The angle of the sun during the winter is different than during the summer. Because the sun is lower during the winter than in the summer.
Solar pannel produce less electricity as compaire to summers, As a result, you may either need to reduce your energy usage.
Batteries aren't meant to work in very low temperatures. If you keep your batteries outdoors, monitor the temperature to ensure it's in the optimal range.
Don't completely discharge your solar batteries, some batteries may be suited for discharge levels of 70% to 80%, the recommended discharge level is actually 50%.
Snowfall block the sunlight from reaching to pannel so clean it regularly.