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Old 09-22-2020, 06:06 PM
cardinalflier cardinalflier is offline
Join Date: Jul 2015
Location: Granite Bay, Ca
Posts: 131
Default Huge discharge showing on my Dynon

Yesterday, in the run up area, I noticed a 4-5 amp negative discharge showing on my Dynon Skyview that I installed 3.5 years ago in my RV6. Back at my hangar, I started checking simple connections, starting at the alternator. The only thing I found was a snug, not tight, but not very loose positive battery cableconnection at the battery ( an Odysse 680). I tightened the connection, fired up, and everything read normal. Today, I got a negative 55 amp reading, with the engine running or not running, but with the master turned on. No smoke, no fire, no hot wires, no popped circuit breakers, no obvious clues. Any thoughts as to where to start trouble shooting. Battery is 3 years old and the Plane Power alternator is about 3.5 years old. Do the Dynon shunts go bad? Thanks in advance for any and all suggestions.
Bruce Estes
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Old 09-22-2020, 06:30 PM
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airguy airguy is offline
Join Date: Oct 2006
Location: Garden City, Tx
Posts: 5,312

The shunt reads current going through it by a voltage drop across the bar. 1 millivolt of voltage drop equals 1 amp of current.

You could start by using a good digital voltmeter, turning on the system and putting the test leads on the top and bottom connections of the shunt, and measuring the voltage drop across the shunt directly instead of relying on what the EMS is reporting. That will tell you, for real, how much current is going through the shunt and let you start troubleshooting what is really going on.

If your alternator stator or diode pack is shorted, the 55 amp draw is possible from that source.
Greg Niehues - SEL, IFR, Repairman Cert.
Garden City, TX VAF 2021 dues paid
N16GN flying 750 hrs and counting; IO360, SDS, WWRV200, Dynon HDX, IFD440
Built an off-plan RV9A with too much fuel and too much HP. Should drop dead any minute now.
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Old 09-22-2020, 06:32 PM
Mich48041 Mich48041 is offline
Join Date: Apr 2008
Location: Riley TWP MI
Posts: 3,141

Shunts do go bad. But more likely is a bad connection on the shunt.
Remove all terminals from the shunt, clean and reconnect.
Joe Gores
RV-12 Flying
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Old 09-23-2020, 02:45 PM
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GalinHdz GalinHdz is offline
Join Date: Mar 2010
Location: KSGJ / TJBQ
Posts: 2,126

Originally Posted by Mich48041 View Post
Shunts do go bad. But more likely is a bad connection on the shunt.
Remove all terminals from the shunt, clean and reconnect.
Adding to this, the most common culprit, in your scenario, is that one of the small wires from the shunt to the SkyView is either loose or dirty. Make sure these connections are good from the shunt all the way to the DB37 plug on theSkyView EMS module.

FCC Radiotelephone (PG) with Radar Endorsement
2020 Donation made
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