I use the Battery Tender Jr. for $35. Works great. Kept my stock battery working fine (6.5 years) until I drained it last week sitting at the Canadian border with the key on. Battery might have been okay still but I was in the middle of a trip and didn't risk getting stranded somewhere less ...populated. The BT should keep the new battery going for much longer than 6.5 years (I only used it on my old battery for the last two winters).
