They can, but you need a suitable equipment- thicker wires, at a minimum. Wiring in parallel means the voltage is the same regardless of the number of panels, b

They can, but you need a suitable equipment- thicker wires, at a minimum. Wiring in parallel means the voltage is the same regardless of the number of panels, but the current sums up- so your inverter and/ or controller will need to be rated appropriately.