I'am in the starting phase of putting together a backup solar system. I have a 4000 watt pure sine wave inverter 12vdc input 120 vac out put. 6 100ah deepcycle gell batteries and 4 200 watt solar paels rated 12vdc , I have not put it together , Im looking for a good controler and not sure what amp I should use i was thing 100 amp controler. Any one have any advice.