E26,
Do you know the wattage of your pump? Or amperage?
I would doubt that one battery would be able to hold enough charge to last the night. Further, you would need to have enough panels to run the pump and recharge the battery every day. That would be a tall order for those panels. Once we know the runtime you can reasonably expect, I believe other experts would have you consider starting your pump some amount of time before sunrise so to get the cooling benefit and allow the batteries to start getting refilled with the sunrise.
