If you will read my previous post about the 750cca v/s 850cca-my local battery distributor told me that they have had considerable trouble with the 850cca in that IT has more plates than the 750cca IN THE SAME CASE, and my guy says there IS NOT enough room then in the 850cca for the electrolite to do its job efficiently-HE was telling me that the 850s were more expensive and he would rather not sell me one, he says hes heard this from the manufacturer...........Plus I think I'll keep the "blankie" on my passenger side batt too!