For many months now Array-C has been operating well, but that all changed when the ice showed up. We had ice form and stick around for weeks. And when it started thawing I noticed a problem with one of my solar strings. It was throwing an error called "DC_Insulation_Fault". Looking up the error, its caused by moisture entering the solar panel wires and touching the grounded frame of the panels.
I started my mining rigs as I usually do in the morning, but noticed the solar input was much lower than expected. About half of what it should be for how sunny it was and the time of day. At the time of this error, the sun was just coming up. And it was very snowy outside. Not wanting to deal with hundreds of volts in DC in the melting snow and ice. I waited until night time to switch it off for my own safety. Even though my arrays are grounded, I would rather not test it with myself.. lol
We can see on the left side of the screen, it tells us the solar input. M1 is doing good, producing lots of power. But M2 was cut off by the inverter. It was producing strange voltages and the inverter detected an issue with the resistance and shut it off for safety.
Looking at the event history for this inverter, had some other issues previously but nothing that stopped it from working such as the DC_Insulation_Fault error. Honestly those other errors I did not notice until I was troubleshooting the issue at hand. Guess the unit just reboot and resolved the issues on its own. The overcurrent fault I am not sure what happened, but the voltlow errors was related to the battery getting too low, and only the solar panels were producing power that morning. And probably some clouds got in the way for a moment causing the solar panel voltage to drop too much. Not an issue when the batteries are charged. But before I added the second battery bank, I had a few times I drained the banks.
Above is the day before the insulation fault. All looks good, but at night seems like the inverter started to have troubles reading the voltage on that blue line. As points had a near constant reading. Normally it varies constantly.
The next day, we could really see the issue occur. The two strings fell out of sync, compared to the day before they were nearly in line to each other. At night time we can see the voltage does not change at all as well. The blue line is the troublemaker.
Next day it started acting up again, so I cut off the disconnect switch on the inverter inside the building. And waited for night fall to turn off by the panels.
Once the snow melted and the ice was gone, I waited until nightfall again to minimize the dangers and worked on the broken string. I inspected the connectors inside the disconnect box, all looked fine. And walked down the row for this string. My concern came to noticing that my home run wire was tied to the metal ground mount frame. I think the ice bridged the connection, water got inside the connector and the ice made it bridge to the frame. Causing the inverter to detect an abnormal resistance reading causing the fault. I moved the wire to the wooden frame, isolating it from the metal frame. I did it on both ends of the home run wires as they were both touching the frame.
With the issue resolved, I started up the both strings again. And sure enough we had both strings running well after.
Now their voltages are so close, you cannot even see them on the chart as two. As it should be, they are identical strings.. Same panel amounts.
As of today, all is working well. Still cloudy but hopefully soon I will get a fully sunny day and get around 3500w out of each string. Cant wait to get that third string up and running.
Really glad to have this ground mount system, as if I had this issue on a roof mount. I would have had to climb up on the roof to resolve. So I am happy with my ground mount system, making it much easier to work on them.
