Running out of power - Resting

[off-grid-geeks]

Midnite classic 200
2054:08/11/2015
2079:11/23/2015

Running flawlessly past 4 years.
No changes to any part of the system.

Full sun today, 24 volt 460 AH battery bank started day at 84%
Classic shows 67 volts coming in from panels (4P2S) 2120W array.

But zero amps, display shows classic is resting, reason code 1 (Low Light).
All 8 panels fully illuminated.

Did a new day reset, still resting.
Did a power cycle, still resting.

Disconnected panels, watched display drop from 67 volts to about 13 volts.
Reconnected panels, and immediately went into BULK at 59 amps to battery, around 1600 watts coming in.
Lasted about 15 minutes, now back to resting, 67 volts, zero amps, zero watts.

Checked all connections.

Any ideas? I'm running out of power...

Thanks.

[Vic]

Hi o-g-g,

Just to try to get things going ...    IIRC,  RFR #1  is the initial wake-up state.

So,   you checked ALL connections?  With 4 strings of PVs,  you probably have a Combiner.   Did you check all of the connections there?

Did you check all of the connections at the Classic's blue cable connection terminals?

Did you check the connections on the output side of the Classic  --  from the blue terminal block,   at the output breaker,   and all of the rest of the way to the battery?

EDIT:   Have never run the Classic FW Version that you are using, but,  it probably would not hurt to Update the FW to the current version for Classics  --  2126  --   if that is something that you could do fairly easily <

You could try saving all of the custom settings you have in the Classic with the Local App,   do the VMM,   reload your custom settings,   and see what happens.

Going to the Tweaks menu,   and Force Bulk should behave much the same as when you got the Classic to awaken and charge,   before,   but might be interesting to try.

Also,   it could be useful to try to see how the Classic goes into Resting,   although this may be difficult to see.   You might be able to sleuth something via the Local App's data ...

Just some random thoughts,   Vic

[off-grid-geeks]

Thanks for the reply.
Yep, checked all the connections. My next step was going to be what you suggested, save all the settings, factory restore, reload.
But about 45 minutes after I posted, it was back to charging in bulk.

I'll keep an eye on it, see if it repeats.

I'll try the force bulk too.

-Alan

[off-grid-geeks]

It did it again today.

We've had 5 days of overcast.
Started this morning at 72% SOC, and clear skys.
A good Bulk charge got underway.
By 10:52, still clear skys and lots of sun, SOC was at 81% and 48.3 amps going into the battery bank, which was the peak as of that instant in time.
Then instantly went into 'resting'.
PV voltage was showing 65.7 volts, so the classic could see the panels, but PV current was zero.
Stayed that way the rest of the day, SOC slowly declining as house usage pulled from the battery bank.

Very frustrating to finally have a nice sunny day to replenish the batteries after 5 dismal dark days, and the classic goes wrong, wasting all that sunlight. I wasn't home or I'd have kicked it real hard.

[Matrix]

Random thoughts.   

Rebulk Setting?

Skip days setting (aka days between bulk)?  Absorb volt setting or time?  End amp setting way off?

Have you tried a complete factory rest of the classic?   

[off-grid-geeks]

Matrix,
Just as a cover comment, the system has been running without any problems for 4+years, no changes have been made.
So Settings should not matter in this new development.

But here are your answers, thanks for your input.

Rebulk set for under 25 volts
Skip days is zero
Absorb has end amps disabled, time set for 4 hours
I have not done a complete factory reset.

Also, just to emphasize, the drop to resting started at the highest input, 1.2kw from the panels, and still in bulk.
So the absorb settings should be immaterial, also rebulk.

[Vic]

Hi o g g,

Assume that you were in Solar Mode.   You might try changing to Legacy P & O Mode,  just to see what happens.

When the CC was resting,   what was the PV input voltage to the Classic,   and the battery voltage?   EDIT:  OH,  you noted that<

It would not hurt to Update the FW  to the latest ...

Am cooking dinner now,   will ruminate.

As noted earlier in this Thread,   it would be nice to have either watched what had transpired just before the Classic went to Rest.

Do you have any data from the Classic that you could share?

Please DO try Legacy Mode,   realizing that this process repeats fairly infrequently.   At times hazy conditions can upset the MPPT tracking in Solar Mode ...   it is rare,   though.

Thanks,      Vic

[off-grid-geeks]

Thanks Vic,

I was likewise thinking of trying Legacy.
I'm mostly just stumped why this started the first week of March, and has happened now 3 times, after 4+ years of no issues and nothing (settings) have changed.

[Vic]

Hi o g g,

Here is some info on RFR:

http://midniteftp.com/forum/index.php?topic=2034.0

Just had a chance to re-read this Thread.

SO  you know about RFR - good.

Later,   Vic

[ClassicCrazy]

using follow me by any chance ?

Larry

[Resthome]

Vic is correct as usual, we need the RFR #. And your firmware versions. If you are getting a RFR 104 and you have old firmware you need to update to the latest firmware. And make sure the MNGP is not in the Daily logs or the Classic will reboot. No other charging source to you battery bank? Is the Classic in Bulk or Absorb when it goes to Resting? Also if the battery voltage is higher than the Absorb set point the Classic will go to resting.

[dgd]

Ogg,
When you noticed the Classic change to resting you left it that way the rest of theday?
You also say its been running 4+ years.
I’d suggest a complete power shutdown for the Classic, keep it off for at least 15 minutes to let everything in the circuit boards discharge. Shut off the battery breaker for the Classic and the pv input breaker too.
Recheck all the cables into the Classic as copper cables have a tendancy to creep loose over time also checking the cabling to the breakers.
If the problem persists then it may be time to get thespare Classic unpacked and installed so you can arrange to get the original one serviced by midnite 😀
Dgd

[SolarMusher]

Ogg,
Take a look at the batt temp and check your temp limit, it may be too low or your batteries are a bit hot.
I saw that problem two times but don't know if the MNGP was resting or if it was showing a temp limit message.
Agree with others, update to the last firmware.
Good luck,
Erik

[boB]

When this kind of thing happens, the most important things to ask are the battery voltage (24V) and two different PV
input voltages...   Open circuit PV voltage (Voc) and I am assuming in your case it is 67 volts.

The Voc input voltage is just that, open circuit or OFF.   The big question is...  Does the PV voltage drop
down at all when the Classic goes to Bulk MPPT ?  It should ALWAYS drop down from Voc when trying to
charge.... In fact, it should drop to around 80% or so of Voc if no shading on the panels.

If it is not dropping input voltage down, the either the Classic is broken and needs to come back, OR
it is possible that the top control PCB circuit board has come partially unplugged from the power
board underneath.  It doesn't hurt to turn off the power to the Classic (input and output) and try pressing down
on all 4 corners and the middle of that PCB and then turn it back on again and see if the PV input voltage
drops down some from Voc.

If the input voltage does drop down from open circuit, then it could be a bad (high resistance) PV connection.

If that doesn't help, then I would call for an RMA. 

You can temporarily connect the PV positive to battery positive while watching the battery voltage closely to
make sure it does not go up 28 or 29V for but only a few seconds.

If the batteries are thirsty for energy, that should put a bit of SOC back into the batteries to help out.
But this won't put out a lot of power since the maximum power point voltage of the PV is in the 50 volt
range most likely.  If you do this, just be careful the battery voltage doesn't rise too high for very long.

But geesh!....  4 years it's been working !  Looks like our planned obsolescence  circuitry is early
by one year.   

Just kidding

boB

[Matrix]

You can temporarily connect the PV positive to battery positive while watching the battery voltage closely to
make sure it does not go up 28 or 29V for but only a few seconds.

boB ... slightly off topic,  but aren't voltages higher than that during normal  charging?   EQ is 32.4v on some 24v banks.  What happens to batteries if those voltages were held long periods of time.  Hours?