load > pv during day
I have a system with fifteen 270 W panels (4 kW), an Outback FM80 charge controller, GS8048 Inverter, a Mate3S control panel, and two strings of four NC200 batteries. The system works great for my household needs, but I want to pump water from my well for the household and light irrigation, which would take about an hour or two in the middle of the day. The pump is about 16-17 amps and can run at 14 amps with less flow, but with inefficiency and so forth about 0.5 to 1 kWH over the course of the pumping will have to come from the batteries. The batteries could easily recharge on Flotation before the end of the day. I am just not sure if the batteries are designed to handle that, or whether it will weaken them or shorten their life. I am trying to get a third string of batteries, would that make my system stronger for pumping at a deficit in the middle of the day? Or is it necessary to buy more panels (and another charge controller, since the FM80 is maxed out with 15 panels) in order to pump without messing up my batteries?