteries electrical health .... because when you forget, and circumstances force you to need that backup .... it won't be there.

 

    	  Quote: 	
		  Basically it is the standard configuration for dual lightspeeds.  I'm essentially treating the two main batteries as one big one rather than adding the complexity of a split buss or a single big battery.  But I haven't made my final decisions on the busing yet. 	
  

I don't plan on including alternative ignition in my -10.  My experience in all these many years of magneto ignition has been really good .... only two failures (one caused by me  ) in over 2500 hours, and failing one mag was a non-event.  I'm not impressed with KISS as a rock group, but as a systems mantra, I can't seem to ignore it.

 

 I will have an 'essential buss' ...... but it will be powered by the one battery  in my electrical system.  The EB will only be there to allow me to shed unnecessary load quickly.

 

 Gary (down below) wants to be able to supply humongous starter current.  A good idea, I guess, but the added weight and systems to support even the second battery goes against my KISS principle ...... and if you truly take care of your single battery you really don't need to have a second one.  They do give you warning of impending diminished operation if you care to look.  If you leave something on and run your battery down, it's really nice to go 'oh s**t' and employ your backup battery (if it's charged!) and use it to start and fo fly.  With dual electronic ignition, I'd surely have a second battery to power the ignition ...... which will work as long as the problem is a dead primary battery and not a wiring failure or solenoid failure or ..... well, the list goes on when trying to create a truly redundant system.

 

 Sorry for the rant, but I've known of at least one failure of the 'backup' system when it was needed for flight ...... and I don't want to experience that first hand.  For me, the benefits do not outweigh the risks.  For the rest of you, I hope you really give your systems designs careful thought and 'what if' it to death.

 Linn ..... plodding along.

 do not archive

 

   [quote]  Michael --

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