I have an MPPT 100/30 with a Bluetooth dongle. It has worked perfectly for 18 months. Recently I disconnected and reconnected the solar panels but now the controller sits in the off position.
I have tested the connections and get 57v at the wires to the PV. But when I connect the wires if I put a multimeter across the PV terminals there is no reading.
The blue LED blinks every 4 seconds or so.