Battery Monitoring

I ended up with two EarthX ETX900-VNT batteries in N5412K. To monitor the batteries, I have a couple of things going on. First off, I have the battery fault ground wire coming all the way up to my panel where there is a red led (79-2977-ND) on my panel right next to my Master and Aux bus switches. In the event that there is a failure with one or both of the batteries, this LED will flash with an error status.




The error codes for the battery are as follows:


The second monitoring system on the batteries is the Garmin G3X with a GEA24. I have the GEA24 configured to display the volts and current for both the MASTER and AUX bus. The Volts 1 and amps fields are fed from the VPX-Pro serial line to display the MASTER status. The AUX volts (volts2) is fed from the GEA24 Aircraft Power 2 line (which is connected to my AUX fuseblock). The AUX amps (amps2) is fed from a shunt I have on my AUX bus near the fuseblock.

The shunt has a 1A fuselink (F2313-ND) on each one of the lines. Hopefully these never blow, but I did install them in a format that allow them to be easily replaced. Yes this photo is taken before securing the wires.




The G3X / GEA24 is configured to have Red,Yellow, Green bands on the engine display page. Since this is a lithium battery, the settings are a little different than a lead acid. By the time a lithium (12v) gets to ~11.5v it is completely drained. The normal resting voltage is 13.3v. So I configured with the following settings:

• Red: 0-11.5v
• Yellow with Alert: 11.5-13.5v (alternator not charging)
• Green: 13.5-14.9v
• Red: 14.9-16.0v

The Main alternator is a AL12-EE70/B while the backup is a FS1-14B. Only one alternator will be live at any given point in time and the switch over between the two is a manual operation via a physical panel switch that controls the VPX ALT1 and ALT2 power pins. The alternators do come together at the firewall pass through, so the alternators only ever feed the MASTER bus. The AUX bus gets charged via the X-Feed contactor (via the MASTER bus). This makes the AMP alert settings a little more complex. 


The AUX bus consists or a battery, contactor, a 6 Ga wire coming forward to the mid-panel where a fuseblock distributes the AUX power to the backup power pins of the essential avionics. The 6 Ga wire is the limiting factor for this bus. Let's be super conservative and say that in our 10ft run we don't want to exceed 30As. I do not have 30As of avionics even hooked up to this... So for the AUX bus I have the following

Red: 0-2A 

Green: 2-20A

Yellow: 20-25A

Red: 25-30A 

The thought here is that we are watching how much power is getting sinked into the system, not the amount of current going into the system (alternator shunt). So if the plane is on, we should have at least 1A going out of the AUX bus (from what I have been watching I have a consistent 2A with the transponder off). Anywhere from 2-20A is normal. 20A is the sum of all the fuses I have in the AUX fuse block,  so if there is more than 20A indicating, then there is a short between the shunt and the fuseblock (6inches).

The MASTER bus Amp reading gets its data directly from the VPX-Pro via the serial line. The VPX page on the G3X has a pretty nice display for each one of the outputs themselves. I chose to set the color bars on the Master Amp gauge relative to what the main alternator can output. This is a little mis-leading. If I am functioning off of my main alternator, then I have 70As to work with. However, if I have switched over to my backup alternator for some reason, then I only have 30A to work with. So I know how much my VPX is outputting, but I did not put shunts on the alternator lines, so I do not know how much current is coming from the alternators.

Red: 0-4A 

Green: 4-60A

Yellow: 60-65A

Red: 65-70A 

I have to look into this a little later to see if there is anything smart I can do with the GEA24 discrete inputs. I do know that if I have switched over to the backup alternator (for other than just testing), that I am already looking at where and how to land. So I am not sure I care to deep dive too much into this case.

GTN650 G3X wiring

I spent a good hour and a half today trying to figure out how to get the GTN650, GTX45R, and the PFD talking to each other. Finally after getting most of the way there I realized that I was searching the G3X install manual for ARNIC and not ARINC. Towards the end of the G3X installation manual in the interconnect section the proper software settings for both the GDU and the GTN. (that is a lot easier than trying to figure that out by guessing the difference between "format 1" and "format 2").

*Note: to get into the configuration sections of the devices, hold "menu" when booting the GDU and hold "home" when booting the GTN.

RS-232 Configuration Overview

• PFD
• RS232-0: GSU25#1
• GSU25#1: RS232
• Configuration: N/A
• RS232-1: GTN650 
• GTN650: RS232-1
• Configuration: MAPMX
• RS232-2: GTN650
• GTN650: RS232-2
• Configuration: CONNEXT
• RS232-3: GDL51R
• GDL51R: RS232-2
• Configuration: CONNEXT
• RS232-4:
• Not Used
• RS232-5: GTX45R
• GTX45R: RS232-3
• Configuration: CONNEXT
• MFD
• RS232-1:
• RS232-2: GDL51R
• GDL51R: RS232-1
• Configuration: CONNEXT
• RS232-3: Vertical Power
• Vertical Power: RS232
• Configuration: "vertical power"
• RS232-4: GEA24
• GEA24: RS232
• Configuration
• RS232-5: GTX45R
• GTX45R: RS232-3
• Configuration: CONNEXT

The following sections detail the software settings for each of the devices.

Vertical Power (VPX-Pro)

1. On the PFD (GDU 4XX) in configuration mode
1. Under RS-232 page in the setup, set the MFD serial port that is connected to the VP-X Pro to “Vertical Power”. (A green check mark in the left column indicates it is receiving data from the VP-X. )
2. The trim and flaps are automatically configured to read their position from the VP-X. If you have a third trim axis wired into the G3X analog position input, you can configure it in the trim and flap setup as described in the Garmin manual. 
3. You can configure the Amps gauge to display amps from the VP-X instead of from an external shunt.

GDL-51R

 

1. On the GDU 4XX  in configuration mode
1. Under the RS-232 interface setup page set serial port connected to the GDL-51R to "CONNEXT 57600 BAUD" A green check is show next to the connection when communication is established with the GDL51.

GTX-45R

             

1. GSU 25 WITH GTX 45R 
1. NO CONFIGURATION REQUIRED FOR GSU 25 SERIAL PORT 
2. GDU 4XX RECEIVING TRAFFIC/WEATHER FROM GTX 45R 
1. THE GTX MAY BE CONNECTED TO ANY SERIAL (RS-232) PORT ON THE GDU 4XX FROM 1 TO 5. ONE CONNECTION ONLY PER GDU.
2. ON THE GDU 4XX RS-232 CONFIGURATION PAGE 
1. SET SERIAL PORT CONNECTED TO GTX TO "CONNEXT 57600 BAUD" 
3. GTX X45R REMOTE MOUNT TRANSPONDER
1. ON GDU 4XX TRANSPONDER CONFIGURATION PAGE SELECT INSTALLED TRANSPONDER TYPE (E.G. GTX 45R) 
2. CONFIGURE HSDB DEVICES (GTN/GTS ENABLE/DISABLE) 
3. CONFIGURE TRANSPONDER SERIAL PORTS 2,3,4 FOR "CONNEXT FMT 1"
4. CONFIGURE ALL ADS-B OUT DATA FIELDS 
4. GTX X45R REMOTE MOUNT TRANSPONDER INSTALLED WITH GTN IN SYSTEM
1. ON THE GTN INTERFACED EQUIPMENT PAGE
1. SET ADS-B IN SOURCE TO "GTX #1"
2. ON THE PFD1 TRANSPONDER CONFIGURATION PAGE
1. ENABLE "GTN" ON HSDB DEVICES FIELD
5. GTN/GNS POSITION SOURCE
1. WHEN GTN IS CONNECTED TO A GTX 345R/45R USING ETHERNET, SELECT "GTN PRESENT" ON GDU 37X/4XX TRANSPONDER CONFIGURATION PAGE
2. ON THE GTN/GNS RS-232 CONFIGURATION PAGE SET SERIAL PORT OUTPUT CONNECTED TO GTX TO "ADS-B+" OR "ADS-B+ FORMAT 1" 
6. GTX X35R/X45R REMOTE MOUNT TRANSPONDER
1. ON GDU 4XX TRANSPONDER CONFIGURATION PAGE
1. SELECT INSTALLED TRANSPONDER TYPE (E.G. GTX 345R)
2. CONFIGURE SERIAL PORT CONNECTED TO ADS-B POSITION SOURCE TO "ADS-B+"
3. CONFIGURE HSDB DEVICES (GTN/GTS ENABLE/DISABLE)

GTN-650 to PFD

1. GTN 6XX/7XX
1. ON THE ARINC 429 CONFIG PAGE
1. SET IN 1 SPEED TO "LOW"
2. SET IN 1 DATA TO "EFIS FORMAT 2"
3. SET OUT 1 SPEED TO "LOW"
4. SET OUT 1 DATA TO "GARMIN 429" (GTN V6.50 AND LATER)
5. SET OUT 1 DATA TO "GAMA FORMAT 1" WHEN "GARMIN 429" NOT AVAILABLE
6. SET SDI TO "LNAV 1"
2. ON THE RS-232 CONFIG PAGE
1. SET CHNL 3 INPUT TO "MAPMX FORMAT 2" WHEN THIS FORMAT IS AVAILABLE
2. SET CHNL 3 OUTPUT TO "MAPMX" WHEN "MAPMX FORMAT 2" INPUT NOT AVAILABLE
3. SET CHNL 4 INPUT/OUTPUT TO "CONNEXT FORMAT 2" WHEN CONNEXT IS USED
3. ON THE MAIN MAIN INDICATOR (ANALOG) CONFIG PAGE
1. SET SELECTED COURSE FOR VLOC TO "IGNORED"
4. ON THE VOR/LOC/GS ARINC 429 CONFIG PAGE
1. SET NAV RADIO TO "ENABLED"
2. SET TX SPEED TO "LOW"
3. SET SDI TO "VOR/ILS 1"
2. G3X
1. ON THE GDU 4XX/37X RS-232 AND ARINC 429 CONFIG MODE PAGES
1. SET THE CONNECTED GDU 4XX/37X RS-232 CHANNEL TO "MAPMX"
2. SET ARINC 429 TX 1 FORMAT TO "EFIS/AIRDATA FORMAT 1" AND "NAV 1"
3. SET ARINC 429 RX 1 FORMAT TO "GARMIN GPS" AND "NAV 1"
4. SET ARINC 429 RX 2 FORMAT TO "GARMIN VOR/ILS" AND "NAV 1"
2. ON THE GDU 4XX RS-232 CONFIG MODE PAGE WHEN CONNEXT IS USED
1. SET THE CONNECTED GDU 4XX (PFD) RS-232 CHANNEL TO "GTN CONNEXT 2"