I have built a portable solar system and recently constructed a portable gold mining wash plant that uses a 5000gph 120VAC submersible water pump. As I'm a long way away from any gold mining country I've only had the wash plant in action one time for 4 days, several hours per day. It works great but it was cloudy most of the time so could not get an idea how efficient everything was running. Ended up powering off the vehicle alternator much of the time. Such a lousy feeling to be testing a system 300 miles from home and having cloudy rainy days 3 out of 4. Testing with a Kill-A-Watt meter the pump draws 270 watts off the grid power. 330-360 watts with modified sine wave inverter. I'm hoping to improve the efficiency with a pure sine inverter. Today I ran a simple test with the mod sine inverter using a small 120 VAC heater as a load, a 12V 50A shunt and multimeter to measure 12VDC consumption and found 242 watts into the inverter for 205 watts out. Does anyone know if the Kill-A-Watt meter is accurate measuring a modified sine wave? Would a pump motor run more efficient on pure sine wave AC power? What would be a good estimate on the 12VDC wattage required for a pure sine inverter to get 270 watts of 120VAC. The thought of precious solar electricity being consumed to heat creek water makes me a bit ill. I'd like to try to get the most power out of my 280 watts of panels as possible and wonder if the expensive shorter lived MPPT controllers are worth it. I'm using a single 12V 100ah deep cycle battery. May have room to pack another 100 watt panel with the gear but need a Tetris game expert to come pack my truck for me.
I'm also questioning how would a 100ah deep cycle battery handle 300+ watts of charge? Is this too rough? Thanks for any input.