Interesting, if complex...why not just attach a Batt Tender, maybe connected through a simple mechanical appliance timer, to come on for ~24 hrs a couple times a week?

I do that to one of the cars I leave for 5 months each winter.
GL, mD

__________________
Ol'UncleMotor
From the Home Base of Pro Bono Punditry
and 50 Cent Opins...

Our Mtn Scenes, Car Pics, and Road Trip Pics on Flickr:
http://www.flickr.com/photos/4527537...7627297418250/
http://www.flickr.com/photos/4527537...7627332480833/

http://www.flickr.com/photos/45275375@N00/

My X Page