Here in NJ, they go overboard on the road salt before, during and after snow fall. So I have to keep an eye on snow melt, as it can do a number on your bike's components if you don't get it off after each ride.
From homebase, it takes me 6 miles of road riding to get to the canal towpath trails. During times of snow fall, I will not put my life in the hands of others slipping and sliding on the roadways next to me as I pedal on the little bit of roadway shoulder that the county has paved in. Instead, I'll await the snow melt and clean roads before I go out.
Dressed warm, in layers of poly-propylene clothing is the trick. Folks miss out on a terrific time of year by not pedaling in the winter. But each person reacts to cold different then the next. For myself anything in the 20's and colder is pushing the limits, especially in the shorter hours of daylight. When it gets that cold and bitter, it pays to have an exit plan to safety, especially if you consider breaking down (ie, flat tire) when you are the furthest point away from your home starting point.
Yesterday we were 2 days removed from the super bitter cold blast from the midwest. I wanted to get out in order to take some pictures of the frozen Delaware River before the last of what I believe to be the ice of winter 2018/19 is gone. Here are some pics of yesterday's ride, and the frozen Delaware at Trenton, NJ....
Regards to battery charging, etc: My Haibike Full FatSix features the Yamaha PW drive system. In a bit over 6000 miles of riding, I simply plug in the charger and let it go until the built in bms system shuts it off when it reaches full charge. Before setting off on a ride, I'll unplug the charger, plug it back in and if the bms senses lower than normal voltage, it will top it off to full. Then, I set off on my ride.
I cannot speak for other ebike charging and battery systems. The Yamaha is really a "set it and forget it" set up. I will assume Bosch is the same way.