REFLECTOR: Electrical system

Lawrence Epstein ljepstein at hotmail.com
Wed Jul 3 19:09:27 CDT 2013 

I would strongly consider 28V system. Built in backup (2x as much reserve)
and you can use 24 ga wire for everything except battery lead/ignition. Of
course, many components will be more expensive.

My $0.02


On Wed, Jul 3, 2013 at 4:10 PM, Jack Prock <jackprock at wavecable.com> wrote:

>   Reiff,
>
> The only thing that I would add is that you start your engine using the
> battery, but fly using your alternator(s).  If you were going
> to decide between having a duplicate of one OR the other, I would go with
> a duplicate alternator.
>
> If the battery goes out, you can’t start... get jumper cables, start the
> engine, you’re on your way... just like a car. (assuming 12 volt system [image:
> Smile])
>
> If your single alternator goes out, you run on your battery(s) until
> it/they die (while you look for a place to land)...
> at night... over mountains, not a good scenario!!  Other backups will
> help... but the pucker factor goes way up when
> (almost) everything goes dark!
>
> The consequences of one, far outweigh the consequences of the other.
>
> That is just my opinion... and just like assholes, everyone has one!!
>
> Jack
>
>  *From:* Reiff Lorenz <Reiff at lorenz.com>
> *Sent:* Wednesday, July 03, 2013 12:24 PM
> *To:* Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
> *Subject:* Re: REFLECTOR: Electrical system
>
>
> ****
>
> Terry,****
>
> ****
>
> Thank you for all the details. This is all very helpful. I like your
> suggestion about the heat-shrink labeling, even though it's expensive. For
> planning/drawing software I'm leaning toward Visio. (Turbo-CAD does have
> some good features, too.)****
>
> ****
>
> I'm still working on the right tradeoff between redundancy and complexity.
> Lots of suggestions from other builders to do 2 batteries. Others say 1
> battery and 2 alternators. Andy Millin sent me his diagram and he's got 3
> batteries! The Vertical power system simplifies some of this. They have
> multiple configurations for dual batteries and/or dual alternators and/or
> ground power plugs, but it's still not as easy as connecting everything to
> one box. ****
>
> ****
>
> Builder Bill Stockman lives near me. He's retro-fitting his long-wing SE
> with a Vertical Power system and a Garmin G3X. I'm hoping to be able to
> help him and learn about wiring a VP system in the process.****
>
> ****
>
> I may have similar W&B issues to what you describe. I'm a skinny guy and
> don't want to have trim issues, but I also want to take some of my larger
> friends in the front seat (6'3 & 260 lbs.)  Maybe there's some middle
> ground between the two extremes?****
>
> ****
>
> Looking forward to talking to you at Oshkosh!****
>
> ****
>
> Reiff****
>
> ****
>
> ****
>
> ****
>
> *From:* reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] *On
> Behalf Of *Terry Miles
> *Sent:* Tuesday, July 2, 2013 11:46 PM
> *To:* Velocity Aircraft Owners and Builders list
> *Subject:* Re: REFLECTOR: Electrical system****
>
> ****
>
> Wow.  Dave, that is a very nice summary.  I did all of my wiring...every
> inch, every connector, every everything.  I would repeat a lot of what you
> offered, if asked, and that is:  keep track of wire size to fit the current
> load, secure stuff properly so it cannot rub against anything,  (I used
> that black wax lace stuff.  Yank on every connector after you make it to
> test it.   Check every BNC you make for continuity and twist it around a
> little before you declare it sound.   If you make 25 pin connectors
> becareful with pin crimps, and especially the outboard most pins when you
> go to secure the entire bundle.  (You can google how to tied the knots.)  I
> read all the Nuckols stuff faithfully as I educated myself and choose
> against the double alternators, but I do have a pair of Odessey 925
> batteries located forward of the carnard bulkhead in the RG and have not
> had water issues so far.   The main distribution is after of the carnard
> bulkhead.   I did the 2 batts in part for wgt and bal since I am 150 pounds
> and heard stories of trim issues.  While it is another discussion,  the
> decision for one or two batts was and always will be debatable.  It might
> have been better for me to use removable ballast since I cannot take
> anybody much over 200 lbs and put them in the front seat.  My inflight draw
> is about 4 amps, much much different from days gone by.  I will run out of
> gas before I every run out of batt power.  I replace one batt every 18
> months to two years.  ****
>
> ****
>
> Making wire streams (I like that term) would have been some good advice
> for me.  I didn't do that and actually installed the wiring a little at a
> time and added a lot of after the fact stuff....and I do have a lot of
> loose single wires going hither and yon (sp?) back and forth from port to
> starboard behind the instrument panel.  I used auto fusing mostly but do
> have about a dozen in view aircraft grade CB's for stuff I want to know
> about...ignition, transponder, hydro pump and gear control gizmo...stuff
> like that.  There are also decisions about putting more than one component
> into a single fuse/breaker.  ****
>
> ****
>
> I bought a $300 plus wire labeling system that uses heat shrink.  The dam
> heat shrink refills were about 35 cents an inch, but I thought that was
> money well spent, as well as being able to work at a base level with
> turbo-cad to do the drawings since I experienced endless edits in that
> department from my first paper drawings.    ****
>
> ****
>
> If you do your own wiring, I would call Dave first since he offered.  I am
> only a Saturday afternoon electrician-avionics tech, but I can certainly
> add my name if you want an opinion about doing your own harness and/or
> tacking the job of installing all of the avionics and doing those 2
> gazillion settings on your own.  Being able to buy both an AHRS and an
> autopilot from the same vendor is a big plus not available to me.  I have
> GRT stuff and I like it.  Besides buying mil spec wire, buying high grade
> teflon tape is a good idea too.  ****
>
> ****
>
> Terry****
>  ------------------------------
>
> To: reflector at tvbf.org
> From: dtnelson at us.ibm.com
> Date: Sun, 30 Jun 2013 10:36:59 -0500
> Subject: Re: REFLECTOR: Electrical system
>
> Hi Reiff,
>
> The power and ground bus bars I'm talking about is behind the canard
> bulkhead in the area behind the panel - not forward of the bulkhead and
> exposed.
>
> In general, for exposed connections, the worry wouldn't be failure due to
> shorting from the water, it'd be corrosion.  In general, galvanic corrosion
> should be considered, but can be easily controlled with HW store
> electrician's grease.  The relays and connections that I do have on the
> forward (exposed) side of my bulkhead all have a dab of that stuff (main
> contactor, hydraulic pump relays, battery connections, etc.).
>
> I've never seen galvanic corrosion on my homemade brass bus bars & the
> bimetal ring connectors I've used.
>
> I've seen the other comments re. use of two alternators, etc. I agree with
> the guidance from Richard Gentil - if you've got an electrical problem
> you're going to want to land and fix it anyway.  Keeping your system as
> simple as possible and building your simple system with reliability in mind
> makes much more sense to me than trying to add all kinds of redundancy...
> which just gives Murphy more opportunities to ruin your day.  I'd think
> really hard before installing a system with two alternators, two batteries,
> all kinds of switching relays, lots of extra wiring... failure points...
> and things to go wrong.
>
> My two cents.
>
> Dave
>
> Dave T. Nelson
> T/L 553-4327, Voice 507-253-4327, Fax 507-253-3648
> Program Director, ISC ECAT NPI & Test Engineering
>
> Dave,
>
> Terrific advice! Thanks for all the help.
>
> Did you cover the power buss with anything? Is there any concern of having
> a "naked" power buss in the nose? I have an RG, so I'm imagining the entire
> inside of the nose will get wet if I take off or land in the rain.
>
> I really appreciate all the info!
>
> Reiff
>
>
> *From:* reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org<reflector-bounces at tvbf.org>]
> *On Behalf Of *Dave T Nelson*
> Sent:* Saturday, June 29, 2013 1:12 PM*
> To:* reflector at tvbf.org*
> Subject:* Re: REFLECTOR: Electrical system
>
> This is an excellent area for KISS.... Keep It SIMPLE!
>
> In my installation, I used two connection blocks in the area behind the
> instrument panel for both 12V and ground (4 total), one of each flavor on
> the left and on the right.  I made them myself by soldering brass screws
> into a brass plate.  I then used ring terminals on the wire ends.  The
> terminals are then held tight with MS21042 nuts.  The idea is to avoid
> having to have wires seeking 12V or ground from having to cross the whole
> panel from the left side to the right (or vise-versa).  The ground system
> should be simple - everything has only one grounding point (to avoid ground
> loops).  On both power and ground, the buss bars are powered (or grounded)
> via two wires for redundancy.
>
> I used switch circuit breakers instead of switches with separate circuit
> breakers (or fuses).  I wouldn't recommend that... I've had a couple of
> them fail.
>
> I used circuit breakers instead of fuses.  My reasoning was that I want to
> be able to see at a glance if one had popped (hard to do with a fuse).  I
> wish I'd used the type that allow you to pull the end of the circuit
> breaker to switch a circuit off.
>
> Don't buy used circuit breakers!
>
> Use real aviation grade wire, not Radioshack junk.
>
> I used, carefully and religiously, a wire size chart.  I've seen many,
> many installations where folks use wire of way to low of a gauge (too thick
> and heavy).  You'll be surprised how often you can use 20 or even 22 gauge
> based on the current requirements.  Make sure the wiring chart you use is
> for bundled wire, not single strand.  Make sure you use the right size
> terminal for each wire.
>
> I sized the circuit breakers for the load, not for the wire carrying
> capacity.  There has been some debate on this, as Nuckolls would size the
> fuse/circuit breaker for the wire, not the load.  IMHO I'm trying to
> protect the expensive load (radio), and the wire will always be sized with
> a much greater capacity anyway... so the wire is protected if I size the
> fuse for the load.
>
> Pay attention to wire dress... think about your major wiring lanes... try
> to get the wiring to all flow into and out of a lane... which allows you to
> secure a bundle instead of trying to secure individual wires.
>
> Ensure you've got wires secured within a few inches of the connection
> point.  You don't want vibration load to be taken by the connector.  It
> will fail for sure.
>
> If you are handy with a soldering iron, don't be afraid to use it - as
> long as you are securing the soldered joint from vibration.
>
> As I said, I chose ring terminals instead of spades... I want to be able
> to count on a lock nut for security.  Don't by hardware store connectors -
> don't!  Get good quality bimetal crimp connectors (3M makes good ones).
> Use a real rachetting crimp tool, not a hardware store special.
>
> I *hate* cable ties... no matter how carefully you cut the ends off,
> they'll leave sharp edges that'll get you at some point.  I used nylon wire
> tie string instead... it works great, it's easy to use, and it'll never
> bite you.
>
> The only relays in my plane are the main electrical and starter
> solenoids.  I know they've gotten much more reliable through the years, but
> I'm still shy of using them.  I don't know where they'd do something that
> there isn't an easy way to do without them.
>
> I grew up as a ham radio operator, worked in a TV repair shop through HS,
> and as a technician wiring satellites in college.  That (and my BSEE) form
> my opinions on this stuff.  I enjoy pulling wire and I believe I'm good at
> it.  I'm coming up on 1100 hours on my Velocity, and had 900+ hours on a
> Varieze I built first - with zero wiring induced issues.
>
> Happy to discuss if you'd like to call.
>
> Dave
>
> Dave T. Nelson
> T/L 553-4327, Voice 507-253-4327, Fax 507-253-3648
> Program Director, ISC ECAT NPI & Test Engineering
>
> ----- Message from Reiff Lorenz <Reiff at Lorenz.com> on Sat, 29 Jun 2013
> 09:55:22 -0400 -----  ****
>
> *To:*****
>
> "reflector at tvbf.org" <reflector at tvbf.org>****
>
> *Subject:*****
>
> REFLECTOR: Electrical system - basic components****
>
>
> I'm starting work on the electrical system. I could use some
> recommendations on what to purchase (or how to make) these items and where
> you installed them:
>   ****
>
> ·         Main bus
> ·         Main ground block
> ·         Firewall ground block
> ·         Avionics ground****
>
>
> I'm going to use the Vertical Power system for switching & circuit
> breakers so a combination bus/CB system won't be necessary. Should I just
> buy some copper bar and drill screw-holes in it? Is there a good, basic bus
> product that works well? Where did you mount it and how did you protect the
> power buses from accidental grounding?
>
> Thanks!
>
> *
> Reiff Lorenz, Dayton, OH*
> Velocity XL-RG, 45% complete
> Currently working on: Mounting the battery, main contactor, starter
> contactor, and RG control system.
> *
> Velocity Owners and Builders Association**
> *http://www.VelocityOwners.com <http://www.velocityowners.com/>
> _______________________________________________
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