I was starting to believe that my GPS Li ion batteries were giving up on me after a long cold spell around freezing when I've been using, storing and charging batteries at outdoor temperatures. The result was long charging times and never reaching full charge. However I charged them indoors at around 70F this weekend - textbook full charge in about five hours! Nothing in the manual about this, just the tech spec operating temperature limits of -4F to +131F. So, a bit like my cat the batteries appear to enjoy a warm spell indoors now and again.
You might be interested in this link:
http://batteryuniversity.com/learn/article/charging_at_high_and_low_temperatures
When I was working for a surveying product dealer in a location where temperatures could be below zero in the winter we started putting a label on some chargers telling the user to charge at a warmer temperature because charging some types of batteries in what I'll call a basic charger could short out the charger. More sophisticated chargers and some batteries have temperature sensors.
My last chemistry class was too long ago for me to remember much but temperature can affect chemical reactions which is what charging a battery really is.
Artie,
This is a link to a white paper for Leica batteries....
The information about th different types of battery cells, needed charging temps, etc. apply accross the board regardless of the manufacturer.