Cold Weather Charging

From the Forum, Brian Wismann provided this information about cold weather charging:

"[T]he issue with cold weather (sub-freezing) charging is metallic lithium plating in the actual cell. This can cause permanent degradation to your batteries, and it's best to avoid if at all possible. You can read more about it here:

Link to Battery University website.

One thing to remember is that what we're really concerned about is the temperature of the battery and less so the ambient tempertaure. If you've just completed a ride at 32F, it's unlikely that your batteries are also at 32F as discharging requires current and current generates heat (especially with increased impedance due to the cold temperatures). Given the thermal mass of the batteries, they'll also stay warm for a considerable amount of time following the ride. So... worst case scenario and to be avoided is charging the bike outdoors in sub-zero temperatures after the bike has been sitting in that environment for serveral hours."