[RE-wrenches] Odd inverter problem

[jay]

HI All,

I’ve got an inverter issue that nobody can fix or figure out. 

Ok some background.
small house, 24v system, 1500watt of PV, midnite CC.
just some lights, entertainment system.
no pumps, fridge etc.

System worked for 4.5 years.

About 6-8 weeks ago customer called and said inverter was off.

I went out, low AC few volts.  tried all the tricks but nothing.
OK dead.  Shipped it off to the repair place here in NorCal.

It needed a total rebuild, cost $800

I installed it, everything worked just fine.
Next day I get a call, its not working.

I go out, yep no AC volts, or again really low 8v.  
try everything, but take it out and send it back.
Its checked, nothing found, another $200

I reinstall the 2nd time.  Works fine, charges etc just like all the other times.
customer calls next day, not working, says his lights are dim. Dim?

I go out, AC is at like 40v.
I take it to my local dealer to send back again.  They of course think I’m crazy at this point.  They put in on their bench, tests fine.  I say, turn it 90 degrees, and lo and behold stops working. And this is with totally different remote, cables etc.

I send it back again.  Test center can’t reproduce the problem.
They get permission for a total rebuild, with “tested” parts.  I cannot confirm if that is new or used., Anyway the OEM approves the replacement boards.

I reinstall, everything works.

I get a call again, not working.  
I go out, yep 8v.  I’ve got video of this now

I call the OEM.  They say not possible really, must be you.  Try it again, do this and this and this.  
So this morning I test it at my house, with new remote, works fine.  I try it vertical again fine.
I drive the hr to the site. install it, doesn’t work, varied from 8-40 v. 
My first clue was dim lights in the house.  

OK so I do a full 15 minute reboot.
Then:
With new remote and cable all other cables removed ( AC and comm wires) except DC +/-.
I get 0v.  
the remote says between 115 and 120v 60 hz.  There is a light buzz coming from the unit, but its not solid, doesn’t sound like a full working inverter.
And every so often, say 30  seconds to 1 min there will be a surge.  I can hear and when it was connected to the house the lights would pulse brighter ( which was a new situation)
But now there is no AC wires attached.
Search mode is off, or on whatever didn’t change anything.

I”ve got a RMA from the OEM.  

But I am just more than stumped.  
You’ll have to figure out what OEM or email me and I’ll tell you.

So at this point, customer is out $1000.
I’m out 5 or 6  trips at 2-3 hours per trip
And its been out of service for like 6-8 weeks, with another few more probably as it is going back to the OEM.

Thoughts, ideas?  

Thanks for your time,

jay