Thanks for help everyone. My question was answered - plus I learned much more than expected. My trailer is typically stored at my home and used for one 2-3 week trip per year plus weekend trips. From May to September I will leave the batteries in the RV with the RV plugged in at home. From October to April I will remove the batteries and store them in my garage. I will make sure that they are charged prior to storing and will then hook them up to this unit for longer term winter storage:
http://tecmate.com/products/optimate5v/
Thanks again.