The house battery as as been discussed before has different operating
parameters than the starting battery.  CCA is a measure of how much
current can be delivered for a short period of time (no pun intended).
 A house battery does better if it is  designed to deliver smaller
currents (<30A) over a longer period of time.

The starting battery has porous plates so the maximum electrolyte to
plate contact is available for high current applications.   The plate
surface per cell dictates how fast the electrochemical reaction can
proceed.  The more contact the faster it goes and the more current
that can be drawn.  However this configuration of plates is not well
suited to small <30 current draw over longer periods of time.  For
that application a solid plate is best.  Batteries that have these
sorts of plates don't deliver much in the way of CCA but do have a
larger reserve capacity measured usually in Ampere Hours. They're more
resilient and longer lasting than a starting battery of the same
physical size used as a deep discharge current source.  More charge
discharge cycles without damage.

On 6/20/08, Troy <colorworks@gci.net> wrote:
> Here's a link to various group sizes of batteries and thei r demensions. FWIW, the 40R, (not mentioned) has one of the highest AH ratings of them all, with lots of room to spare. Sears also has a 5 yr warranty, no questions asked for the 1st 3, then prorated thereafter. Don't forget to cover the underside of the cover (or battery terminals) with non conductive material!
>
>
> http://www.batteryweb.com/bci.cfm.
>
> Troy
>