Mangum PT100 error F09 (Internal Phase Fault)

Katherine

I had a 24V off grid system installed last fall and have repeating F09 errors which clear after a few seconds. My installer has tried several things to fix it (first of all installing a new PT 100 from Mangum, which did not fix the problem). Mangum has offered suggestions but nothing has worked and wondering if any of you might have some insight. Here are system details:

8 285 watt modules on pole about 200 feet from the house, run underground in pvc conduit

Magnum MS4024 PAE inverter/charger  and Mangum PT 100 controller

4 @ ROLLS 6CS25P lead acid batteries 

Installer has replaced the fuses at the panels, disconnected the power surge protector at the panels temporarily, rerun the ground wire at the house to make it agree exactly to the Mangum diagram, replaced the PV breaker, checked all connections. Still faults.

The situation that creates the faults is where the watt output from the panels increases abruptly. Examples: a cold cloudy/sunny day where it goes from 300 watts to 2200 watts as a cloud clears. Or when in float but I turn on something in the house that draws 1500 watts and the panel output shoots up from 200 watts to 1700 watts.

The good but weird thing is the fault clears itself - according to the manual it is a fault that should have to be reset. Here is the fault description "The PT controller turned off to help protect itself because one or more of the internal phases is faulty, or the phase signals are not in sync with each other."

Any suggestions on what might be causing this?

Estragon

Can you post the Vmp and Voc specs for the panels, and if you know, how wired (2 in series?)

The symptoms sound more like a pv overvoltage, which tend to happen on cold broken cloudy days, and within reason will self-clear (I think Magnum has a grace zone much like Midnite "hypervoc").

Katherine

Panels are 2 X 4 in series and then paralleled.

Vmp 127.6V Voc 156.4V  (not sure what this means but copied from an email to Mangum from installer)

mcgivor

The VOC is listed is at 20°C, at cooler temperatures it increases, so probably the voltage has exceed the maximum allowable, I believe Outback has a string calculator which Witt determine the optimum arrangement and includes temperature in the calculation.

Katherine

Thanks for that info - we've been having this problem in hot or cold weather though, since Sept so thinking it isn't temperature related.

mcgivor

Just checked the specs, the maximum input of the PT 100 is 240V, so unlikely the problem.

Estragon

According to the manual I have, it looks like the controller soft faults at ~ 187v pv string input. I assume the Voc of 156.4 is string Voc (4 panels in series? - as per panel specs, not measured), and that the installer sent this to Magnum suggests they're already considering this as a possible contributing factor.

Aside from temperature, wire size & length could be a factor. With low current, voltage will be higher than with higher current.

Are there any coils of extra wire between the array and controller, or controller and bank?

I'm not sure what "phase signals" the controller is indicating a fault with, so it might be best to let the installer keep working with Magnum for now to get it sorted. Maybe a bug in the mppt algo or exceptions handling in firmware? It does read like it should be a fault requiring a reset.

Please post as things develop.

Katherine

Thanks for those ideas, I'll pass on to installer. I do know there are no extra coils of wire between the array and controller and the controller and bank (which are only about 2 feet apart)

Estragon

One other thought; are there any other wires (eg inverter AC outputs) run in the same conduit as, or otherwise parallel to DC wire?

I'm wondering about this (or coiled wire) resulting in magnetic fields generated when current flow increases and making things "interesting".

Dave Angelini

This is a warranty problem and it is good that you have one. Get them to replace the charger or fix it.

Katherine

Thanks Estragon I will check on that also but I don't think so.