We added a 2013 Wheego LiFe to our fleet. It didn’t come with a cold weather package and I was worried about charging the battery pack when the temperature was below freezing. Here is the DIY solution we created to protect the battery in winter.
Take one panel of Owens Corning closed sell rigid insulation foam board and cut it to the size of the bottom of the car’s battery box. Dig out any channels necessary for it to fit tight against the box, as well as a channel for an electric cord. Place an electric under-floor radiant heating mat in the center of the foam. Fiberglass the mat to the side with the channels. Fiberglass the opposite side as well (for strength). Add metal hooks to attach the heater to the underneath of the car. A brief video introduction of the project can be found on our Facebook page.
The resulting heater is light, though big. When the car is parked, the heater can be attached to the car. The insulation helps keep the battery box warm and the radiant heat helps keep it above freezing. The down side of this solution is that the heat mat does not quickly warm a cold battery box to above freezing. This is a solution that is good for when the car is to be stored in the garage over the course of a few days.