Bakcou solved the problem for those wanting to ride their eBikes when temperatures drop with the Thermal Electric Bike Battery Jacket.  Unfortunately, those cold temperatures cause a drop in battery efficiency. 
 
Ebike batteries should maintain a core temperature of 50-75 degrees fahrenheit for optimal performance. First and foremost, the Bakcou Thermal Battery Jacket helps control the temperature of your battery. Additionally, the Thermal Battery Jacket, constructed of a water repelling fabric, protects your battery from the elements.
 
The Thermal Electric Bike Battery Jacket wraps around your Bakcou eBike battery to maintain the temperature of the individual lithium ion cells. This is especially important for those cold days/nights on the mountain or in the field. The heating element is intended for warming the battery and should NOT be used while riding except during those first few minutes while you help the battery reach an optimal operating temperature.
 
If temperatures drop below 40°F, utilize the Bakcou Thermal Electric Bike Battery Jacket. Alternatively, once those temperatures rise above 40°F, remove it. On icy cold days in the field, keep the Battery Jacket on your bike with the heating element on low.