| Confirmed! Reading the same points on a different inverter yielded the same results. At a different site, I measured -188.8VDC to ground on both L1 and L2.
My suspicion is that there’s leakage current via the H-bridge output. Just a thought.
Case closed, thanks.
Rick Brown Solshine Energy Solar Electric Contracting Services www.solshineenergy.com Roanoke, VA Office: 540.235.3095 Mobile: 540.808.9502
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On Oct 16, 2024, at 3:49 PM, r...@solshineenergy.com wrote:
Sorry I wasn’t clear. There’s no PV tied directly to the Sol-Ark however the Sunny Boy has 5.52 kW of PV. Again the SB is AC coupled to the Sol-Ark via its Load input/output.
I can assure you that the DC is not coming from an external source. There are no faults at either inverter (measured or indicated by the inverter(s)). Both systems are operating normally.
I’ll be looking at another site to verify whether these readings are consistent or an anomaly.
Thanks, Rick On Oct 15, 2024, at 3:49 PM, William Miller via RE-wrenches <re-wrenches@lists.re-wrenches.org> wrote:
Rick: Two questions: 1. If you don’t have PV on this system, what are those glassy, flat things on the roof wired to the DC inputs of your Sunny Boy? 2. Think to yourself: What component(s) on this project could possibly produce high voltage DC? I think the answer to both questions is… PV panels. I highly suspect you have a PV ground fault. Proceed with caution. On the Sunny Boy I would check the DC voltage between L1 and ground, between L2 and ground and between neutral and ground. Do this in the operational configuration that is producing the DC voltage on the Gen inputs. While you are at it, check DC voltages between the Sunny Boy DC inputs to ground and between the Sunny Boy Chassis and ground. Check your GEC, GEC bonding conductor and all of the system EGCs. I would also check the GFDI fuse on the Sunny Boy. William Miller Miller Solar 17395 Oak Road, Atascadero, CA 93422 805-438-5600 CA Lic. 773985 William, There’s no PV on this system. It’s AC coupled to an SMA SB5.0. As a test, we turned off the Grid input, Load output, and turned off the battery breaker. As expected, the high voltage DC eventually bled to 0V. Turning things on in this order: Battery, Grid, then Load resulted in the high voltage appearing once the Grid relay kicked on. Actually, the high voltage ramped up slowly once the Grid relay turned on. We’ve been installing these for years and have never seen this. Then again, we’ve never measured that point.
If I had to guess I’d say you have a PV wiring fault. The PV positive may be shorted to ground.
This would make the inverter chassis negative in relation to ground. The logic I use is to ask what is the likely source of DC at 195 volts? It is most likely the PV circuits, wouldn’t you say? If the DC Fault is not eternal then it must be internal to the inverter. This could be a dangerous situation. I would proceed with caution. Try completely isolating the PV from the inverter as a start. 17395 Oak Road, Atascadero, CA 93422 Back on the Sol-Ark topic again. We have a customer whose 12kW is measuring -195VDC to ground from L1 and L2 with the Gen breaker open. L1 to L2 = 0V. I know the Gen input can be configured as an output, but reading a high DC voltage to ground is concerning. The generator has never been run. System is operating normally. Anyone have a Sol-Ark accessible that could verify what they’re reading? Solar Electric Contracting Services CONFIDENTIALITY NOTICE -- This email is intended only for the person(s) named in the message header. Unless otherwise indicated, it contains information that is confidential, privileged and/or exempt from disclosure under applicable law. If you have received this message in error, please notify the sender of the error and delete the message. Thank you. rick brown
SolShine Energy Alternatives, LLC
Electrical & Solar Contracting Services
www.SolShineEnergy.com
Roanoke, VA Office: 540.235.3095
Mobile: 540.808.9502
VA Class A Contractor Lic# 2705147660
VA Master Electrician Lic# 2710062762
VA Alternative Energy Systems Installer
NABCEP Certified PV Installation Professional 110112-21
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rick brown
SolShine Energy Alternatives, LLC
Electrical & Solar Contracting Services
www.SolShineEnergy.com
Roanoke, VA Office: 540.235.3095
Mobile: 540.808.9502
VA Class A Contractor Lic# 2705147660
VA Master Electrician Lic# 2710062762
VA Alternative Energy Systems Installer
NABCEP Certified PV Installation Professional 110112-21
the message header. Unless otherwise indicated, it contains information that is
confidential, privileged and/or exempt from disclosure under applicable law. If you have
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message. Thank you.”
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