Today was the first, real, Official full time EV use to work and back. I was welcomed on this September first with 48 F weather! It was in the 90s last week, and all of a sudden it was cold and brisk. On the way in, I did notice the cold had an effect on the batteries, and I messed with the charger yesterday didn't help.
First, the charger. I was reading that I should set the float on my charger to 14.4 volts, so I did. Well, some batteries didn't get fully charged because of that, so it went right back to 14.8 volts this morning when I got it.
Now the temp. According to this: http://www.windsun.com/Batteries/Battery_FAQ.htm#Temperature%20Effects%20on%20Batteries the batteries were down to about 87% capacity due to the weather, and that was dead on. I usually have 40-50% left, but I was closer to 25% left and did my best to slow down. I did a few trial last winter and found that betteries were much warmer when left charging over night and range was quite decent compared to cold batteries, so tomorrow I will get to see if it still true since I will have the EV charger most of the night.
It's time to start thinking about installing the ceramic heater and get down to insulating the batteries, for real this time. I am looking into sheet metal or some type of cheap plastic to house the foam insulation.