PV voltage won't stay up

[j0hn]

I am building a new system from scratch using 4x100W panels in series feeding a Growatt SPF 3000TL LVM-24P, connected to 2x12vx100Ah batteries in series and adding 2 more to do 2S2P. The panel voltages are individually ~19v and stable, connecting them in 2, 3, and 4 in series raises the voltage as expected and it is stable at the panels. When I connect the panels to the Growatt it will show voltage climbing up to a max of about 55v then suddenly dropping down to 26.5ish which is my batteries current voltage. then is slowly climbs and then drops again. The biggest problem with this is that the charge controller needs 30v, so it keeps going on and off with these cycles. Is there anything else I can check on the panels? I talked to Signature Solar who I bought the Growatt from and they said it looks like a bad panel, but I feel pretty confident in the panels.

Has anyone else seen PV voltage climb and drop every couple of minutes like this?

Thanks for the help!

 

[MisterSandals]

Cross posting bad. You should delete one of the 2 threads.

 

[Pete@SolarBatteryBarn]

I have seen this many times with bad solar panels.
This is why you should test used panels on an MPPT charger because this is a common problem.
It can take some time to show up so be sure to test for about 10 minutes.