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Old 04-09-2019, 11:38 AM
NinerBikes NinerBikes is offline
Join Date: Dec 2018
Location: Granada Hills
Posts: 186

Originally Posted by Mich48041 View Post
I never thought to read between the lines like Mike Miller did. So is the problem actually a low voltage problem and not an ammeter problem?
If so and this RV-12 has Van's original control board, then a burned circuit board trace will result in no voltage on regulator terminal C. There is no fuse protecting the terminal "C" wire. If that wire shorts to ground, even for a second, the control board will be damaged. Some people elect not to have the control board repaired. Instead, they jumper regulator terminals "B" and "C" together. The disadvantage to doing that is that it will not be possible to shut off electrical power if there is smoke in the cockpit, unless the engine is stopped.
If you have any ham radio clubs with old ham radio operators in it nearby, they could open it up, and look at the circuit board traces with a jewelers loupe, and make a lead in with a fuse, or just replace the broken trace. Takes some good soldering work with a repair adjustable temp soldering iron to do it, but it's not too difficult.
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Old 04-09-2019, 02:04 PM
Pdtofly Pdtofly is offline
Join Date: Jan 2012
Location: Reno, NV
Posts: 256
Default Send me an email

Originally Posted by NinerBikes View Post
Anyone have an idea what it would cost to replace a D-180 with a Skyview D1000 Touch, with GPS 2020 receive antenna, on an older RV-12, pre 2013 finish build date?

Send me an email at, and I can get that info.

There is a post earlier today that has a couple year old NIB D1000 Touch for $2800. The GPS-2020 costs $590, and you would need the EMS box which costs $600, unless you have a D120 installed.

I think Vans has a pre made wiring harness that will convert the RV-12 D-100 to SkyView.


Last edited by Pdtofly : 04-09-2019 at 02:17 PM.
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Old 04-09-2019, 04:01 PM
pilotyoung pilotyoung is online now
Join Date: Jan 2018
Location: Birmingham, AL
Posts: 124
Default 912 ULS Ammeter


Thanks for the information. Mine is the newer version with the Skyview and the switch module in the middle of the panel at the bottom. So I presume it has a fuse.

John D. Young, RV-12 Owner
Serial Number 120022, N6812Y
Bought it as a flying airplane in Feb. 2018
Just passed 140 hours flight time in RV-12, and 10,000 hours mostly in corporate jets. I am a CFI; CFII; MEI; and a advancd Ground Instructor, CFIG; and hoping to be able to help new RV-12 owners by doing some transition training for new builders and owners in RV-12's.
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Old 04-09-2019, 04:11 PM
Aggie78 Aggie78 is offline
Join Date: May 2014
Location: Fort Worth, Texas
Posts: 410

Originally Posted by jaybhansen View Post
The ammeter is my RV12 shows a negative reading. I understand that the two battery wires can be interchanged. Also the two generator wires. I have tried any combination on my current and a new rectifier and get the same results. Any advice would be appreciated.
When I bought my already-flying RV-7, I noticed the same thing on my Skyview system. System was keeping the battery charged, but showed a discharge when the engine ran but positive current when the it wasn't...

I found the amp shunt under the panel and reversed the two small "sense" wires located on it. Apparently, the original builder just had them reversed.

That made the indications normalize and all good now in the ~400 hours since...

Obvious it showing a discharge but is the system keeping the battery charged?

If so, perhaps go looking for the shunt...

Edited to add:

Skyview System Install Guide V15.3 Page 7-62 has a detailed description. Install guide found on Dynon's website.
Rob Schroer
T67-Hicks Airport, Texas
VAF Monthly Donor

Last edited by Aggie78 : 04-09-2019 at 04:17 PM.
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Old 04-09-2019, 09:07 PM
Mich48041 Mich48041 is offline
Join Date: Apr 2008
Location: Riley TWP MI
Posts: 2,886

Regardless of what the ammeter says, if electrical system voltage is 13 or
greater, the battery is not being discharged. If system voltage is 13.8 or
greater, the battery is being charged.
Joe Gores
RV-12 Flying
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Old 04-12-2019, 09:27 AM
MMiller MMiller is offline
Join Date: Oct 2010
Location: Babylon NY
Posts: 52

David and Joe are correct with their comments regarding the charging system. This is intended to expand on those comments.

When the 912ULS is providing electrical power, the DC ammeter is measuring an AC current flowing through the shunt. The Rotax stator is a single phase coil. In a single phase system the voltage crosses zero twice each cycle, this generates a discontinuous output current. This results in a consumer load current that has two components, an alternator component and a battery component. When two supplies are connected in parallel, the supply with the higher voltage provides the current. The rectifier will supply the load current until the rectified voltage drops below battery voltage. The battery will provide load current during the time period the rectified voltage is lower than battery voltage. This happens between 300 and 950 times per second depending on engine RPM.

This is not an issue with the typical three phase alternator because phase overlap allows for a continuous output current.

Here is a link to full size copy;

Last edited by MMiller : 08-01-2019 at 09:19 AM.
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