G3X Touch - Ammeter Mysteries

[AlexPeterson]

I've had the G3X Touch over 7 years, and all has worked flawlessly save for the ammeter.

About 3 years ago I got a zero amps warning which I knew was not true since the voltages indicated charging levels to the battery (~14v). Over the next few dozen flights I got several more, almost always during the taxi out. They always cleared somewhere between 10 and 30s after onset. Voltages always steady. This happened once in every 5 or ten flights, again only occurring on taxi out but once in-flight that I recall. After the first few incidences, I inspected and tugged on the wires, but found nothing amiss. I had simply decided to ignore it until/if such time it persisted enough where I could track it down.

Yesterday a new piece of evidence presented itself. Shortly after startup, but this time before taxi-out, I got the zero amp alarm and indication. However, it was shortly followed by the big X through the amp reading as though the GEA-24 simply wasn't sending any signal regarding the ammeter to the G3X Touch. This also cleared itself within 20 or 30 seconds and functioned as normal the remainder of the flight. All the other engine instruments remained fully functional.

Any thoughts?

 

[dmattmul]

Type and manufacture of sending unit, shunt or hall effect sensor? If hall effect replace donut. They are more prone to failure.

 

[ronrapp]

I've had the G3X Touch over 7 years, and all has worked flawlessly save for the ammeter.

About 3 years ago I got a zero amps warning which I knew was not true since the voltages indicated charging levels to the battery (~14v). Over the next few dozen flights I got several more, almost always during the taxi out. They always cleared somewhere between 10 and 30s after onset. Voltages always steady. This happened once in every 5 or ten flights, again only occurring on taxi out but once in-flight that I recall. After the first few incidences, I inspected and tugged on the wires, but found nothing amiss. I had simply decided to ignore it until/if such time it persisted enough where I could track it down.

Yesterday a new piece of evidence presented itself. Shortly after startup, but this time before taxi-out, I got the zero amp alarm and indication. However, it was shortly followed by the big X through the amp reading as though the GEA-24 simply wasn't sending any signal regarding the ammeter to the G3X Touch. This also cleared itself within 20 or 30 seconds and functioned as normal the remainder of the flight. All the other engine instruments remained fully functional.

Any thoughts?

I've heard of others having this kind of issue. In fact, I had something similar on my G3X. Never got the red X through the ammeter, but I'd see big spikes and drops in the ammeter reading when charting the engine data after a flight. Turns out it was a problem with the shunt. After reviewing a number of log files, I realized there was a correspondence between the ammeter issue and the phase of flight. Which is to say, the shunt issue was vibration-related.

--Ron