Electrical System Planning - Input requested

[N941WR]

Oh, and I didn't see anything for interior or panel lights.

A cool trick Bret Smith did was to put very small white LED's under the wings, close to the tie-down rings and wired to the position lights. He did that to help when tying the plane down on a dark ramp.

[akarmy]

Originally Posted by MCA

Any reason you need those items on the battery bus? You could eliminate the batt bus altogether and put those on the main bus. Also, why are there switches on those two items?

My thinking was to be able to switch them on without the master on so you could charge a cell phone or iPad while sitting parked (like when camping or traveling somewhere) for the USB ports, then the 12v one I use for trickle charging the battery so it's nice to switch on direct to the battery then switch off so it's not active all the time.

Thinking about it, I think you are right about the USB moving to the main bus, not really that much usage for that charge situation and the risk of leaving the device charging in the plane unattended is not the best.

Maybe move the 12V charge port to a single inline fuse and eliminate the battery bus.

Originally Posted by MCA

P-Mags should have a switch so you can test the on-board generator.

Yes I'll use a multi position switch for each PMAG allowing both p-lead and power to be cut to test them.

Originally Posted by MCA

Do you want switches on the exterior lights?

Electric trim? What type of flap control?

Yes lights will be switched, with double throw, off-taxi-landing + a separate wig-wag. Same for off-nav-strobe for the other switch.

no electric trims - all manual

A basic manual up / down flap control wired through a (down)-off-(up) switch.

Originally Posted by MCA

Why do you have a fusible link for the alt field? Why not a 5A breaker? Also, you have both 18 & 20 AWG wire for the field. Recommend 18 for all.

The fuse link is to protect the wire between the main bus lead and the switch all before the 5A breaker. Since there will be a bit of distance to go to the switch panel first.

Thanks for all the input!

[akarmy]

Originally Posted by Noah

Having the alternator B-lead attach to the main contactor rather than the starter contactor eliminates a failure point (the starter terminal).

Good point.

Originally Posted by Noah

Also the avionics bus switch is a single point failure.

Yep, I'm ok with that, as my "avionics" is a single screen dynon with battery backup, really I'm only loosing the com radio / transponder.

[akarmy]

Originally Posted by krw5927

Have you already installed the Advanced AOA? If so, then disregard. If not, a perfectly fine AOA indication can be had on Skyview, either using the Dynon pitot or making your own.

I would be happy with the Dynon AOA if they would produce an external indicator. As they have not, I'm going with AFS so I can put the display on top of the glare shield. I had this setup in my 9A and just loved it. So easy to make landings having AOA in your field of vision while looking out at the runway. I will be using the AFS / Dynon probe that includes the AOA data so I could also feed it to both systems for redundancy, but not sure that's needed.

[akarmy]

Originally Posted by N941WR

I don't see fuses for your landing, taxi, and position lights. Since your -8 will be a trail dragger, you want to switch your landing and taxi lights independently. That is because your landing light will be aimed parallel to your wings and the taxi light will be aimed down.

Yep, i'll have a progressive switch so off-taxi-landing positions to accommodate. The lights are a new design from AeroLED which should be pretty neat. Guess the question is, do I need to be able to have them both on at the same time?

Originally Posted by N941WR

I don't see a fuse for your Dynon's engine module, which should be on the main buss.

The Skyview EMS takes it's power from the SV-Net cable, not dedicated power (I think).

Originally Posted by N941WR

Regarding your P-mags, you can always use pullable breakers, which will allow you to drop power to them, for your pre-flight. (That or look at how I wired mine.)

Yes I'll do something like you did, or G-IKON's switch config. But basically yes switched power and p-lead to test everything.

Originally Posted by N941WR

Placing the wire size on your schematic for each circuit would be helpful.

Yep, will do.

[AF_Alan]

I have very similar set up.

I'd up the Aux power port to 10A to cover anything you might want to plug in, just like in a car

Dynon EMS uses a fused input for voltage, I used 3A I believe

10A for LED nav/strobe seems high. I don't know what their landing lights need.

#22 awg on a 5A breaker? As posted already, recommend 18awg for alt field

My PP alt has OV internal so just field, bat, and indicator (failure light) wires to unit.

Good luck

[Mich48041]

Bob Nuckolls article on avionics master switches can be read here:http://www.aeroelectric.com/articles/avmaster.pdf
After reading that, it seems that installing an avionics master switch trades an imagined monetary
danger (damage to avionics) for a real safety of flight danger (loss of all avionics).
There is a way to address both dangers, perceived and real. Install some more switches.
Miniature toggle switches take up very little panel space.
If space is limited, two loads could share one switch.
One bus can supply current to all loads, no need for a separate bus.
Joe Gores

[rocketbob]

I have found starter solenoids to be redundant and an extra failure point. At 350A a small amount of resistance in the circuit will degrade starter performance. The starter already has a solenoid built-in. I don't wire them in. As long as the starter cable is properly supported and maintained it will never be a problem.

[tim2542]

If your worried about an avionics switch failure you can use a DPDT 3 position switch. Wired properly you have a backup set of contacts standing by if needed.
Agree on dumping the E bus, I have a small brown out/Aux battery on my plane and an E bus. After flying now I realize I have a belt, suspenders and duct tape holding my pants up. It's a bit silly for most missions.
I'm not saying the E bus isn't a good idea on some planes/missions.
Tim

[akarmy]

Originally Posted by rocketbob

I have found starter solenoids to be redundant and an extra failure point. At 350A a small amount of resistance in the circuit will degrade starter performance. The starter already has a solenoid built-in. I don't wire them in. As long as the starter cable is properly supported and maintained it will never be a problem.

Hi Bob,

I pulled the archives on the topic and am convinced, one question, is there a similar solution for the B&C starter, I have not seen any mention if it can be wired in a similar fashion?

Looking at my Aerosport quote, it lists a skytec inline starter??? Is that the NL series? hum.