Ammeter accuracy and consistency? EI MVP50

[wombat]

The amps on my plane has been quite variable ever since I got it.  It never just holds steady unless the engine isn't running.  Positive to negative, sometimes up to 25 amps.

Here is an example flight and what my ammeter reads during it.    It's basically useless in terms of what the draw or charge is because I can't average these somewhat random values in my head at 3X per second.

 

Does anyone else have similar behavior?

 

[MikeOH]

I would carefully check the wiring (and two fuses) to the shunt.  I don't think you are getting a proper differential reading across the shunt.  I believe the wires are white and green per the EI MVP-50 manual.

 

[Ragsf15e]

2 hours ago, wombat said:

The amps on my plane has been quite variable ever since I got it.  It never just holds steady unless the engine isn't running.  Positive to negative, sometimes up to 25 amps.

Here is an example flight and what my ammeter reads during it.    It's basically useless in terms of what the draw or charge is because I can't average these somewhat random values in my head at 3X per second.

 

Does anyone else have similar behavior?

 

Jeez, I thought mine was noisy with a +\- 1 or 2 amp wiggle, that looks not right.

[ohdub]

Mine does that occasionally. My mechanic cleans/tightens the connections at the master switch and then it's perfectly steady for several months before it goes back to the noisy behaviour.

Steve