the garage in ohio will be cold in the winter and thus so would the batteries. everybody knows what happens to batteries in extreme cold, but mike is right about the acid and hydrogen being of some concern. get sealed AGM batteries and you don't have to worry. just be sure the charge is set correctly on agms as they don't like to be overcharged and you can't add water to a sealed battery.

Thank you both for those answers. I hadn't thought about the cold in winter effecting the batteries, so I'll keep that in mind. I was concered with having the batteries inside the hope since I have small children, so perhaps an insulated garage would be best.

Any suggestions for the single inverter for the battery bank and grid-tie?

I would say the new Xantrex XW-6048 first choice, outback GTFX3048 next. You also would need a charge controller, so WX-MPPT ( Xantrex ) or Outback MX60

AGM are great and at least here in Lakeland ( where US Battery is based ) they are not that much more than Deep Cycle LA's. I paid 130 each for 220ah/6V AGMS last month

AGM's are a great option! They are not quite as rugged as LA's. LA's perform better, but need more maintenance, if rapid charging, over charging, or deep discharging will occur. The expect life of an LA is better than AGM's, if cared for properly. You need to decide if modestly lower cost for LA's is worth your required efforts to give the expected life rating.

LA's would require spill pans. Hydrogen accumulation is not a major concern, unless in a tight confined space, which is one of hydrogen's problems as an energy source as it can seep through steel. Just the same, there is hydrogen near the vents of a LA battery during charge/discharge.

One way to save a bit on wiring is to go as high of a voltage, lower current for the same power, as possible. Multiple runs of AWG14 or AWG12 are cheaper than anything larger than AWG10 (roughly 1.5xAWG14=AWG12, 1.5xAWG12=AWG10, etc.) Be sure to account for expected losses before choosing conductors! You may, depending on your panel selection, do a run for each panel, which gives many options at the controller end for series/parallel connections.