PVN3500-S-US Hybrid Inverter/Charger Fault 37

[keithbrainard]

Good Morning,
I am using 2 Solar Hybrid Inverter/chargers, with Grid bypass in a parallel 240V spilt phase configuration. It is a small system intended primarily for my 240 slow start well pump and 2 deep freezers. My PV is wired to only one inverter for my 6-345W Mission Solar panels wired in series/parallel. (2 strings of 3 panels in series, then the 2 strings tied in parallel). Seasonally I have a heater element in the well house and in summer, a small wall mounted AC unit in the shed. I laid the panel out to have the 2 freezers and one leg of the well pump on one line and the seasonal AC/ heater with the other leg of the well pump. I have had an on going, intermittent "Fault code 37 Parallel current sharing fault". I have not set up the inverters for current sharing with the current sharing harness. I have the DB15 cables interfacing the 2 inverters, ONLY. I have induced this fault by loading one line with home radiant heating unit, then inversely loading the opposing out of phase line. Lastly, I drew water from all of my faucets and spigots while the freezer breakers were opened with no additional loads plugged into the system. No issues occurred during that load application. I am fairly convinced the hardware is not the issue. My current resolve was to change the setting # 30 "Model ID setting-Parallel mode needs to be set in the range of 1-6; default 1". Inverter #1 was set to 1 and Inverter #2 was set to 2...I changed #2 to a 1. I also moved the PV to the #2 inverter and assigned it the primary. I witnessed 2-full charge to discharge, entering into bypass then onto full battery cycles with no issues. My question is did I make the correct assumption/ reconfiguration of setting #30 for fixing the fault #37?

 

[FilterGuy]

Can you please post the inverter manual

 

[FilterGuy]

I have not set up the inverters for current sharing with the current sharing harness.

Why not? I would have thought that was required for the parrallel function to work well.

 

[keithbrainard]

I am no SME in this field but the installation manual states not to for parallel spit phase when installing "Two inverters parallel, 1 + 1 system". 1 inverter per line feed. If I was needing to draw more current than a single inverter can put out, I can add 1 more inverter to that leg, that is when the current sharing interface is required. That is designated in the manual as "Three inverters parallel, 2+1 system"

 

[keithbrainard]

See Attachment

 

[FilterGuy]

See Attachment

OK. that makes sense.

 

[FilterGuy]

Could you post the full manual?

What does it say about ""Fault code 37 Parallel current sharing fault"? Strangely, you are having that fault when not doing current sharing.

 

[keithbrainard]

This is all that is referenced in the manual

5. Wiring of Current Sharing Cable
Parallel connection in single phase: Current sharing cable line is the twisted
connection cable. Ensure the “one-in-one out” rule when connecting each
inverter, connect the current sharing cable of the inverter with the current
sharing green port of the inverter to be paralleled(choose one port from the
two, and there is no mandatory sequence requirement). The current sharing
port of the inverter cannot be connected to each other. In addition, make
sure the red and black current sharing connection cable of each inverter are
not manually exchanged. And make sure to tighten the cable with
self-contained screws to avoid the abnormal operation or damage of the
system output caused by abnormal parallel current sharing cable detection.
For specific wiring, please refer to the following diagram.
Parallel Connection in Single Phase

Parallel connection in single phase: The current sharing detection cable of
all inverters connected to the same phased need to be connected together.
But the current sharing detection cable of different phase cannot be joined
together. Other connection precautions are the same as parallel connection
in single phase. For specific wiring please refer to the following diagram.

 

[keithbrainard]

....and YES...they are indicating the fault regardless if it is not even configured to do so!

 

[FilterGuy]

Very strange!! If the re-arrangement of the loads does the trick then I guess you are good to go, but I am afraid I can't help explain what is happening and how the changes would fix it.

 

[keithbrainard]

It's a hanging curve ball and I appreciate your willingness to put some thought to it. I have made 3 attempts to contact the vendor but seem to be left to my own devices. To level set my issue, the fault was intermittent prior to my system being torture tested by the week long polar vortex. I have worked off some self inflicted head wounds with keeping my batteries above freezing and a failed wiring install for the outlet in the well house causing the heater to be off intermittently. Along with moving the PV to the other inverter and assigning it the primary, I did change setting # 30 "Model ID setting-Parallel mode needs to be set in the range of 1-6" under the assumption it is intended for assigning a sequence for additional inverters that may be on one phase. Each one now has the value of 1 in that field. That would be final effort if it ends up failing again. I was looking for a sanity check on my thoughts and actions.