classic showing low input and not charging

[ClassicCrazy]

My classic is doing some strange things today. I hear the relay click and then see it saying it is resting due to low light. The input voltage shows 70 some volts. The it went back into bulk MPPT mode and it is only showing input volts 13  with the battery voltage at 13.3 but says it is charging 47 watts .
This is what the alerts screen says
WARNINGS
- Partial Shading Detected
INFORMATIONAL
- Input Voltage Lower than Output Voltage

The sun is out - no clouds
I powered off the controller once and it operated normally again but then started doing this same thing again.

Any ideas ?

[ClassicCrazy]

It went back into low light resting and then came back on - now it is back to operating normally again 69 volts in 287 watts charging battery 14.5 volts -- weird

[boB]

It went back into low light resting and then came back on - now it is back to operating normally again 69 volts in 287 watts charging battery 14.5 volts -- weird

Yes, sometimes will find that low voltage when it first comes out of resting. Subsequent sweeps should find the higher voltage though.  It will fix that first sweep problem soon in a update.

[ClassicCrazy]

This morning I noticed the classic showing lower voltage on the display than I read at the batteries. I also notice that it says resting and 5.2 volts in so I disconnected the PV and it still shows 5.2 volts in.

I reloaded the firmware making sure I waited for all the black screens to go away on their own and restarted the classic. Still shows 5.2 volts in but the battery voltage is showing about 0.2 volts lower than the meter reads them . Connected the PV back up and it read the PV voltage 70 some volts and went to Bulk MPPT but then reverted back to 12.4 volts input and going back and forth between showing Bulk MPPT and PV Shading . It is very early morning without full sun .

It just corrected itself and is charging about 60 volts in , went to resting after awhile showing 80 volts in , came back to charging at 60 volts in.


I understand that you know about this low voltage / shading issue and will correct it in an update. 
My main question at this point is should it be reading 5.2 volts in when there is no PV on it ? 

[Halfcrazy]

Yes the voltage at rest with no PV is normal. It sure sounds like a high resistance connection somewhere?

Ryan

[boB]

Right.  You will see PV input voltage close to around 1/2 of the battery voltage with the PV input disconnected.

This does sound like an intermittent connection somewhere on the PV array input side of the Classic.

In the daylight, you should always see higher than battery voltage on the input of the Classic when things are
operating normally.  When the Classic is actually running (Bulk MPPT, Absorb, Float, etc.) and producing "some"
amount of power or keeping the b attery voltage at the set point voltage, that input will be higher than battery.

I have definitely seen what you were seeing (PV voltage very close to battery voltage) but normally
will only be just below battery voltage with bad connection on the PV side.

When your system does work, how much power or output current do you see ?  If it is lower than
expected, it really sounds like a bad or intermittent connection and you will want to wiggle wires
and re-tighten and maybe use a volt meter to see where the PV voltage is making its disconnect.

Another sanity check can be tried by pressing and holding the soft-right key down (from main status
menu) when you find the PV input at a low voltage and the Classic running.  This should bring the
input voltage up and you can watch to see if the output power rises when that voltage goes up.
If the output power does not go up much or at all, you definitely have a bad connection on
the PV input side.

It's all worth a try I would say.

boB

[ClassicCrazy]

What  the normal sequence of operation for the Classic in the morning and evening when the sun is first coming up or going down and the light conditions are low ?

Mine still does the same hunting type behavior where it keeps going to resting then to bulk at full input voltage but then input will drop to near battery voltage. All this straightens out when the sun is more fully on the panels .  I have double checked all my connections and wiring and everything seems to be tight and correct.

But early morning and evening there is a lot of relay clicking going on as the Classic tries to figure out what status it wants to be as it goes from bulk to resting back to bulk charge. 

[boB]

ClassicCrazy...

If you want to, please give this new semi-beta software a try and see if it helps your
low light operation some or a lot...

http://fusion.midnitesolar.com/MidNiteSolarSetup_10-2-2012_v3.01.exe

You will (probably) need to do a Vulcan Mind Meld (VMM) initialization from the MNGP Remote.

I think you will find that this handles the low light and sticking near battery voltage much better.

Let us know if you have any problems upgrading or questions about the software in general...
Also let me know if it helps or not.

The Absorb time will be somewhat different.  By default, there will be no minimum (or maximum)
absorb time but just  "time".

boB

[ClassicCrazy]

Okay Bob - I used your link to do the updates and also did the VMM .  I will report back to see what happens now around sunset and sunrise. 
here is what the status panel shows me for revision after these updates
- Classic Rev: 1070
- Network Rev: 1024

Thanks
Larry

[ClassicCrazy]

A few things I have noticed
Local Status Panel won't change settings - maybe some but not others
Parameters available in Local Status panel not showing on menu on Classic for example Absorb Max time and Min time in Local Status Panel but on Classic menu it only shows Absorb Max time setting
Classic display was showing float and message showing OCP IS OFF !  ( no warning showing in Local Status Panel) powered Classic off and back on now in Absorb but OCP IS OFF ! still displaying

[boB]

Okay Bob - I used your link to do the updates and also did the VMM .  I will report back to see what happens now around sunset and sunrise. 
here is what the status panel shows me for revision after these updates
- Classic Rev: 1070
- Network Rev: 1024

Thanks
Larry



Yep.  I think those are the latest revs numbers.   The date shown should be from the other day
or last week.

[boB]

A few things I have noticed
Local Status Panel won't change settings - maybe some but not others
Parameters available in Local Status panel not showing on menu on Classic for example Absorb Max time and Min time in Local Status Panel but on Classic menu it only shows Absorb Max time setting
Classic display was showing float and message showing OCP IS OFF !  ( no warning showing in Local Status Panel) powered Classic off and back on now in Absorb but OCP IS OFF ! still displaying

The OCP IS OFF !  message is not a big deal but should really not be showing if you did the VMM which you did.   That is kind of weird.
I will look into that one.  That message is just kind of annoying to show up is all for now.

OK, editing what I JUST wrote because I didn't digest your posting close enough...

Yes, there will not be a minimum absorb time in the MNGP but will be in the Local App until it gets updated to coordinate
with this latest Classic revision.

You will notice that the soft-left key in the Absorb time screen on the Classic says  (VMX) which means "VariMax".
I will explain this better soon but for now, realize that what WAS Absorb time MAXIMUM is the Absorb time unless
you enable VMX.  I would just leave it the same for now.

From the Local App, just use the Absorb MAXIMUM time adjustment for your Absorb time.

boB

[ClassicCrazy]

Just to make sure I just did VMM again and the OCP IS OFF message is gone now.  When I did it the first time I didn't get the time set right in the first screen and went to a menu and redid it. This time I did all the Solar ON , voltage settings, and date right after the VMM button push, then it resent the data .  Maybe I didn't do it right the first time.

[boB]

Just to make sure I just did VMM again and the OCP IS OFF message is gone now.  When I did it the first time I didn't get the time set right in the first screen and went to a menu and redid it. This time I did all the Solar ON , voltage settings, and date right after the VMM button push, then it resent the data .  Maybe I didn't do it right the first time.

WheW !  Great !  You're now good to test that low light production.

Glad it's up and running at least.

boB

[ClassicCrazy]

Sun is setting and the Classic has started to cycle between Float MPPT and Resting - about every minute or two float then resting low light  for about 15 seconds or so . The input voltage is staying up above battery voltage  and gradually dropping each float/rest cycle  as the sun goes down - 60 to 77 volts resting then dropping to 40 to 60 volts when it goes back to float. It has cycled this way probably 20 to 30 times since the sun started getting low and no more charging happening.
I haven't seen it do any of the previous behavior where the input voltage would suddenly drop below the battery voltage.

How does the Classic  finally decide it is night time ?

With the sun setting on the horizon now it seems to have decided to stay in Resting Low light with input voltage at 50 volts and battery voltage beginning to drop a bit - I don't have any loads on the battery right now so that is why it has been floating around 13 volts since sun began to drop.
In the morning I will watch it again if I don't sleep too late !
   

Edit - now with not much light on the horizon it is going back to float at 13 volts input , battery 12.8 volts  Resting input 12 volts    ..... not coming out of resting this time with input voltage dropping to 6 volts . I guess the Classic finally went to sleep for good now ! 
How many relay clicks - resting/ charge cycles are normal for the Classic to go to sleep around sunset time ? I guess I would estimate 25 to 35 on this clear cool fall evening in Wisconsin .