battery range /power seems to have decreased

[trex]

I was talking about storing the battery unused for three months. And I'm led to believe that room temperature is not a good idea.

on the contrary. Room temperature keeps your battery dry in winter and right in the middle of optimal condition.
This chart sums up the best operating temperature for your battery:

source: http://www.mpoweruk.com/lithium_failures.htm

 

[flecc]

But that's operating temperature Trex, much cooler is better for long term storage, preferably almost zero degrees C if possible.

However, I accept that just the amount cooler we are usually able to manage doesn't make much difference.
.