Can't say enough about the battery tenders... Just check the water level of the battery, hook up the tender, and forget about it till spring. It takes great care of your batteries and will prolong their life.
I have a tender for each battery I own, and for the smaller ones like lawn tractor, quad, etc. you can get a tender junior which will save you a bit of money. The juniors put out 0.75A and the regular is 1.25A.