I bought an AC200Max (hereafter Max) a few years ago. I never used it, due to family medical issues. I kept it properly charging up and down every few months. I moved into a house and hooked up 400 Watts of solar panels, and it worked fine for a couple of months charging a fridge and a couple of lights. About 6 months ago, I bought an AC500 and bought a pallet of solar panels; therefore, set the Max aside for a few months while setting up the AC500. After three months of non-use and proper monitoring, I set up a few solar panels on the roof and connected them to the Max. It does not take PV input. I have used my Clamp Meter and am getting 137 volts in (max allowed is 145) from 4 panels. This 137 voltage is measured right up to the blue plug that goes into the Max. I have calibrated up and down, 0% to 100%, 3 times. It simply will not acknowledge any PV Input on the screen. Anyone have any ideas, besides taking it apart to look for fuses, etc.? Everything else works fine, and I can charge the Max from the Bluetti adaptor.