Midnite classic 150 only showing Voltage from panels when combined switched off

[NotApollo]

OK, this is probably a stupid question to most of you, but this is new to me. I had an electrician come out and set up my new off-grid solar system. I ordered a kit from Renogy, and have 1200 W of solar panels coming in to the midnight classic 150.  I Couldn’t get the charge controller to show any power coming from the panels. It would show 0.1v and resting, even when sunny.  I accidentally noticed today that when I shut my panels off at the combiner box, I’m all of the sudden showing voltage coming into the midnite classic 150.😟.  Is something wired wrong at the combiner box?!
Thanks

[ClassicCrazy]

Can't answer  your question about without knowing how your panels were wired to the system - how many pv - how many in series , how many parallel .
Maybe you can take some photos of how they are wired into your system . ( open up the boxes if possible )
Did your electrician test the system when they were done ? That is the person you might want to confer with.
How much voltage did you see when you shut off the PV ?
It is normal for the Classic to show a small amount of voltage at night or when there is no PV . It is voltage from battery that Classic needs to stay on.

Larry

[boB]

Did the electrician test the system after he installed it ?

Did it work at one time before this ?

If not, check the polarity of the PV solar coming into the Classic.

When nothing is connected to the PV input of the Classic, the Classic's display will show some voltage less than the batter voltage.  Maybe around 2/3 of the battery or 1/2 or so.

After that, if either the PV is reversed, plus going to minus and minus going to plus, it will show zero or 0.1 volt or so. 

If the PV input of the Classic is shorted internally (bad classic) then you would not see much, if any input voltage either if it was turned on or off at the PV input.

The voltage you see on the Classic input when PV is turned off comes from the battery and through a resistor inside the classic.

Check the polarity of the input.  Also, telling us what voltage you see when PV is turned OFF might tell us something, along with the battery voltage you are using.

[NotApollo]

When I flip the breaker at the combiner box to on, my charge controller shows 0.1 V and is resting.
When I flip the breaker at the combiner box to off, I see a varying amount of voltage based on sunlight. 8 to 5 V. It’s been fairly overcast. I don’t think , My buddy the electrician checked the system, as it was pitch dark when he left, and he was already late.
It’s two pairs 320 watt Renogy panels wired in series to combiner box.

[NotApollo]

I have eight 12 V batteries wired in parallel for a bank.

[ClassicCrazy]

When I flip the breaker at the combiner box to on, my charge controller shows 0.1 V and is resting.
When I flip the breaker at the combiner box to off, I see a varying amount of voltage based on sunlight. 8 to 5 V. It’s been fairly overcast. I don’t think , My buddy the electrician checked the system, as it was pitch dark when he left, and he was already late.
It’s two pairs 320 watt Renogy panels wired in series to combiner box.

If you have a volt meter turn the breakers off in the combiner box and check to see if each string is negative on the buss bar and positive on the breaker.
Then turn the breakers back on and  go inside and look at where ever the wires go to the PV input breaker  and check voltage for correct polarity there .

If you can't go poking around with a meter - at least look inside the box where the wire from the combiner box goes to . I see the electrician put white tape on it . See if there is  white tape on the one that goes to the breaker before the Classic ( although it is possible to mix up tape on a cable ) . You really need the installing electrician to come back and check it all out.

Larry

[NotApollo]

Thanks

[ClassicCrazy]

I have eight 12 V batteries wired in parallel for a bank.

You can  have some issues keeping that many batteries in parallel balanced and may have premature failure on some of them because of that.
At the least check your wiring to best practice with a lot of care for the wires being equal length. See link
http://www.smartgauge.co.uk/batt_con.html

Better would be to wire it for 24v ( depends a bit on your PV ) . I guess that decision depends on what you are using for an inverter .
Just some thoughts on design considerations.

Larry

[boB]

OK, 5 to 8 V on the input when PV disconnected and 12V battery.

I would say that either the PV is wired backwards  (plus and minus are reversed) or it is shorted plus to minus.

A big question is...   HAD this system worked before ?

If not, then I would call your electrician and have him/her come back and fix it.

Maybe that electrician has never worked on PV systems before ?  If not, they may not be as knowledgeable working with DC.

Parallel 12V batteries can work OK as long as they all are wired so that charging and discharging is distributed evenly.  That depends on the wiring.

You don't want to have the batteries unbalance, charge wise.   But that isn't part of this problem.  Batteries can come next.

[NotApollo]

He’d not worked DC before...
System NEVER worked.
Just hooked up last Saturday night.
It’s been so overcast in Wisconsin.
I’m Hopefully talking to a solar technician tomorrow.

[mike90045]

I have eight 12 V batteries wired in parallel for a bank. 

That's a classic newcomer mistake.  instead of 8 parallel batteries, which are nearly impossible to keep in balance, you should have sized for a 48v system, with 4 series batteries paralleled with another 4 series batteries.
You already have the link for the wiring suggestions.

PV panels - do you have 2 panels, or 4 panels ("2 pairs") ?

[NotApollo]

Well, I could change it, right?
Midnite classic and Renogy 2000w inverter charger both let me enter battery voltage of bank...

[NotApollo]

Never mind...12 volt inverter

[boB]

First, get the solar charging to work.  It is most likely as simple as reversing the positive and negative PV input wires.

Then you can think about upgrading something.