LANCER wrote on 12/31/69 at 16:00:01:I am not familiar with the Big Crank, but the Odyssey being a "DRY CELL" battery made a big difference to me. It can be mounted up, sideways, or upside-down for that matter. There is nothing to spill, ever. Nothing to add, ever.
I bought mine 2 years ago for $68 flat price in an ebay store.
Both are AGM (absorbed glass mat) and should be similar in many ways, though some recommend against upside-down mounting. I am very happy with my Odyssey though, I must say. Here's a
deep cycle battery FAQ I found to be pretty good.