Seth, we've talked about the Festool lithium batteries numerous times already but maybe you were on the throne the last two or three times that has happened. [tongue] They don't like the cold all that much. Keeping them in the truck overnight in the cold will likely leave you disappointed in the morning. They'll warm up fairly quickly on the charger. Once they're warm again they work fine, just don't let them sit idle in the cold for too long.
Ken Nagrod said:
Seth,
As my friend from Makita once told me in the dead of summer, no problem testing the batteries in the cold. Just stick them in the freezer or refrigerator for a while and pull them out for testing their cold performance. Either that or grab a coat and hat and find a meat locker. [wink]
I wouldn't put the batteries in the freezer for too long, remember most freezers are set to zero degrees Fahrenheit. That's unnecessarily cruel to the battery.