Bloody hell, you can have 240 V mains hooked up to the pump, but they're worried about a few volts out of a solar cell
You can have 480, 575, 600 hooked up. It has to do with the sealing of the electrical devices, conduits and cords to deal with the Explosion Proof regulations.
I am not sure of DSEAR regulations but it would require the solar panel and charger to meet Class 1, Group D, Div2 regulations in the US. Then it would have to involve the battery containment as well. Cost wise you would be looking at an exorbitant cost.
Moving out of the 4m radius as Stu B indicated allows use of normal equipment.
VFD