Quote Originally Posted by kpaske
The Optima Blue Top means it's a marine battery. They are not all the same. There are several models that are deep cycle (like the yellow top), but also a starting battery (like the red top). I have been running the blue top starting battery (model 34M) in my VX for a few years now. (http://www.1st-optima-batteries.com/...op_battery.asp )

When I originally did my research, I concluded that the blue top starting battery was nearly identical to the red top starting battery. In practice, it has behaved exactly as any other starting battery.

I did have to have it replaced once, under warranty. After sitting for about a month, it was completely dead and would not take a charge. The store I bought it from exchanged it for a new one and I haven't had any problems in nearly a year and a half. I've heard some reports of "quality control problems" with Optima, but from my experience, they are great batteries. For the past several months, my VX has mostly sat, only being driven once a week. I do have a solar trickle charger on it now, because my aftermarket alarm system draws a little bit of power, and over time i think that contributes to battery drain. But now it starts up strong every single time.
this is the link I meant
http://www.1st-optima-batteries.com/faq18.asp
The blue and yellow top are the same, except blue has extra terminals

From the link
"The D31-series batteries are the largest made by Optima. The only differences are in the type of electrical connections and the color. There is no difference in the internal construction or performance of these three batteries; they are electrically identical. "