With 42 panels, what do your strings look like? Are the voltages of your strings in the specified range for a Flexboss 18? The max for any given string is 600v, but usable is less than that and you really want it under 500 volts. With only two mppts on a Flexboss18, 24 panels per string seems like a lot. What are the specs for your panels? I have a Flexboss 21 with 400 watt panels and the max number of panels I can have per string is 14 before my the voltage is over what is recommended for each mppt.
