REFLECTOR: Bus, Battery & Back Order

[Craig and/or Denise Woolston]

John and I are going a little different than what some are doing but
basically the same.

We have the Continental 70amp main alternator and 24aH as the Main bus.  We
have a B&C 20amp and 17aH Essential alternator.  The plan is to only use the
Main as the starting.  The Essential powers the BM G3 with autopilot,
EIS6000, SL-30, Transponder and annuciators.  The Main powers the dual
screen, single AHRS GRT system.  Both are regulated by B&C regulators with
Low Volt warning lights.  There is a crossfeed switch if you need both
batteries for starting (cold or dead main) or for failure conditions.

I did this to facilitate EI and FADEC in the future.  Decided to wait for
the dust to settle on the FADEC and the engine came with brand new mags so
it's over kill for now, but looking ahead...  Also wanted to power
separately the attitude sources.  I know its belt and suspenders but it's
what I feel comfortable flying into a cloud with my family in the back.

For either alternator failure, you can crossfeed when your ready and load
shed until the low voltage lamp stops flashing.  Or you can leave it alone
and the power with last longer than the tanks.  The essential bus battery
will be replaced at every annual.  It just so happens to fit my JetSki which
always seems to need a new battery every year anyway...

I plan to have a jack for a handheld radio to pipe into aircraft antennas
and a handheld GPS for backup.

We are (cross my fingers) a day or two from lighting the whole thing up...

Craig Woolston
XL-5FG in Plamdale,CA

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Terrence Miles
Sent: Wednesday, June 15, 2005 11:27 AM
To: reflector at tvbf.org
Subject: REFLECTOR: Bus, Battery & Back Order


Hi to everyone but in particular to Brian, Keith, Al G, and Kurt who I think

are deep into wire issues.

Here's what I got.

For Electrics:  Here's my current plan and why.  Two big batts in the nose.

One stacked on top of the other.  For now I am going to slap the ground 
leads together and run them in parallel with B&C L60 alternator (60 amps) 
and the B&C external voltage regulator and the o'volt protection.

I may one day with not a lot of effort, put in a 2nd aux battery contactor, 
but I see its practical value as limited due to what follows next.

I have decided in favor of a single power bus.  I can't see a strong enuf 
reason to break things into separate buses to power up or shed in event of 
alternator problems.  I will instead pull out a checklist and do a load shed

procedure at each components control head/ panel switch/CB/whatever.  (Two 
mags, by the way until I have her in the air and de-bugged)

When I re-read the Nuckols stuff  on dual batt & single alt, I decided it 
wasn't for guys like me.  I can put two equal amphr batts right side by 
side...read no #2awg wires running all over hell.  I don't have dual EI's.  
Sure as sh--t the day I loss a alternator would be the day the #1 comm would

be TU and I have to repower the main load buss to access #2 comm and get 
myself confused say 2 years down the road by which time all the electron 
theory will be faded into dim memory.

GRT stuff:  Single AHRS system, 2 screens, EIS in the radio stack, no 
airspeed&Alt add-on to the EIS in favor of round dials below the GRT 
screeens.  Decided basically to abandon the two spare power leads.  I am 
told a solenoid controlled contact can draw an amp to 1.5 amps just to hold 
closed, and the diodes will cost you a volt in pressure.

Some of the above was driven by electrical abnormal checklist drafting.  
Some from the local tower operator/Cozy guy/ex USAF avionics tech.  For 
backup, his personal philos is a bag of external hand helds.

What do you four think of this?  Anybody else want to chime in?

I called Affordable panels this week.  He is an RV vendor...uses the 
Approach Hub stuff.  He is very backed up.  I am looking to make the major 
buy with Stein Air.  Anybody have any comments on him?

Where's everybody else on this topic.  Are you guys going to wire up your 
own intercomponents in the avionics rack?

Last but not least...anybody else waiting for engine mounts and exhaust 
systems besides me??

Regards,
Terry

Regards,
Terry


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