Hi Herb,
In my application I don't have any concerns since the battery pack is under the bench seat and is effectively in the living compartment and therefore should never be exposed to extreme low temps.
Your correct though if the battery bank was exposed to extreme low temps it would quickly loose it's ability to store power and recharge times would seriously lengthen. Even in the worst case scenario that I can imagine, mine should never see temps lower that 0c and then only briefly. My whole water system would be frozen and I would be headed for home. :sombrero:
Here's a snip from the Sandia Labs testing on this LifeBatt LiFePO4 cell regarding capacity vs temp.
