Solar string shows Voltage but no current

[BenS]

Hi,

 

I have a Sunsynk 8kW inverter with 10 x 550W JA solar panels arranged in 2 strings of 5 each which was installed 15 months ago. This past Friday afternoon the one string (MPPT2) stopped feeding power to the inverter. I only realised this yesterday after noticing the reduced solar production and checking the Sunsynk and SolarAssistant apps. MPPT2 is showing a voltage reading but no current. I received no warnings or errors via the Sunsynk app.

 

Has anyone experienced something similar?

[Arandoza]

Your MPPT 2 voltage appears insanely low 1-4volts ? which maybe a indication of an open circuit or possibly a failed MPPT controller? The 1-4 volts being a sensing voltage ? thats being shown?

Have you checked the second strings MC4 connectors are all still properly connected, none that are melted or deformed? and properly inserted into each other? If you have a PV disconnect switch? is it ok? etc.

Have had it once or twice where MC4 connectors deformed and melted over time and still got a good voltage but would not produce any amps, only upon inspection did we find the problem of the MC4 connectors having melted probably due to to arcing inside the mated connectors?

Could also be a damaged PV cable to/from the string? or rats or similar chewing thru the pv cable?

[BenS]

Thanks. I notified the installer to come and have a look. I will give feedback once the cause is know.

If it is indeed a failed MPPT controller, I hope the Sunsynk warranty will cover the repairs.

Edited July 8 by BenS

[P1000]

Check the fuse.

[BenS]

You called it. Fuse for sting 2 was blown.