It depends on whether your off grid solar system is running at a full load for a long time or using it occasionally, just like: induction cooker or kettle, etc. Because if we only use several minutes or less than half an hour, we don't need to match with solar panel with same power. Solar panel with 900W can generate electricity 4.5kWh in 5 hours, the electricity consumption of 2kW pure sine wave inverter in an hour is 2kWh, if just use occasionally, it will be enough. Of course, you may say I have many LED lights used in the off-grid solar power system of the farm, that you may need configurative 6*300W Mono/polycrystalline solar panel. Meanwhile, you need to replace the Mppt solar charge controller that is twice as large. Here we highly recommend Mppt solar charge controller. Although PWM is cheap, its efficiency is 20%-30% less than that of Mppt, which will lead a waste of your solar panel.