Matronics Email Lists :: View topic

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

SD8 alt connection

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

gonzo24

Joined: 26 Oct 2010
Posts: 3

Posted: Thu Oct 28, 2010 3:12 pm Post subject: SD8 alt connection

sorry if this has been covered but I cannot find it.



I am needing info on connection of the SD-8 aux alternator.  I have a B&C 60 amp primary and one odyssey 680 batt.  Z13 shows the SD-8 connection from the relay to the batt contactor I believe.



can I just hook this power out relay lead direct to the batt buss for back up power only?  Do i use a fusible link or in line fuse holder or breaker for this connection?



I'm running dual lightspeed plasma II plus' as well.  



Is their a diagram showing how to properly set up this mix of components?



thanks guys...

_________________
RV-7a completed flown 700+ hrs sold
Rv-7 under construction

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Oct 28, 2010 7:40 pm Post subject: SD8 alt connection

At 06:12 PM 10/28/2010, you wrote:




sorry if this has been covered but I cannot find it.



I am needing info on connection of the SD-8 aux alternator.  I have a 

B&C 60 amp primary and one odyssey 680 batt.  Z13 shows the SD-8 

connection from the relay to the batt contactor I believe.



can I just hook this power out relay lead direct to the batt buss for 

back up power only?  Do i use a fusible link or in line fuse holder 

or breaker for this connection?



I'm running dual lightspeed plasma II plus' as well.



Is their a diagram showing how to properly set up this mix of components?



    Yes, it's Z-13/8. When the SD-8 is powered up,

    the battery contactor can optionally be turned

    off and the SD-8 used to power only items driven

    from the battery bus.



    Bob . . .

gonzo24

Joined: 26 Oct 2010
Posts: 3

Posted: Fri Nov 19, 2010 6:03 am Post subject: Re: SD8 alt connection

Bob,



thank you for the reply.  In reviewing the Z-13/8 schematic... since the 2awg batt and 14awg batt buss are all connecting at the same point on the batt contactor on the engine side of the firewall....  Wouldn't it be the same thing to terminate the SD-8 output lead directly to the battery buss stud inside the cabin?



I ask this as all of my SD-8 power components i.e. regulator, capacitor, OV, relay are installed cabin side of the firewall (per the instructions received with these parts).  Why would it be necessary to run the lead with the inline 30amp fuse back out to the batt contactor?  In the event of a Primary alt failure, the SD-8 should still be excited through the 14AWG contact it has to the primary battery.



Should one connect a smaller aux batt on the Batt buss as well in this case?  I ask this as LSE's power diagram shows two batteris for dual ignition as well.  



thank you for your time.

_________________
RV-7a completed flown 700+ hrs sold
Rv-7 under construction

nuckolls.bob(at)aeroelect
Guest

Posted: Fri Nov 19, 2010 1:05 pm Post subject: SD8 alt connection

At 08:03 AM 11/19/2010, you wrote:

 	  Quote: 	
		  



Bob,



thank you for the reply.  In reviewing the Z-13/8 schematic... since 

the 2awg batt and 14awg batt buss are all connecting at the same 

point on the batt contactor on the engine side of the 

firewall....  Wouldn't it be the same thing to terminate the SD-8 

output lead directly to the battery buss stud inside the cabin?


	


   Whoops! You have an always hot fat wire coming through

   the firewall?



 	  Quote: 	
		  I ask this as all of my SD-8 power components i.e. regulator, 

capacitor, OV, relay are installed cabin side of the firewall (per 

the instructions received with these parts).  Why would it be 

necessary to run the lead with the inline 30amp fuse back out to the 

batt contactor?  In the event of a Primary alt failure, the SD-8 

should still be excited through the 14AWG contact it has to the 

primary battery.


	


   Okay, you've arranged components with priorities ordered

   differently than suggested in the Z-figures and I understand

   why. I wish B&C wouldn't put those little notes in with

   his products suggesting that certain electro-whizzies are better

   off inside the cabin.



   Sure, connect the SD-8 to the battery bus . . . in fact,

   put a 30A fuse in one of the battery bus fuse-slots and

   use it to route power to the system.



   Airplane parts are airplane parts. They are selected and

   qualified for specific duty in locations selected first

   for functionality, minimum parts count, weight, and nice

   failure mode effects analysis. Obviously, boxes with LCD

   displays, push buttons and knobs NEED to go in the cabin

   and their tolerance for environmental extremes are relaxed

   because shares spaces where people sit. All other gizmos,

   particularly system power management parts should be happy

   living anywhere except perhaps bolted to an exhaust stack.



   The current locations for your SD-8 system parts

   and battery bus are now pretty much a given so you're

   compelled to make adjustments for how the wires are

   handled.



 	  Quote: 	
		  Should one connect a smaller aux batt on the Batt buss as well in 

this case?  I ask this as LSE's power diagram shows two batteris for 

dual ignition as well.


	


    No . . . don't mix-match architectures. I've

    encountered several instances where the system

    integrator attempted to cherry-pick what appeared

    to be "good and wonderful" features of multiple

    systems with the notion that each plucking of

    an idea makes the whole more righteous.



    The whole idea behind LSE's recommendations go

    to increasing probability that at least one

    of two ignition systems will have power irrespective

    of MULTIPLE failures . . . and without regard to

    the thought processes that ago toward fabrication

    of a FAILURE TOLERANT system.



    The battery in the OBAM aircraft owned, operated

    and maintained by a cognizant builder is the most

    reliable source of energy in the airplane. It's

    only limitation is total stored energy traded off

    with how much lead, water and plastic the builder

    is willing to drag around. Then comes TWO, engine

    driven power sources capable of mitigating battery

    limitations. By the way, if you DO find yourself

    operating either battery only . . . or battery+SD8,

    then turn one of the ignition systems off. The

    engine will hardly know the difference and your

    electrical system loads drop by about 2 amps.



    B&C and LSE make recommendations based on their

    best wishes and understanding of the systems they

    sell. The AeroElecric Connection goes toward a

    rational approach for crafting the whole system

    based on ingredients that go into recipes for

    success going WWWwaaayyyy back . . . further

    than any current supplier of electro-whizzies.



    Understand that supplier recommendations are

    almost never 'wrong'. But most suppliers are

    not system integrators with a focus on the big

    picture. Note how many different Z-figures there

    are as opposed to how many ways the legacy T/C

    aircraft is wired . . .



    I'll have a first-hand review of a dark-n-stormy

    night story to share with the List where the

    outcome wasn't a complete disaster . . . everybody

    walked away. The system integrator cherry-picked

    whippy ideas without regard their 'fit' in the

    overall system. The effects of some poor decisions

    were expensive and linger to this day. I'll tell

    you all about it after the court case settles.



    Please don't take anything above as a

    harbinger of doom for what you've described.

    Your system's WIRING and FUNCTIONALITY are

    going to be just fine and will function as

    advertised. We're only sifting through the

    simple-ideas that go to very low orders of

    risk.

 	  Quote: 	
		  thank you for your time.


	




    You're most welcome. That's what we're all here

    for . . .



   Bob . . .

user9253

Joined: 28 Mar 2008
Posts: 1925
Location: Riley TWP Michigan

Posted: Sat Nov 20, 2010 7:41 am Post subject: Re: SD8 alt connection

Most electrical devices that can not be shut off should be on the engine side of the firewall.  And if practical, devices that can be shut off should also be on the engine side of the firewall.  Look at each component of the electrical system and ask yourself, "If this device starts smoking, would I rather have it inside of the cockpit or outside, and how will I shut it off?"  When something starts smoking inside of the cockpit, it will be difficult to know what device it is.  Shutting off the master switch should remove power from almost everything inside of the cockpit.

It would be better to place the following components on the engine side of the firewall: Battery, Battery Contactor, Main Battery Bus, Essential Bus Relay, Voltage Regulator, Capacitor, Alternator Relay

Joe

_________________
Joe Gores

slipstream(at)wavecable.c
Guest

Posted: Sun Nov 21, 2010 10:12 am Post subject: SD8 alt connection

Sure wish I'd read this a year or more ago.  As Gonzo wrote above, I followed the installation diagrams on the SD-8 and LR-3C to place a number of devices on the pilot side of the firewall.  This includes the SD-8's voltage regulator, relay, capacitor, and crowbar OV module.  On the main side of the system, the LR-3 is also mounted on the pilot side of the firewall.  The hot battery bus, E-bus relay, current limiters, shunts, inline fuses and fuselinks are in the engine bay.  Moving everything to the engine side would be a major hassle of working around the engine mount and plumbing (I'd probably just remove the whole engine and mount assembly), but less of a hassle now than after it's flying, I suppose.

  

 So, considering the devices above, what's my risk? Is it worth pulling the motor off to consolidate all my electrical devices, or can I sleep at night knowing that the items I do have inside the cabin are negligible risk?  For reference, my electrical system follows Z-13/8 precisely, except for the B&C LR-3 voltage regulator and no electronic ignition. 

   

 Brooks Wolfe

 RV-7 -- Finishing details details

  

 [i]----

user9253

Joined: 28 Mar 2008
Posts: 1925
Location: Riley TWP Michigan

Posted: Sun Nov 21, 2010 2:14 pm Post subject: Re: SD8 alt connection

Brooks,

I would sure hate to pull an engine to modify the electrical system.  Would it be much of a hassle to move the voltage regulator to the engine side and leave the other items in that circuit where they are?  The voltage regulator should have adequate cooling.  B&C must not think that their parts will fail.  My RV-12, that is built according to Van's instructions, has the voltage regulator forward of the firewall, but the capacitor is in the cockpit.

  An option is to add a relay in the engine compartment to shut off the AC output of the dynamo.  Perhaps Bob will comment on the feasibility of doing that.  The dynamo will be putting out a high voltage without a load.

  There is an ideal way of doing things and there is a good-enough way.  I do not know where to draw the line.  Many times I am tempted to take shortcuts.  Then I ask myself what is the best in the long run.

  At least you have the main battery bus forward of the firewall.  That is the most dangerous component.

Joe

_________________
Joe Gores

gonzo24

Joined: 26 Oct 2010
Posts: 3

Posted: Sun Nov 21, 2010 5:58 pm Post subject: Re: SD8 alt connection

Hello Bob,



As usual your answers are thought provoking, specific, and yet posed in such a way to allow for builder interpretation to maintain a fault tolerant architecture.



Just to clarify, I have not routed any "fat" 2awg wires into the cockpit per your written instructions for reduction of electrical noise issues.  The only two power leads coming through the firewall are... The Batt buss which is fed from the + of the battery via a 14 awg wire.  The main buss is fed off of the 60 A limiter fuse from the post opposite the B&C Alternator feed through a short 8 awg lead.  



Thanks again for your thorough and timely response.

_________________
RV-7a completed flown 700+ hrs sold
Rv-7 under construction

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Nov 23, 2010 6:16 am Post subject: SD8 alt connection

At 12:08 PM 11/21/2010, you wrote:

 	  Quote: 	
		  



Sure wish I'd read this a year or more ago.  As Gonzo wrote above, I 

followed the installation diagrams on the SD-8 and LR-3C to place a 

number of devices on the pilot side of the firewall.  This includes 

the SD-8's voltage regulator, relay, capacitor, and crowbar OV 

module.  On the main side of the system, the LR-3 is also mounted on 

the pilot side of the firewall.  The hot battery bus, E-bus relay, 

current limiters, shunts, inline fuses and fuselinks are in the 

engine bay.  Moving everything to the engine side would be a major 

hassle of working around the engine mount and plumbing (I'd probably 

just remove the whole engine and mount assembly), but less of a 

hassle now than after it's flying, I suppose.



So, considering the devices above, what's my risk? Is it worth 

pulling the motor off to consolidate all my electrical devices, or 

can I sleep at night knowing that the items I do have inside the 

cabin are negligible risk?  For reference, my electrical system 

follows Z-13/8 precisely, except for the B&C LR-3 voltage regulator 

and no electronic ignition.


	


    No, don't rip up anything and re-configure. The risks

    are low as most have to do with crash worthiness

    for taking always-hot feeders long distances or through

    firewalls. Just pay attention to support and insulation

    of your always hot conductors.

   Bob . . .

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Nov 23, 2010 6:19 am Post subject: SD8 alt connection

Hello Bob,



As usual your answers are thought provoking, specific, and yet posed 

in such a way to allow for builder interpretation to maintain a fault 

tolerant architecture.



Just to clarify, I have not routed any "fat" 2awg wires into the 

cockpit per your written instructions for reduction of electrical 

noise issues.  The only two power leads coming through the firewall 

are... The Batt buss which is fed from the + of the battery via a 14 

awg wire.  The main buss is fed off of the 60 A limiter fuse from the 

post opposite the B&C Alternator feed through a short 8 awg lead.



Thanks again for your thorough and timely response.



   Sounds good to me but not sure why you

   added a limiter to the bus feeder. As long

   as your firewall pass thru is well crafted,

   that device will never be called upon to

   act for its intended purpose.

   Bob . . .

Display posts from previous:

	Matronics Email Lists Forum Index -> AeroElectric-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum