I don't have a blue top, but I have a yellow top deep cycle that started it's life 7 years ago in my S10 pickup. I sold that truck, but kept the battery and put it in my wife's tahoe where it stayed for two years. We sold it and, again, I kept the battery. It has now spent a season and a half as the only battery in our Supra 21V. It stayed in the boat all winter long and was expecting to have to replace it this spring, but it kept its charge and fired up with no problems. Every time I moved it was supposed to be temporary. If your blue tops are anything like my yellow top, it is just getting broken in!
(Message edited by cocheese on June 24, 2009)