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Noah

Joined: 02 Jul 2009
Posts: 18
Location: Rhode Island

Posted: Fri Feb 26, 2010 8:50 pm Post subject: Z13/20

I purchased an SD-20 auxiliary alternator after reading AEC a couple of years ago, and had been planning a Z-13/20.  Subsequent to this purchase and installation on my engine, Bob has indicated on numerous occasions that this was not a well thought out architecture, and thus was withdrawn a couple of years ago.



However, I have NEVER seen an explanation of what the concerns were regarding this architecture, and more particularly, what its' failure modes are.



So what say ye, Bob?  What did you decide that you didn't you like about this architecture?  What makes it so objectionable?



A related question regards what is "magic" about the SD-8 that allows it to be used in the Z/13 architecture while the SD-20 has been deemed NOT compatible.



I don't have much experience analyzing schematics but when I look at Z-13/20, I guess I just don't see what the issue is.  Can someone please educate me?



Highest Regards,



Noah Forden

RV-7A

_________________
Highest Regards,

Noah Forden
RV-7A
Rhode Island

nuckolls.bob(at)aeroelect
Guest

Posted: Sat Feb 27, 2010 9:38 pm Post subject: Z13/20

 	  Quote: 	
		  I don't have much experience analyzing schematics but when I look at 

Z-13/20, I guess I just don't see what the issue is.  Can someone 

please educate me?


	


    It's clumsy . . . my associates would

    call it a kluge. Z-12 shows a well considered

    integration of the SD20 into a legacy system

    with an e-bus added. I'm working on a drawing

    that explores another approach to tying the

    SD-20 and a main alternator onto two batteries.

    Build a 13/20 if you wish. It will function as

    advertised. I pulled the drawing because I'm

    not proud of it and I'd prefer not to be associated

    with the system when and if it is used.



    Bob . . .

flagstone(at)cox.net
Guest

Posted: Sun Feb 28, 2010 6:04 pm Post subject: Z13/20

Bob:

  

 Is it going to have 2 LR-3's or an LR-3/SB-1  combination?  What's the timeframe before we get a peek?

  

 Thanks

  

 Mark

 [quote]   ---

Noah

Joined: 02 Jul 2009
Posts: 18
Location: Rhode Island

Posted: Sun Feb 28, 2010 7:36 pm Post subject: Re: Z13/20

Bob, I appreciate the response, but from a technical perspective, it doesn't give me much to go on.



Let me try my question from a different angle.  



I prefer Z-13 over Z-12 because of the salient advantages it offers, namely that it is a two-layered electrical system, with (as far as I can tell), very little single point failure potential.  With the aux alternator feeding the battery directly, the main contactor is removed from the list of single point failure modes requiring landing and fixing/replacing  something.  Additionally, a contactor failure does not take BOTH alternators essentially offline, as occurs with Z12.  I believe that you yourself have said on numerous occasions that Z13 is your architecture of choice.  



When I take a 6000 mile trip, I don't want a main contactor failure to mean I am on the ground for an hour, a day, or a week waiting for a replacement.  My mission requires that I be able to fly a couple of thousand miles home, COMFORTABLY, to replace that single failed electrical component in the comfort of my own hangar.  Unless I am mistaken somehow, Z13 allows this, and Z12 does not.



So the question I will ask again is,  what is it about the SD-20 which makes it not compatible with Z-13, while the SD-8 IS compatible?  



Is it because the SD-8 is a dynamo, and needs no flash from the bus?  Is it because the lower current SD-8 driven E-bus can use a backfeed switch instead of a relay?  Something else?



I have searched the archives extensively on this topic and have never found a direct technical response to this question, despite many builders who have asked the question in one way or another, and who require a Z-13 architecture with an up-sized auxiliary alternator and E-Bus, so that they can FLY COMFORTABLY all the way home, not just to the next airport within an hours range where they will have to sit for a day or two.



Z14 doesn't interest me because in my case its complexity isn't needed - all of my critical flight instruments and nav gear have internal battery backups and the additional weight and complexity is overkill IMHO.

_________________
Highest Regards,

Noah Forden
RV-7A
Rhode Island

longg(at)pjm.com
Guest

Posted: Mon Mar 01, 2010 7:41 am Post subject: Z13/20

Noah,



You're trying to fit a square peg in a round hole? If you're mission is

complete and redundant reliability while flying over the generally

abandoned Kansas Territory, you've got the wrong approach.



Z-13/8 is designed for emergency redundancy and yes the lower power

SD-8. This should be read as minimum required equipment to facilitate

landing at the nearest facility (the tiny spare tire in the back of your

car has the same design goal - pretty simple eh?). Z-13 was not intended

as an all out fully redundant Rambo system, nor is it designed to

sustain the output provided by the SD-20. 



Truth is, if you have the right equipment in your panel you can fly long

past the Kansas Territory running with the SD-8. I can do the same and I

am flying all electric. It doesn't get more desperate than that.



If you don't have the stomach to build out a Z-12 or Z-14 (closer to

what you want), than buy the twenty dollar contactor and throw it in the

glove box with the spare batteries.



Glenn



--

andrewbutler(at)ireland.c
Guest

Posted: Mon Mar 01, 2010 8:54 am Post subject: Z13/20

Hi Noah,



I'm no expert and my bird is a couple of months away from fire up, but my panel and all electrics are finished and appear to work. Mine is based on the Z13/8 architecture.



The architecture is a template not a solution. My understanding is that the wares being offered by the "owners" of this forum are design and engineering oriented rather than solution oriented, hence the feeling that it is difficult to get a straight answer when you ask a solution oriented question. A lot of time, effort and experience has gone into fine tuning the aeroelectric templates. Even so, there is nothing wrong with putting a SD-20 in place of the SD-8. However, by changing one of the major components of a design template, you completely change the profile of the architecture and the original design goals are no longer a match (more weight, more expense etc.) and it is invalidated.



So if the design goal is to get down safe in the event of an alt failure for the least weight and cost penalty, even if you are more than an hour from the nearest airport, then the design that fits the bill is the Z13/8. If you want an alt failure to be a normal mode of operation, then it is the design that you deploy has to change, rather than the template you start with.



Andrew Butler

RV7 EI-EEO

Galway, Ireland.

---

rckol

Joined: 14 Nov 2008
Posts: 36

Posted: Mon Mar 01, 2010 10:49 am Post subject: Re: Z13/20

Noah,



In another thread earlier this weekend I proposed the use of a second, parallel master contactor in Z-12 instead of an E-bus to accomplish what you are looking for.  This would give you the potential to fully recover from a contactor failing open in flight and still be set up to run off the battery through an alternate path if need be.



You might use contactors with low holding current, like an EV-200, or a standard contactor with the gizmo Bob is working on to reduce the holding current for Plan C (battery only ops)



Dick Kaehler

_________________
rck

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Mar 01, 2010 4:10 pm Post subject: Z13/20

 	  Quote: 	
		  In another thread earlier this weekend I proposed the use of a 

second, parallel master contactor in Z-12 instead of an E-bus to 

accomplish what you are looking for.  This would give you the 

potential to fully recover from a contactor failing open in flight 

and still be set up to run off the battery through an alternate path 

if need be.


	


  The e-bus is NOT intended to back up the battery contactor.

  The ENDURANCE bus philosophy supplies TWO independent power

  paths to electro-whizzies considered most useful for maximizing

  a limited energy resource (battery) during alternator failure.

  The idea is to SUSTAIN flight battery only to airport of intended

  destination or at least MUCH longer than the legacy 30 minute

  rule embraced by much of TC aviation.



  Contactors have an energy budget that contributes nothing to

  running a radio or illuminating a map. Hence the idealized

  response to a low-volts warning of shutting down all non-productive

  pieces of hardware INCLUDING battery contactors until comforable

  arrival with the earth is assured.



  The alternate feedpath just happens to BACK up the contactor

  but the purpose of the alternate feedpath is to enable sustained,

  comfortable operations WITHOUT a contactor. So, if you can

  demonstrably do without the contactor under one set of conditions

  (loss of alternator) why carry the weight around just to back

  it up in the rare event that it fails?



  Bob  . . .

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Mar 01, 2010 4:29 pm Post subject: Z13/20

 	  Quote: 	
		  Z-13/8 is designed for emergency redundancy and yes the lower power

 SD-8. This should be read as minimum required equipment to facilitate

 landing at the nearest facility (the tiny spare tire in the back of your

 car has the same design goal - pretty simple eh?). Z-13 was not intended

 as an all out fully redundant Rambo system, nor is it designed to

 sustain the output provided by the SD-20. 	


   Actually, when the endurance-bus was first crafted in a LongEz

   about 20 years ago, it was Figure Z1 (ancestor to Z-11) and

   the idea was to be able to operate battery only for duration

   of fuel aboard.



   In other words, craft a Plan-B that used preventative maintenance

   of a battery that insured its ability to power a minimal list

   of goodies that could keep you on-track for perhaps hours.



   As electrically dependent airplanes came along, endurance mode

   loads went up which increased the size of batteries to support

   it. At the same time, vacuum pumps were falling into disfavor

   so the opportunity to support endurance mode loads with an 8A

   enhancement was attractive, hence Z-13/8. Even better yet, if

   endurance loads could be kept at or below 8A, this held the

   battery's entire energy content in reserve for running more

   electro-whizzies during approach to landing and without warning

   the tower that "my airplane might go dark" during the landing

   phase.

  



  	  Quote: 	
		  Truth is, if you have the right equipment in your panel you can fly long

 past the Kansas Territory running with the SD-8. I can do the same and I

 am flying all electric. It doesn't get more desperate than that. 	


   Exactly. In the sum total of all OBAM aircraft under

   construction, there are VERY few that cannot sustain

   flight on an 8A endurance budget. It only requires that

   the builder/operator be willing to put some judicious

   thought into what electro-whizzies are really all that

   helpful in the task of conserving electrical energy.



 

  	  Quote: 	
		  If you don't have the stomach to build out a Z-12 or Z-14 (closer to

 what you want), than buy the twenty dollar contactor and throw it in the

 glove box with the spare batteries. 	


   Contactor failures are rare. Contactors ARE light (under 1#)

   and depending on creativity of the installer, can be changed

   out with a minimum off tools. I've had a number of builders

   state that they intended to carry spares into the Canadian

   north country. That isn't the ONLY equipment they carry as

   a hedge against small precipitating disasters.



   Our FMEA studies on electrical systems is no different

   than the FEMA studies that bush pilots have been doing

   on the total flight system for nearly 100 years. You trade

   off empty weight for features that offset potential failures.

   The real task is to not allow imagined or low risks to

   drive the task into overkill . . .



 [img]cid:.0[/img] 



   Bob . . .

1628a61e.jpg

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tim2542(at)sbcglobal.net
Guest

Posted: Mon Mar 01, 2010 5:54 pm Post subject: Z13/20

 	  Quote: 	
		    Contactors have an energy budget that contributes nothing to

  running a radio or illuminating a map. Hence the idealized

  response to a low-volts warning of shutting down all non-productive

  pieces of hardware INCLUDING battery contactors until comforable

  arrival with the earth is assured.



  The alternate feedpath just happens to BACK up the contactor

  but the purpose of the alternate feedpath is to enable sustained,

  comfortable operations WITHOUT a contactor. So, if you can

  demonstrably do without the contactor under one set of conditions

  (loss of alternator) why carry the weight around just to back

  it up in the rare event that it fails?



  Bob  . . .



Hi Bob.  I'm glad this came up. In the Z10-8 I'm considering, wouldn't a 
	


switch be more efficient than a relay for the E bus load, assuming a ~10 

amp load? (I'm not refering to the brown out relay which I see is 

necessary).

What do these little Bosch type cube relays draw?

Thanks, Tim Andres

Noah

Joined: 02 Jul 2009
Posts: 18
Location: Rhode Island

Posted: Mon Mar 01, 2010 7:51 pm Post subject: Re: Z13/20

[quote="nuckolls.bob(at)aeroelect"] 	  Quote: 	
		  

   ...the opportunity to support endurance mode loads with an 8A

   enhancement was attractive, hence Z-13/8. Even better yet, if

   endurance loads could be kept at or below 8A, this held the

   battery's entire energy content in reserve... 	
  



The beauty of Z-13/8, is that the endurance bus is really NOT an endurance bus, as described above, where your range is limited to battery capacity only.  Z-13/8 should really be called an UNLIMITED ENDURANCE bus because you can fly with any single component failure (excepting battery) for MONTHS.  It is not limited to battery capacity at all, as are Z11 & Z-12.  No getting stranded with Z-13/8. Agreed?



But my technical question remains unanswered.  Why does the SD-8 work in this architecture, while the SD-20 somehow falls apart?



Why changing the capacity of either bus should FORCE a change in overall system architecture is something that makes no sense to me, and thus far, nobody has been willing or able to explain.  This is a PURELY technical question, and requires a PURELY technical explanation.

   

[quote="nuckolls.bob(at)aeroelect"] 	  Quote: 	
		   In the sum total of all OBAM aircraft under construction, there are VERY few that cannot sustain flight on an 8A endurance budget. It only requires that the builder/operator be willing to put some judicious thought into what electro-whizzies are really all that helpful in the task of conserving electrical energy. 	




This misses the point entirely. Rather than trying to convince people that they are wrong for wanting an UNLIMITED ENDURANCE bus with more capacity than 8 amps, why not explain why a 20 amp UNLIMITED ENDURANCE bus powered by an SD-20 is, somehow, not workable?



I'll say it again, the Z-13 is an elegant architecture.  How does upsizing it  force this architecture to fall flat on its face?

_________________
Highest Regards,

Noah Forden
RV-7A
Rhode Island

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Mar 01, 2010 9:08 pm Post subject: Z13/20

 	  Quote: 	
		  

This misses the point entirely. Rather than trying to convince 

people that they are wrong for wanting an UNLIMITED ENDURANCE bus 

with more capacity than 8 amps, why not explain why a 20 amp 

UNLIMITED ENDURANCE bus powered by an SD-20 is, somehow, not workable?



I'll say it again, the Z-13 is an elegant architecture.  How does 

upsizing it  force this architecture to fall flat on its face?


	


   Z-13/20 would function as advertised. It doesn't fall on

   its face . . . it's just not an elegant solution by my

   personal judgment . . . I just didn't want to leave

   it hanging out there with my name on it.



   The SD-8 is a most adequate adjunct to expanding the

   horizons on Z-11 in the endurance mode. The SD-20

   is a keep-it-all running size of alternator that

   encourages the e-bus to become stacked up with lots

   more hardware. I think I like the way Z-8 is

   coming together. It will accommodate two wound-field

   alternators of any combination while supporting a pair

   of batteries (with always hot busses) supported by

   the two alternators totally independent of the main bus.



   The FMEA is looking like the e-bus would go away

   completely and the switching gets simpler.



   Bob . . .

Noah

Joined: 02 Jul 2009
Posts: 18
Location: Rhode Island

Posted: Tue Mar 02, 2010 9:00 am Post subject: Re: Z13/20

When I have heard the term “kluge”, I have taken it to be a catch-all word for the fact that a design has one or more less than desirable characteristics, or failure modes, or performance inhibitors.  Additionally, I take the term “kluge” to mean that a design can be significantly simplified and still perform the same function.  Merriam Webster defines the term as a system made up of poorly matched components.  



I have repeatedly asked “what are the negative implications, the failure modes, the performance hits” when using a Z-13 architecture (UNLIMITED ENDURANCE given any single point failure) with a 20A aux alternator.  None have been offered, and this most recent response, indicating that “Z-13/20 will function as advertised” seems to tell me that there are none (over and above those found with Z13/.  Do I understand your position correctly?  It this simply a case of personal bias against any endurance bus requiring >8A because you deem it generally unnecessary and a little more costly and a little bit heavier? Just trying to understand your position here.  Another way of saying this: are the FMEA for both the Z-13/8 and Z-13/20 essentially equivalent / identical?  If this is the case I am still baffled by the continued strong position against Z-13/20 to the extent that you have completely disavowed it like a red-headed bastard step-child, pulling it from your website and other publications.



The concept of a (limited) endurance bus is a very good one – certainly significantly better than the typical spam-can fleet.  But isn’t the concept of an UNLIMITED ENDURANCE bus, as afforded by Z-13 in both the 8 and 20-A varieties, significantly better still?  If so, why have you continually steered dozens of builders interested in a Z-13 architecture with a 20A E-bus away from this architecture, to a Z-12, with a LIMITED ENDURANCE bus, or to a Z-14, with significantly greater complexity, cost, and weight – when Z-13 offers SIMPLICITY and UNLIMITED ENDURANCE given any probabilistic single point failure?



I still have an uneasy feeling that I must be missing something, that there must be more to it given your continued and strong position on this, but for the life of me, I don’t know what it is.

_________________
Highest Regards,

Noah Forden
RV-7A
Rhode Island

jonlaury

Joined: 06 Nov 2006
Posts: 336

Posted: Tue Mar 02, 2010 10:33 am Post subject: Re: Z13/20

 	  longg(at)pjm.com wrote: 	
		  Noah,



snip.... Z-13 was not intended

as an all out fully redundant Rambo system, nor is it designed to

sustain the output provided by the SD-20. 

-- 	




Z-13/8 may not be "designed" for the SD-20, but is the additional 12 amps (or in my case, 22a ) going to jeopardize the system function, assuming the appropriate size wire, fuses, etc.? 

I just don't see how a larger alternator makes any difference to the functioning of the system.



John

RV7ASask

Joined: 25 Jan 2006
Posts: 36

Posted: Tue Mar 02, 2010 4:51 pm Post subject: Re: Z13/20

I think my original post on Z12/Z13 may have helped start this thread. As I indicated I have changed to a Z13 with a 20A Aux Alternator. 



Attached is my version of the schematic. There are some details missing of course but this is what the system is built around.



My wiring is almost done but I am open to constructive criticism.



Thanks

David Lamb

RV7A Still wiring.

All Elec Schematic.pdf

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nuckolls.bob(at)aeroelect
Guest

Posted: Tue Mar 02, 2010 7:05 pm Post subject: Z13/20

At 12:33 PM 3/2/2010, you wrote:

 	  Quote: 	

longg(at)pjm.com wrote:

 > Noah,

 >

 > snip.... Z-13 was not intended

 > as an all out fully redundant Rambo system, nor is it designed to

 > sustain the output provided by the SD-20.

 > --

Z-13/8 may not be "designed" for the SD-20, but is the additional 12 

amps (or in my case, 22a ) going to jeopardize the system function, 

assuming the appropriate size wire, fuses, etc.?

I just don't see how a larger alternator makes any difference to the 

functioning of the system.

   And as I said, it will function as advertised. I've

   seen V-6's in VW bugs and they too function as

   advertised. I'm in no way attempting to talk you

   out of doing what ever you wish. I was trying to

   convey the idea that while Z-13/20 was my design

   prompted by some discussions at the time . . . I

   was not proud of it and withdrew it. In my opinion

   it argued with design goals for Z-13/8 as a low

   cost, light weight, simple excursion into all-electric

   aircraft. If you are committed to the notion of running

   an SD-20, then I think there are better ways to do it.

   But, do as you wish with confidence . . . but please

   don't call it Z-13/20. That would suggest the configuration

   is something that I have offered as a elegant recipe

   for success. I wouldn't put a 4-bbl carburetor on

   my Chevy 6-cyl but it no doubt could be made to

   function but with little more risk than the stock

   carb would offer.

   Bob . . .

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Mar 02, 2010 7:56 pm Post subject: Z13/20

Might a switch be more efficient than a relay for the E bus load, assuming a ~10 

 amp load? (I'm not refering to the brown out relay which I see is 

 necessary).

   

   Certainly more efficient since the switch does not

   draw current to keep it closed. But the relay is

   called for when it is functioning as a mini-contactor

   located adjacent to the battery bus. If you can reach

   a switch located there, then you could consider the

   subsitution.

  

 What do these little Bosch type cube relays draw? 

 Thanks, Tim Andres



   About 100 mA depending on manufacturer and some

   other details. These are not big energy hogs.



   Bob . . .

     [quote][b]

rckol

Joined: 14 Nov 2008
Posts: 36

Posted: Tue Mar 02, 2010 8:05 pm Post subject: Re: Z13/20

David,



Regarding your schematic, If you are planning to run a heavily loaded e-bus (yours is fused for 15 amps), I think you are going to want to use the heavy duty e-bus switching with a relay (Z-32).  I think this has been recommended for anything over 7 amps.

_________________
rck

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Mar 02, 2010 9:33 pm Post subject: Z13/20

 	  Quote: 	
		  

I have repeatedly asked “what are the negative 

implications, the failure modes, the performance 

hits” when using a Z-13 architecture 

(UNLIMITED ENDURANCE given any single point failure) with a 20A aux alternator.


	


   Actually, it's not unlimited endurance, you're still going

   to run out of fuel. You just don't have to come down because

   you're out of electrons.



 	  Quote: 	
		     None have been offered, and this most recent 

 response, indicating that “Z-13/20 will 

 function as advertised” seems to tell me that 

 there are none (over and above those found with 

 Z13/.  Do I understand your position correctly?


	


   Yes



 	  Quote: 	
		    It this simply a case of personal bias against 

 any endurance bus requiring >8A because you 

 deem it generally unnecessary and a little more 

 costly and a little bit heavier? Just trying to understand your position here.


	


   It's not about the SD-20 vs any other alternator. It's

   about substitutions in the recipe for success represented

   by Z-13/8.



 	  Quote: 	
		    Another way of saying this: are the FMEA for 

 both the Z-13/8 and Z-13/20 essentially equivalent / identical?


	


   Yes . . .



 	  Quote: 	
		    If this is the case I am still baffled by the 

 continued strong position against Z-13/20 to 

 the extent that you have completely disavowed 

 it like a red-headed bastard step-child, 

 pulling it from your website and other publications.


	


   If you could fit 55W halogen bulbs to your tail

   lights, it would certainly ALTER the way the

   tail lights function with respect to their

   original design goals.



   The folks who spent considerable time figuring

   out the most cost effective ways to offer functional

   tail lights would probably prefer that you did not

   credit them with the idea of 'upgrading' to 55W

   bulbs. It's just that simple.



   I've received drawings in the mail where builders

   have claimed to base their creation on one of the

   Z-figures . . . or perhaps a stirring together of

   several Z-figures. They're hopeful that I'll somehow

   bless their creation or offer what ever "corrections"

   are deemed necessary. I have to decline to debug

   their NEW system as part of my commitment to the

   'Connection and this List . . . and suggest that

   they commission me at my usual rate to customize

   a system to their design goals.

 	  Quote: 	
		  I still have an uneasy feeling that I must be 

missing something, that there must be more to it 

given your continued and strong position on 

this, but for the life of me, I don’t know what it is.


	


   My position is simple. I've offered a number of

   suggestions for architectures that include notes

   describing design goals, functionality and sizing

   of components. One COULD integrate two 100A

   alternators into something that looks like Z-13/8

   but it's NOT Z-13/8, or Z-13/100 . . . it's

   something else.



   Just because Bob Nuckolls doesn't want to lend

   his "blessing" to such a system doesn't mean

   that it's unsafe, or even difficult to do. What

   it does mean that THIS particular combination

   of hardware doesn't fit a recipe for success

   that's been matched to an airframe and a mission

   in concert with the spirit and intent of the

   AeroElectric Connection and this List.



   I'm not the FAA. I have no ability or slightest

   desire to twist anyone's arm to do or not do

   anything. There are plenty of folks here on the

   List who can help sort out errors of sizing,

   failure modes or functionality. But as soon as

   any one of us offers such service, does this

   translate into any sort of "blessing" by those

   who offered assistance?  By the same token,

   if one wishes to stir new ingredients into

   what used to look like Z-13/8, then we're

   talking about a new system.



   I've been thrashing through the design studies

   for a two-alternator, two-battery system that

   makes sense for an electrically dependent airplane

   with failure tolerance loads that far exceed

   8A . . . I.e., an SD-20 or even larger alternators

   can be considered when necessary to meet anticipated

   failure modes. It will be Z-8. It will be something

   I'll happily stand up to defend and modify as

   necessary to correct flaws of design/logic.



   Bob . . .

user9253

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

Posted: Wed Mar 03, 2010 6:28 am Post subject: Re: Z13/20

David Lamb,

I agree with rck that a relay is better than a switch between the battery and the E-Bus.  RCK mentioned the current handling abilities of the switch.  There is another issue: In case of smoke in the cockpit, there is no way to shut off power to the E-Bus switch.  A relay will give you the ability to open the circuit on the engine side of the firewall.

  The ANL fuse is on the wrong end of the #10 wire.  A fuse and a fuselink are not both needed, although having both does not hurt anything.  The protection device should be as close as practical to the battery contactor.  The intent is to prevent excessive battery current in case of a short circuit.  No fuse is required to protect the alternator output because the alternator current is self limiting.

  Is there over-voltage protection for the main alternator?

Joe

_________________
Joe Gores

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