Howdy Big5er, Sorry it's been so long since I have corresponded with you I have forgotten your real name, I think it's "Phil" but I don't know for sure.
Thanks for the link, that looks like a real good idea as the car sits on the deck of the truck for months without being started or used. You say you just leave it plugged in all the time, without some sort of monitor isn't there a chance of over charging the battery?
since I have a company truck, I rarely drive my smart. I got tired of jump starting and ruining batteries.
I hardwired a cigarette lighter plug straight to the battery and bought a small solar charger that I throw between the windshield and the sun screen. It just back-feeds through the cigarette lighter plug. I leave it on all the time the car is parked, even on the trucks deck.
I got something like this. Amazon.com: Topsolar 20 Watt 12 Volt Solar Trickle Charger 20W 12V Solar Panel Car Battery Charger Portable Solar Battery Maintainer for Car Motorcycle Boat Marine RV + Cigarette Lighter Plug Alligator Clip : Patio, Lawn & Garden