Classic 150 not fully charging batteries and decreasing voltage daily

[mohaveoffgrid]

On two different installs I'm having the same problem...The charge controller is not getting up to voltage to adequately bulk charge or equalize. One of the arrays is small (1500W) but the other is over 3000W. I have followed the recommendations of the string sizing tool and it's just not getting there. What can I do?

[Mtn Don]

Some incoming and outgoing voltage numbers would likely make this easier to figure out.  Plus the CC settings.   

These are newly installed; never produced what would be expected?


Connected to battery first, battery voltage set and then the PV array input connected?

[TomW]

First, I would shut off all the breakers so the Classic is powered down.

Then power up the battery side of things, followed by the solar array in.

Go through the setup from scratch make sure the Classic has the correct battery voltage.

If that doesn't help then you need to check all voltages at the Classic's blue terminal block and be sure they are correct. These things are often wiring errors, loose connections, etc.

Write down your readings and return with more specifics on the system and we can probably help sort it out.

Best of luck with it.

Tom

[Westbranch]

To add to Dons comment, a full description of the main components of the system is needed to assist in evaluating what really is wrong...

[TomW]

When all else fails, do a VMM Vulcan Mind Meld

That is when you power down the Classic and hold the left and right arrow keys down and power it up. This resets to factory default settings and may clear any errors in the set up. Then you can go through and do a fresh setup from scratch.

I should have put that in my first post as it is often a good thing to do if things are not "normal" after the initial commissioning of a unit.

Tom

[Vic]

Hi Mohave..,

And,  while you are at it,  please confirm that you have the latest Production FirmWare installed in the Classic and MNGP (Graphic display)   Here is the Link if you need it:

http://www.midnitesolar.com/firmware.php?firmwareProduct_ID=1

Good Luck,  Vic

[boB]

What is the battery voltage Absorb setting ?  Is it going into Absorb or, staying in MPPT which
would be below the charge voltage setting ?

If it is NOT getting the battery voltage to absorb, check the PV input voltage against the
PV's Voc open circuit voltage value.  That should optimally be around 75% to 81% or so
of the Voc of the PV array, not matter what size it is.  This would be without partial shading.

The next thing to check would be to make sure there isn't some battery temperature issue.
You can view the Absorb, Float and EQ temperature compensated voltage set point
by going to the CHARGE---T-Comp---VIEW  Menu to view the present battery "target"
voltage.  If it appears too low, please go to the STATUS menu, press STATUS 3 times until
you get to the Whizbang Junior menu.  Press SETUP---MORE and make sure the REFERENCE
temperature is correct...  Usually this is 25.0  degrees C.   The VMM in the MNGP does
not correctly setting this to 25.0 as default, although the jumper operated factory restore
(mainly for Classic Lites) does set it in the current firmware.

You may have already called us at Midnite and fixed this but hopefully you can return here
to tell us what you found, if so.

Thanks !
boB