There is a company local to me that is selling a large number of JA Solar 315w panels for $50 each. I'd like to build out a system to offset my grid usage. Currently I have a 900w setup, using the same panels, at my farm stand that I use a victron 150/45 to charge two 12v batteries then run a cheap inverter to power a fridge and security cameras.
What are some resources I can read to build out my system correctly. Our utility, NIPSCO, does net metering using a credit system with no actual payback. My monthly usage is in the 2k kwh per month with most of the energy usage from grow lights during the winter and an irrigation pump/refrigeration in the summertime.
Jump on that panel deal!!! Immediately pick up as many as you can carry.
First, let me be clear about the numbers? When you say you are using "2k kwh per month", you mean you are consuming 2000 kWh each month? That works out to be ~66-67kWh per day? That is really a lot. No way that can anything 12V handle something like that.
If those numbers are correct, then going with a large 48V whole-house sized system is appropriate. I'd look at a 48V sine-wave inverter in the 4000-8000W range. I like Outback and Schneider, though they are not the only "best choices". Take a look at Schneider's Conext 4048 and the 6848Pro. Also look at the Outback Radian models 4048 and the 8048. The larger units from both companies can be paralleled for greater capacity.
Assuming you get ~3 sunhours in winter, and maybe 6 in summer, to make that much power in December you are likely to need ~20,000W worth of panels. That's huge! Right now my own 48V system has 5500W of panels online as of today, and I can reliably make ~15kWh in December, so I'd say that number is close to spot on?
Do you really want to build something that big? It will need massive battery, and it might be more cost-effective to scale the system back and invest more in North-facing insulation and such. I'd say the first thing is to carefully go through your useage data, and try to fine-tune when you need your power. It may be most cost-effective to run most of your power consuming equipment only during the day and try to coast through the evenings. For winter heating, it might be more cost-effective to keep the unit grid-tied, and heat via solar during the day, but still supplement at least some of the heat at night from the grid.
