What's new
Van's Air Force

The definitive Van's Aircraft support community! Buying, building or flying an RV? Join our exclusive family of mentors and enthusiasts!

RV12is electrical help?

H

hughfi

Well Known Member
Hi there folks,

I am just finishing up my RV12is build and finishing the avionics installation. I have the IFR panel with the GTN650 and dual G3x screens. I am looking for some help isolating some electrical gremlins from anyone who may have built an RV12is?

I am having some unusual electrical readings on the G3x and want to know if someone else who has built one may have had something similar.

1.) When the engine is turned off, but master on, I see 13.2 volts on the voltmeter bar, and 14.1v on the 'EFIS BATT V'. That seems high to me when there is no alternator running? Is this correct?

2.) More concerning is that my AMP meter on the screen is showing 0 at all times even with the engine running, and also my 'Battery Amps' is showing -1.

When I start the engine the voltmeter rises to 13.7 volts which tells me the alternator is doing something (I think), but the AMP meter still shows 0, and the battery voltage continues to show -1 for a while. After running the engine for about 20 mins, the battery voltage went to 0 instead of -1.

I am trying to determine if a.) My alternator is working b.) Why I am not seeing any AMP draw even when I turn on lights, fuel pumps etc.. and c.) why my battery voltage reads low at -1.

Any thoughts or advice would be greatly appreciated.

Thanks,

Hugh
 
If you have the 912iS, it has two generators. In order to get generator B to power the main bus you must increase the RPM to 2500 for 5 seconds. When that happens you will notice the amps increase quite a bit as the battery begins to charge.

If you already know this or you have a 912ULS, then I'm not sure what is going on.

If you don't know this and you do have a 912iS, then I suggest rereading the electrical sections in the POH and the FTS.

Hope it is as simple as that. :)
.
 
The volts reading kind of "depends" -- what is EFIS BATT V connected to in your system? If it's the TCW-IBBS-12-6ah, then 14.1V or so sounds about right.

The erroneous amps reading could be caused by the GEA 24 wires being swapped at the shunt.

Good Luck!
 
Update on this.

I have isolated that after 2500 rpms for 5 seconds, I can suddenly see the volts rising from 13.1 up to 13.8 which I guess confirms the alternator is working. I will take a look at the shunt wires going into the GEA 24 to see if thats the problem with the AMP meter still staying at 0 no matter what I do. I also see the battery volts continue to stay at 0.
 
hughfi said:
Update on this.

I have isolated that after 2500 rpms for 5 seconds, I can suddenly see the volts rising from 13.1 up to 13.8 which I guess confirms the alternator is working. I will take a look at the shunt wires going into the GEA 24 to see if thats the problem with the AMP meter still staying at 0 no matter what I do. I also see the battery volts continue to stay at 0.
Click to expand...
Make sure your gounds are properly grounded. Had one that showed a zeroc to negative amperage and positive voltage...bad ground!
 
hughfi said:
Update on this.

I have isolated that after 2500 rpms for 5 seconds, I can suddenly see the volts rising from 13.1 up to 13.8 which I guess confirms the alternator is working. I will take a look at the shunt wires going into the GEA 24 to see if thats the problem with the AMP meter still staying at 0 no matter what I do. I also see the battery volts continue to stay at 0.
Click to expand...
KAI Page 42MiS/U-14, Figure 2. Double check the K7028, K7023, and K7033 wiring. Look at the X3 Connector housing with a magnifying glass to make sure you understand the numbering 1,2 and 3. Its easy to install the K7028 and K7023 in the wrong slot.
 
philcam said:
KAI Page 42MiS/U-14, Figure 2. Double check the K7028, K7023, and K7033 wiring. Look at the X3 Connector housing with a magnifying glass to make sure you understand the numbering 1,2 and 3. Its easy to install the K7028 and K7023 in the wrong slot.
Click to expand...
Agree to check this connector. I had to split apart and redo mine 3 times before I got it correct during initial installation!
 
You must log in or register to reply here.
Back
Top