Ammeter fluctuation at high RPM

[casimiroj]

Hi all.

My Dynon EMS 120 shows Amps fluctuation at high RPM (actually an RPM different than stand-by). From positive readings to negative randomly.

Before switching on the engine, it works (checked with a fluke amp meter). After switching on the engine, while warming up the engine, also works.

But after take-off during climb and cruise, the values are wrong.

I have checked some posts in the past without success.

Thanks!

 

[dynonsupport]

Rotax engine? If so, their generators are noisy, which makes getting a stable ammeter reading hard for the D120. We don't currently have a solution to this issue.

 

[casimiroj]

Rotax engine? If so, their generators are noisy, which makes getting a stable ammeter reading hard for the D120. We don't currently have a solution to this issue.

No, it is Jabiru 3300. The thing is that while stopped and low RPM, the values are ok. At cruise, goes from + to - cycling.

 

[dynonsupport]

Jake - if you're reading - I seem to remember you've seen this in the past in your installation experience, but I can't find the thread. Any thoughts on this?

 

[casimiroj]

Jake - if you're reading - I seem to remember you've seen this in the past in your installation experience, but I can't find the thread. Any thoughts on this?

I also seem to remember this issue (or a similar one) here in the forum, but i cannot find it in the history.

 

[jakej]

Casi

I'd be checking your power (& regulator ground) wires, ie how well they are crimped & security of the wires on amp shunt etc - these 'fluctuations' are usually caused by inadequately secured connections.  No offence meant.  

FWIW - while I'm on the subject of electrical connections re Jabiru engines - I usually cut off the supplied/installed 'push-on' terminals on the Alternator wires.  IMO they are of poor quality as the metal (bare brass) is very thin and doesn't give a solid connection like the AMP types do.

You can feel the 'lightness' of the joint and sometimes there will be some blackening of the insulation caused by high resistance.

HTH

Jake J

 

[jaba-who]

I can echo Jake's experience on this topic and advise you check all your connections.
I have a D 180 and a Jabiru 3300 and was getting similar fluctuations in my readings.  (It may have been my thread you guys can remember as I posted it and Jake gave me the clue to solving it)

I finally tracked the problem down to the cheap fuse holder in the Amps high line.  (I have one in each amps sensor wire as per the installation instructions)
Once I ditched the cheap fuse holders and got some better quality panel mounted ones the problem went away.

 

[casimiroj]

Ok, i'll try these tips (check connectors and cheap fuseholders)