150 randomly refuses to charge

[lambertmt]

I have a classic 150 on firmware 2193, and it randomly refuses to charge some mornings. Some days, it will give me "GOT COMM?" error, some days it only says bulk MPPT, but power is zero.

If I catch it in this state, which is about 50% of mornings, I cycle the power off and on, then it starts charging normally.

Any ideas?

[ClassicCrazy]

What is your battery voltage and what is your pv input ?
Larry

[lambertmt]

Thanks for asking. It is a 48 volt nominal bank, and I have 3500 Watts of PV input. String voltage is about 90 volts. This is my fifth classic on this battery bank. I have attached a picture of the follow me settings. Of note, this is my East facing array for this bank, so it wakes up first before the master, and it gets shaded before the rest of them. 

[ClassicCrazy]

The Got Comm would be an issue with MNGP communicating with the Classic I believe.
I had an issue once where my pv voltage was too low and didn't start charging too quickly in the morning so that is why I asked about your PV . Maybe check your connections on that string?
If it is Follow Me do you see the blue led flashing ?
There is a test -
https://www.midniteftp.com/support/kb/faq.php?id=91
also take a look at this one
https://www.midniteftp.com/support/kb/faq.php?id=112

If it was me I would probably back up the settings with Local Status App and then do a VMM firmware reset, and restore the settings to see if that fixed any glitches.
The Midnite techs might have some other ideas but that is all I can think of.
Larry

[Hockey]

I have a classic 150 on firmware 2193, and it randomly refuses to charge some mornings. Some days, it will give me "GOT COMM?" error, some days it only says bulk MPPT, but power is zero.

If I catch it in this state, which is about 50% of mornings, I cycle the power off and on, then it starts charging normally.

Any ideas?

I had something like this happen recently.  Same symptoms, except I don't recall the "GOT COMM" message.  Turns out the control board had become partially disconnected from the power board underneath.  It probably happened when I took off the cover and inadvertently yanked on the blue communication cable.

Check this video starting at around 4:10.

In my case, I snapped the control board back onto the white plastic standoff posts, and everything started working again.

[lambertmt]

Thanks, gentleman. I will give this a shot.