REFLECTOR: Using the starter supply(+) wire as a charge wire

Terry Miles terrence_miles at hotmail.com
Sun Jan 28 21:08:05 CST 2007


Joe,

Thanks for the new ideas to consider.  I am such a fledgling at all this,
the topics, the problems, the various fixes are a far bigger expanse of
knowledge than I every expected this to be.  I will get back to you next
week.  It's late Sunday and I try to sit quietly some each Sunday nite, and
if I don't shut off this damn computer it won't happen.  That said, I want
to say I have been pouring over Nuckols's Frequently Asked Questions PDF on
his web site.  It runs 300 some pages and is full of very well formed
questions and some very helpful answers.  That's not to say I am a Nuckols
groupie, but he is an enormous source of very well organized information
once you find where it all is.  

 

I have been off line swapping ideas w/ Jim Agnew and that coupled w/ what
you have and what Scott D and Sid and Dave and others have offered, I am
thinking now to protect both segments of my Alternator B lead to Main bus
feed wire.  

 

The basic rule is to protect the wire.  I think we all know that.  "It is
written"  that you protect with a protection device placed physically as
near to the energy source as you can do it, limited by installation issues
we all have to face.  In the case of an alternator malfunctions, things are
a bit bass ackwards.  The ALT cannot damage it's own output wiring.  Mine is
rated at 60a and that's all it can ever do.   It is the battery that is the
damage-doing-device in the event of alternator mechanical or electrical
malfunctions.  I will have two wire segments to consider.  From the ALT:
The first is B-lead to Starter lug.  The 2nd segment is starter lug back to
switched side of the master contactor in the nose.  For segment #1 I will
use a slow blow B&C current limiter-which is probably a waste of money, but
I already bought the damn thing.  For segment #2 which is the 2awg wire down
the utility channel to the starter segment I will fuse it at 60 amps at the
main fuse block. Given the likelihood that a serious hard fault is the main
protection issue here, the CB is always going to beat the current limiter
given the physics of the different device guts.   

 

For now, I don't have the engine running so I may be missing parts or
control or protections issues here as I try to assimilate all the info into
a working system-which I am beginning to see is MUCH different from the
paper design!  Also, using the Nuckols drawings as a crutch, I am working
with the B&C alternator w/ an external V-regulator.  Touching on a new topic
now:  He uses a fusible link to protect the wire run from the main bus to
the input side of alternator on/off sw  and then the sw output routes thru a
main bus 5a CB out to the B&C external V-reg which controls ALT output.   

 

I hope I answered some concerns, explained my confusions, and as always, I
am all ears for the advice of those who tromped this road before me.   

 

Thanks,

Terry

 

  _____  

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Joe Ewen
Sent: Sunday, January 28, 2007 8:59 PM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Using the starter supply(+) wire as a charge wire

 

Terry,

An ANL is a one time fuse, an overload will leave you with out an
alternator.  You may want to consider a Type 1 auto reset circuit breaker.
It will break under overload and will reset when the overload clears.
http://www.delcity.net/delcity/servlet/catalog?parentid=193071
<http://www.delcity.net/delcity/servlet/catalog?parentid=193071&page=1>
&page=1

 

On your earlier discussions about amp meters, you may want to consider an
Hall Effect Current Sensor rather than a shunt.  The sensor is a donut shape
component that fits around a wire with no exposed connections.  It provides
a signal proportional to current flow and direction.
http://www.ampsense.com/

 

Joe

 

----- Original Message ----- 

From: Terry <mailto:terrence_miles at hotmail.com>  Miles 

To: 'Jim Agnew' <mailto:Jim_Agnew_2 at yahoo.com>  ; 'Velocity
<mailto:reflector at tvbf.org>  Aircraft Owners and Builders list' 

Sent: Saturday, January 27, 2007 10:33 PM

Subject: Re: REFLECTOR: Using the starter supply(+) wire as a charge wire

 

Thanks,Jim.  Sorry.  In a earlier post about this I mentioned, there will be
an 60a ANL current limiter between the B lead and the wire run back to
starter lug.

Terry

 


  _____  


From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Jim Agnew
Sent: Saturday, January 27, 2007 3:44 PM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Using the starter supply(+) wire as a charge wire

 

You can do this however remember that the starter cable is like a welding
cable and without any circuit breaker protection so a short will cause a
fire!  That is the reason for the starter relay to minimize the length of
the unprotected wire.  You normally have a CB in the alternator power lead.

 

Jim


 

James F. Agnew
Jim_Agnew_2 at Yahoo.Com
Tampa, FL
Velocity 173 Elite Aircraft Completed & Flying 

 

----- Original Message ----
From: Al Gietzen <ALVentures at cox.net>
To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
Sent: Saturday, January 27, 2007 12:34:00 PM
Subject: Re: REFLECTOR: Using the starter supply(+) wire as a charge wire

I talked w/ Skytec starters today.  On their web site they talk about an
alternative wiring scheme that eliminates the normal firewall starter
contactor which is required on certified span cans.  I can wire my starter
button directly to the coil/contactor that is bolted to the Skytec starter
instead doing the conventional route of contactor in the nose that then
ports juice to the Skytec contactor and its starter motor.

 

Terry;

 

I don't know about the Skytec, but typically the solenoid/contactor on the
starter takes a significant current, and has a very large in-rush current.
I think you'd would want a switch rated to 30-40 A; with spike suppression,
for reliability.  I used a automotive 40 A relay for the job (also with a
TVS) so I could use a light duty push button up front.

 

Al

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