Xantrex MS2000 Charging Issues

[jerryk]

I have a Xantrex MS2000 Inverter/Charger that was given me because of charging issues.  I have gone through it and can't find any obvious faults with the following exception.  The charging output has a significant ac component as shown in attached photo.  The inverter output is a very clean sine wave.  It's a difficult board to test since it has conformal coating on all of the boards and is three layered.

I assume this is not normal for an Inverter/Charger like this to have such a dirty charging output, however it seems to be charging the batteries fine as far as I can tell.

Any ideas on how to trouble shoot this problem?

I added a photo of the component boards (less the two inverter boards) if this helps.

Thanks - Jerry

[jerryk]

I'm finally at the point of finishing off this project.  I think I got to the bottom of the charging complaint that caused a friend to will his inverter to me.  He said it would not charge the batteries in his boat at all and went to fault. I managed to get it to fault only once and then the problem went away.  There was a 1% sense resistor at the ac detect transformer that was off by 40% so I replaced it.  So far I have ran it through all the trials I can think of in both the AC/Charge mode and the inverter mode without any fault codes or warnings being generated.  I replaced most of the ceramic y-caps on the charger and ac filter board since I had it apart.

But I still get that AC ripple in the photo above.

It's about a 2V ripple at 60hz only in charge mode.  This is measured at the main battery lugs on the inverter.  Is this just normal on inverter/chargers like this?  I ask this because in the mean time I did some repair/learning on a Magnasine 2810 that was flooded with salt water ( covered in a thread on Beginners Forum).  The Magnasine now works fine other than it too has a fair bit of ripple (1V) on the charging output.

So is this kind of ripple normal on inverter/chargers?  Both have very large DC filter banks.  The Xantrex MS2000 uses a separate DC filter board with 4 groups of 5 4700UF caps and the Magnasine MS2810 has four 6800UF caps in the middle of the FET board.  In both cases the inverted AC looks like a very nice sine wave.

If I never looked at the DC charging output on my oscilloscope I would be happy with the results.  Am I worried for no good reason?

Jerry