Classic 200 Troubleshooting

[dgd]

F1..

#5 CC is now running Legacy P&O so could you remove it from the follow me loop and then observe if it still does the dropping input voltage to near battery voltage thing.

I would suspect that, for whatever reason, one of the CCs is initiating the input voltage drop and reset cycle and the rest are following it.  Perhaps remove the follow me wiring rather than just disable it in setup or Local App..

dgd

[f1engineering]

The issue is definitely related to the current draw from the inverters.
Drawing a large load out of the batteries will start a cycle for all of the CC's that will continue until we give a hard reboot. They will fall down to near Vbatt, reset, track MPPT for a short time, then fall again.

With small loads, the rate of occurrence drops significantly.

We may disconnect the follow-me cables, but now we'll wait until the tech support from Midnite gives us some input.

I think we're finally going to get a chance to talk to tech support and have them log into our system remotely, so hopefully they'll be able to help us out a bit.

If not, I'm running short on ideas.
FET temp seems reasonable to me, and seems steady.
I still don't get why they would claim this unit can run 3750 Watts if running it above 2/3 capacity triggers errors most of the time.
Still understand that it could be a cable issue though, so maybe I'll check that out, but I don't know how to make it much better given the layout of the rooms I'm working with.

[Westbranch]

I concur with DGD, disconnecting the 'follow me'' links may allow you to identify/isolate the 'guilty-party'.  This problem is definitely out of the norm...

Sorry, I missed the ''follow me '' feature being activated and adding to the diagnosis.

[zoneblue]

In general a classic 150 is rated for 4kW at 48V. Working against you is

a) Cl200s and high vmps, run less efficient. In gerneral 150s are better all round controllers except where your array cable is long.
b) your high ambient. 60C Fet temp is getting up there.

Your 15 feet inverter cables arent ideal, however the drop is only around 0.3V at full rated load, so shouldnt be an issue per se here.

Be careful how you bus those controller outputs. This has previously caused issues for folk that try to put too many amps through busbars that are only rated for 80amps or so.  I would always be crimping 4 guage lugs on the controller outputs (via 80amp breakers) and fixing them to the big carling terminal. So two controllers and one battery positive on the same post. Nice and tight.

But as for the unexpected output, im still struggling to understand whats happening. Maybe some pictures would help.

Couple of other thoughts from rereading:

- 30-40C will impact PV performance, make sure they have plenty of rear ventiliation
- long pv strings, if you have shading, will significantly impact output

Just to be clear are you saying that when the bank is low, and there is full sun, the controllers are not running at near full capacity?

[f1engineering]

Responses:

Follow-Me is disabled on all units.
LoMax is disabled.
i'll work on pictures when I can. Internet is complicated here.

Highest output I have seen from the CC's is 2700 Watts. That may be the highest it can get.
Looking at the panels again, the output is rated 250W@25C, 180W@45C.
So, at 45C, 2700 Watts will be our max. That works to tell me the peak wattage being low.

However, it is still odd to see the performance.
Best description is still:
Unit runs at ~130V parked on MPPT for a while.
Suddenly starts to drop, a few volts at a time, every few seconds.
In about a minute, it will have dropped the whole way to Batt+ voltage.
Then, it resets to Voc and starts a MPPT sweep again.

[f1engineering]

Go to this webpage for pictures.:

http://www.f1engineering.org/?page_id=511

This should help clarify the bus bar situation.
The video is the cycling error that the units display.
Once they hit this mode, they continue to cycle at about 1-2 min intervals until it is reset.

I haven't gotten video of the "OCP" error that triggers this event, as they are random occurances, but after the OCP error (DEFCON 4:FET Drive Error), this cycle continues until we reboot the system.

[dgd]

F1,

Have you tried just using one Classic and see if it does BULK MPPT without the input voltage dropping and resetting issue?
Perhaps power off all the others, radians too so there is just one Classic charging battery bank?
Then perhaps bring each Classic, inverter, online until the problem starts, that way hopefully isolating what triggers the event.

Dgd

[solarj]

Dont know if this would cause a problem but your wizbang jr is upside down. Purple wire should be pointed to - battery side of shunt.