0Volts coming from panels

Vic

Have read every Post in this Thread ...   errrr   meant every Comment in this Discussion,   but,  it does sound like there may be NO Disconnect near the CC to interrupt the PV input to the CC (forget,  exactly).   This is really a must-have item.   DC circuit breakers are very inexpensive,   as would be an appropriate box in which to mount it.  If you do not have this very important item,  please DO install one.

SilverB,   As you know,  pulling a fuse,  with current flowing in the circuit is dangerous and can be damaging to the fuse and fuse holder  --  especially on DC circuits.   If you have a breaker (or disconnect)  at the input to the CC,  and near it,  then the only other reason that there would be current flowing from the PV combiner to that input breaker when it is open,  would be due to a short in the cable between the Combiner and that breaker.

Know that you do have a Magnum inverter,   but make certain that the Magnum HV CC will accommodate your needs.   IIRC the Magnum CC needs several optional widgets that will allow you to set the needed custom battery charge profiles.   Think that you need a certain type of Remote,  and perhaps a Communication box thingie,  some cables,   etc.   These added items might make that HV CC more expensive than other available options.

Thanks for checking the Max Voc.   Thought that there was a Log entry for the all-time Max Voc.

It is possible that opening the battery breaker while the CC was producing power might have caused some transient,   that could have damaged the CC,  especially if the Vin was running very close to the Vin Maximum.   Believe that the FM CCs cease operation at 145 V at the input ...

FWIW,   Vic

SilverB

Agreed, I removed the lightning arrestor with no change, so at this point Im thinking the CC is toast, going to investigate more tonight/this weekend. The only other thing between the panels and the CC is the combiner box, which I had open last night to remove the arrestor, and nothing looked burnt or odd.