Dbro172

Dbro172

Well Known Member
For those running the multiple screen G3X how do you power them up. I planned to have an avionics master switch. Should I run the PFD off the Master Power and the MFD off the Avionics Master? (That's how the G1000 is setup in a 172)

Suggestions?
 
I think most people will have an Aux Batt bus that their G3X system is connected to. This provides power during startup that is isolated from the main power bus and it provides a source of backup power if the main bus goes down during flight.

In my case, I have an Aux Batt Bus that will get switched on before startup. It will turn on the MFD, PFD, GSU and the backup GEMINI PFD. This switch will stay on for the duration of the flight.

When the master is turned on for start, my VP-X and the MFD gets power from the main bus. This is so they can start talking to each other. Once the engine is running, the avionics switch comes on and all of the rest of the avionics are turned on by that switch. Since the MFD, PFD, GSU and Gemini were already powered up, they just transfer their load to the main bus. Diodes take care of the aux/main bus switching automatically and it is seamless to the user.
 
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My TCW turns on the G3X system separately, then after startup the avionics master takes over. Not flying yet...smoke test approaching...so design may change but that's easy enough with the VPX.
 
My TCW starts my PFD 1, MFD, GMU 44 and GSU 73 with an "AUX" power switch. My master also engages the TCW backup battery. Avionics power engages the PFD 2. This way I can watch the two screens during the start and be ready for taxi quicker.
 
I have all three screens on the aux buss, along with the 430, sl30, pm8000, and peripheral equipment. The avionics master also turns all of the avionics on including the non essential items. I always turn on the aux buss first, let all the equipment boot and the ahars erect. This allows me to obtain wx, program my flight plan and get a clearance, if required. The G1000 cessnas are setup with a dual buss system also, in this way the main battery is only used to start the aircraft and the avionics equipment is protected from a voltage spike or possible voltage drop during cranking causing a re-boot if the voltage falls to below minimums.
Since you are designing a very capable panel, you also seriously consider adding a very capable backup system.

Brantel, the VPX system will work just fine without the EFIS up and running, and the EFIS will work just fine without the VPX.
 
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Bill.Peyton said:
I have all three screens on the aux buss, along with the 430, sl30, pm8000, and peripheral equipment. The avionics master also turns all of the avionics on including the non essential items. I always turn on the aux buss first, let all the equipment boot and the ahars erect. .
Click to expand...

Am i reading this right?.... Your avionics master switch powers the mentioned devices from an auxilary battery source? Once the master is thrown the primary battery source prevails? Or, you have an avionics master switch AND an auxilary battery source???
 
I have a dual buss system, 2 batteries etc. The main battery/buss is the normal operating source for the avionics. The avionics master resides on the main buss. I also am using the vertical power. VPX system to manage the main buss power system.
Once the engine has started and the charging system operating, the avionics master is activated and no current is drawn from the aux buss. It continues to charge in flight and is available if required and the main buss or the vertical power system were to fail.
The garmin g3x system has provisions built in for a secondary power source, so does the 430W.
 
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