hello, the mppt 250/60 does not receive nothing from the panels. i disconect the pv and battery a coulples of times and nothing happen. is like the entrance o the PV die, y use the tester i put in the screws of the PV and show me 0,0 V , but when i put the tester on the PV cables showme the voltage of the 8 panels 131 V. plese help.