Extra batteries and chargers can be found here:
Absima's instruction manual can be found here: (note: big file)
Absima 1/14 ohjekirja
The electronics of the cars are splashproof so a little snow or mud shouldn't be a problem but cleaning the car properly right after is important. Clean the car off with an air compressor or a cloth and spray it down with WD-40 or a similar multifunction oil to leave a light protective layer of oil on the car.