Avionics busses

[Av8rRob]

Just wondering in todays world of G3X?s what people are putting on their avionics buss. I would assume that the PFD and GEA 24 is not on that buss to allow for engine instruments to be displayed during start. What are you planning or doing? Do you turn on the avionics bus only after engine start or is it just an easy means of load shedding in case of an alternator issue?

[Nova RV]

Originally Posted by Av8rRob

Just wondering in todays world of G3X?s what people are putting on their avionics buss. I would assume that the PFD and GEA 24 is not on that buss to allow for engine instruments to be displayed during start. What are you planning or doing? Do you turn on the avionics bus only after engine start or is it just an easy means of load shedding in case of an alternator issue?

I have all of the avionics on the avionics bus but with the G3X system, the PFD and GEA etc. can also be fed from a back up battery with a separate input wire to each device so I turn on the stby battery first and get PFD and GEA then start engine and turn on the avionics bus which leaves the stby battery connected but not feeding power unless the bus voltage drops too far (don't remember the value). I can load shed individual items via pullable CBs.

[9GT]

You can also install a Garmin GAD 27. This nice little unit does some pretty cool stuff. https://buy.garmin.com/en-US/US/p/521821

[DRMA]

At the recommendation of Jason with Aerotronics, I have placed the following on my avionics bus:
- GMC 305 (A/P Contr.)
- GSA 28 (AP Pitch & Roll Servos)
- GSA 28 (Yaw Servo)
- GTR 20 (Com 1)
- GMA 245 (Audio Pnl)
- GTX 45R (Xpnder/ADS-B Rx)
- GTN 650 Nav (GPS Nav)
- GTN 650 Com (Com 2)

Everything else is on the main bus, with some items tied into a smaller battery backup system (TCW IBBS). All items are fed from circuit breakers which can be individual opened if necessary.

Hope this helps a bit.
Cheers

[GalinHdz]

Originally Posted by DRMA

At the recommendation of Jason with Aerotronics, I have placed the following on my avionics bus:
- GMC 305 (A/P Contr.)
- GSA 28 (AP Pitch & Roll Servos)
- GSA 28 (Yaw Servo)
- GTR 20 (Com 1)
- GMA 245 (Audio Pnl)
- GTX 45R (Xpnder/ADS-B Rx)
- GTN 650 Nav (GPS Nav)
- GTN 650 Com (Com 2)

Everything else is on the main bus, with some items tied into a smaller battery backup system (TCW IBBS). All items are fed from circuit breakers which can be individual opened if necessary.

Hope this helps a bit.
Cheers

Along the same lines of how I have mine.


FWIW: When I built my panel back in 2012 I had 3 spare circuit breaker locations, 1 in the Avionics Buss and 2 in the Main buss. Since then I have used all 3 of them up and would have liked to have a few more.

[Av8rRob]

Originally Posted by 9GT

You can also install a Garmin GAD 27. This nice little unit does some pretty cool stuff. https://buy.garmin.com/en-US/US/p/521821

So, I assume you mean that the GAD 27 has a voltage stabilization feature that you use to prevent a brownout i stead of load shedding a la avionics bus, correct?

[GeoffP]

Originally Posted by Av8rRob

Just wondering in todays world of G3X?s what people are putting on their avionics buss. I would assume that the PFD and GEA 24 is not on that buss to allow for engine instruments to be displayed during start. What are you planning or doing? Do you turn on the avionics bus only after engine start or is it just an easy means of load shedding in case of an alternator issue?

Although I'm still a way off doing this in my RV-9, I was planning a G3X PFD & MFD, with a G5 backup (with the integrated battery), and complementing all this with a TCW IBBS system. I'll run as many things as I can through the back-up (Engine Monitoring, Radio, Displays), and it will serve to power the avionics I need at start-up. Behind the scenes I was going to use a VP-X. This is for a VFR aircraft so technically I probably don't need that much redundancy but I figure that I'll aim to be able to keep flying for 1-2hrs in the event of an Alternator / main battery failure.