Earth Fault Alarm on Sunny Boy

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ATSman

ATSman
Location
San Francisco Bay Area
Occupation
Electrical Engineer/ Electrical Testing & Controls
I have residential installation with 2 PV arrays feeding 2 separate Sonny Boy SWR2500U
inverters. One of the inverters is showing the red LED Earth Fault (GF) preventing
power output. Manual states that with only red LED lit, the GFDI fuse is blown; if red
and yellow LED lit then indicates actual GF. Fuse checks good. The display
shows the normal diagnostics sequence when powered up or powered down. The
source voltages show in normal range: 322VDC, 240VAC.
I lifted the ground wire off the inverter frame coming from the array and powered up
unit and still get the red GF LED. With this wire lifted how can there be GF current flow?
There is a separate GFDI sensing board that sends
the signal to light the red LED on a GF. I suspect this board is bad. Has anyone worked
on this particular inverter and can shed some light?
Thanks in advance.
 

Canton

Senior Member
Location
Virginia
Occupation
Electrician
I have residential installation with 2 PV arrays feeding 2 separate Sonny Boy SWR2500U
inverters. One of the inverters is showing the red LED Earth Fault (GF) preventing
power output. Manual states that with only red LED lit, the GFDI fuse is blown; if red
and yellow LED lit then indicates actual GF. Fuse checks good. The display
shows the normal diagnostics sequence when powered up or powered down. The
source voltages show in normal range: 322VDC, 240VAC.
I lifted the ground wire off the inverter frame coming from the array and powered up
unit and still get the red GF LED. With this wire lifted how can there be GF current flow?
There is a separate GFDI sensing board that sends
the signal to light the red LED on a GF. I suspect this board is bad. Has anyone worked
on this particular inverter and can shed some light?
Thanks in advance.

I'll let you know on Friday. I don't have all the details but I'm installing a Sonny boy model, one with the standby 120 volt receptacle when grid is down.
 

Zee

Senior Member
Location
CA
I'll let you know on Friday. I don't have all the details but I'm installing a Sonny boy model, one with the standby 120 volt receptacle when grid is down.

Given my experiences with these inverters, i am 90% sure you need a replacement.
(although i never work inside teh electronics on an inverter...... i do not know enough about teh electronics, and sunny boy usually will not service these old ones)
Given the red color that indicates their age, the warranty expired years ago..... 5 yr wrrty.
Likely 10 year old inverter.

If the red is lit then - I BELEIVE - it will remain lit, fault or not, until a new fuse is installed. Fuse must be 600 VDC!

If you are 'lucky" it will actually be an array ground fault and not an inverter problem.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
If the fuse is testing good then probably the internal circuit that tests the fuse has gone bad.

I agree with Zee. This inverter has probably lasted about as long as it could have been expected to, and the best remedy is probably a new inverter with a 10 or 15 year warranty. My understanding is that SMA no longer services these inverters, and fixing it is probably all around more expensive than buying a new model.
 

ATSman

ATSman
Location
San Francisco Bay Area
Occupation
Electrical Engineer/ Electrical Testing & Controls
GFDI Circuit Board

GFDI Circuit Board

FYI all,
My suspicion was correct.
After doing some research on you tube and talking with some solar guru's
I solved the problem with the Sunny Boy. The GFDI ground detection circuit board was replaced with the one in the second unit and the error went away. The defective board was indicating a ground fault and preventing power output.
Turns out this is a common problem with these units as indicated by the attached thread.

The PDF file for the spec on the GFDI chip was too big to upload. Just google
"SMA Sensitec CMS2005.pdf "to find it.
 

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Zee

Senior Member
Location
CA
That is great.

I wonder how long you can keep these running!

So, you did a temporary swap of the GFDI board? Could you get a new and permanent replacement?
edit: Oh I see your attachment, you did and you have xtras....nice!
 
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