To figure out what controller you would need, we need to know how the panels are wired, what the Voc (Open Circuit Voltage) is and what the coldest it will get in your area is. (The Voc goes up as the temp goes down)
Look up the all time low for where the panels will be and let us know.
I looked up the REC40NP and the Voc is 40.8V and the Voc temp coefficient is -0.27 %/°C
Your panels are almost certainly wired in one of three ways:
Given the application, I assume it is wired like 'A' (All 4 in series). This will give the highest voltage for the run down to the pump.
Assuming that is true:
- The Voc for this config is 163.2V.
- I did the math for a coldest temp of -20C (-4F) and the Voc goes up to ~183V or higher.
If my assumptions are true, you need a controller that can handle up to 183V on the input.
However, before we can go much further there are some basic questions to answer:
Will this system be totally off grid or grid tied?
Will you want to grow the system in the future?
- More Panels?
- More Storage?
- etc