That's pretty similar to what I wear for winter commuting. I've found that urban/skate-style helmets are much warmer than conventional MTB/road helmets. Nutcase offers add-on ear covers, and they make a noticeable improvement.
I live in Colorado and a good portion of my riding takes place in sub-freezing temperatures. Based on my entirely non-scientific observations, cold weather doesn't seem to impact battery life/usage.