Fronius Error 523


I have a question, My system has 2 MPPT Strings, North east array 11 panels and a north west array with 9 panels Jinko 330 watt.

I noticed that north east MPPT 2 DC power shows 0. and I got error 523 on fronius Inverter. Any reasons for that?

I have 20x Jinko 330w Panels and fronius 5kw inverter .


That’s a low voltage fault code:

DC2 Input Voltage too low
The DC voltage on input 2 of the inverter is too low
Check voltage & polarity on input 2 of the inverter. Check MPP settings / voltage at the “Installer Menu Basic”. If this STATE code keeps recurring please contact your solar power system installer.

Looking at the chart it shows MPP2 voltage < 80V, and that’s too low for the system to generate power. Something isn’t right. An 11 panel array should have a DC voltage in the 350V range give or take.

I suggest a call to your installer to assist with finding and rectifying the fault.


hi please do a manual restart of your inverter,the dc2 string solenoid in the inverter may have failed to close on inverter start up for the day, when the inverter starts you should here too clicks that,s the output solenoids closing, also the 70 volts DC you are seeing is only the ground background voltage in the inverter, NOT partial output from your panels,if the restart do,s not fix it the its probably a MC4 connector failure between the panels that is your problem ,and to get that fixed you need your system installer on site to fix it for you.Jim


Thank you!


Did it work?


I did restart . Still Same. Contacted with the installer to fix it.


Nope. Waiting for the Installer.


All Good Now


What was it?


MPPT 2 polarity controler was off.


Do you know why it was off or went off?