Mnfish,
Forgive me if you posted it already but:
1. Does your stand alone system run 24/7?
2. Are you using a 12 volt compressor or an AC model?
In my reading of the book it appears if I want to run my 60 watt AC linear air pump for my aquaponics system the capital investment isn't cheap with solar panels and batteries. If I use a 12 volt compressor it's still a lot cheaper over the short run to use an AC compressor and power it off the grid.
Now 12 volt and only running when the solar power is available is another story. However that is not an option with my aquaponics system.
Another option that would simplify things for me close to the house would be a grid fallback system not to be confused with a grid tie system. I would use power produced via solar and stored in batteries, and when that is almost used up the circuit picks up the slack from the grid. Then when there is sufficient juice from the solar array to power the compresser again it automatically switches back. Still not convinced of the cost effectiveness vs. straight grid.
Last edited by Cecil Baird1; 11/08/14 10:03 AM.
