No PV recognized on my MPPT LV6548 all in one system?

I have a brand new MPPT LV6548, having had good experience with the 24volt version.

I just set up the system today with 4 SOK 100ah batteries in series. Batteries are fine and the MMPT sees them fine.
I dont have any utility power source, but the AC out is blowing a floor fan using battery power
I have 240watt panels from Santan solar and they are putting out abut 100-120Volts of power at the terminus of the lines. I've been playing around with using 3 or 4 panels in series, and the voltage is within specs, but no matter what I try, the MPPT will not show any panels connected.
I put it in SUB mode so solar should be first priority.
There are no faults or errors.
My LCD shows Battery>DC/AC>Load but there are no icons for PV or DC/DC
Ive tries both sets of PV inputs PV 1, PV2.
Any ideas what could be wrong?

Update: I even attached a solar panel directly to the PV inputs, and it doesnt read any voltage, so I know its not my MC4 connectors / PV lines I crimped myself. Even if a single panel doesnt meet the minimum voltage, it should still recognize the low voltage is there.

Thanks in advance

The PV input polarity is correct?
Does it show any Voltage at the PV Input terminals?

Polarity is my first thought as well.
Check that PV output is positive to positive, and negative to negative.
I hope you have a digital volt meter.

Yeah polarity is good, my volt meter confirms it, and when i hook up my panel directly to the PV inputs, you cant really get it wrong - male to female, female to male.

BigIslandRyan said:

Yeah polarity is good, my volt meter confirms it, and when i hook up my panel directly to the PV inputs, you cant really get it wrong - male to female, female to male.

Click to expand...

Oh, you would be surprised how easy it is to get it wrong. Polarity to mc4 connectors is not universal…

Bud Martin said:

The PV input polarity is correct?
Does it show any Voltage at the PV Input terminals?

Click to expand...

it shows voltage at the MC4 connections that touch the PV inputs. I guess i could open it up and see if there is any voltage at any point downline inside the unit? Doing this out in the Arizona desert in the heat with biting flies.. not fun.

You have to measure right at the SCC PV Input terminals and also verify that it shows correct polarity.
The SCC has MC4 receptacles, correct? so you have to trace the wires from the MC4 receptacles to the terminals some where inside the unit to check the incoming PV input.
So for sure you have the correct Voltage polarity from the panels, right?
Since your unit has two sets of PV inputs (PV1, PV2) because it has two MPPT's inside so I doubt that both MPPT's are bad.

LV6548 requires a minimum 90v to start charging, can you confirm its more than that?

When testing the polarity… are you sure the leads on the meter are correct? I’ve seen it all on here.
By far the most common cause of PV recognition errors is polarity.

Vmp will be in 85% range of Voc but inverter should at least show Voc initially.

Well, that was the most frustrating troubleshooting ive ever done in my life. I was verifying voltage at the tips of the MC4 connectors, but as soon as i plugged them into the ports on the unit, the voltage would vanish just 2 inches away. So i put my charger leads right on the PV board inputs, and then tested the next spot down the line. Voltage passed through OK.
It turns out that the MC4 connectors that are provided with the MPP unit are extremely finicky, or my MC4 crimping skills are lacking. Or both.

After redoing multiple MC4 connectors and wiggling the shit out of them after snapping them into the input MC4's - i got a beep and the PV was seen.
But slight wiggles of the PV lines would make it drop again. They are very finicky. I dont trust the MPP connecting ports at all.

I wish there was a way to apply bare PV wire into a terminal.

But at least it shows me the PV icons and is charging my batteries. Now on to re-running the wiring and cleaning it up.

Thanks everyone for your guidance.