OldNewby

i bought a ProVista MPPT 30A controller for R1500 incl in December. works fine for me. I have 4 x 180w panels on it and am getting around 27.4amps out of it.

Hi David,
 
don't know the company either...
 
I usually approximate the needed amps from the power usage specified by the appliance... e.g. if it is 300W at 220V (meaning then 1.4A) it would then be 25A at 12V to get to 300W. (I hope that is the right approach!?)
 
Considering you want to drain your batteries only to 50% capacity, you have 220Ah available meaning a 300W appliance could run for 220/25 = 8.8h. If your charge controller could do 10A for 5h (very genereous), it means that you replenish only 50Ah in one day, so your set of batteries will never be fully loaded at a constant usage of 300W.
 
If one sticks to loading the batteries with 50Ah per day, an appliance switched on 24/7 should not use more than 25W constantly. Your limiting factor for your setup is the amount of solar panels...
 
Hope that makes sense.
 
Wolfgang