You need to check the starting circuit. The starter can be dragging and causing excessive amperage draw. You could have dirty connections on the battery, solenoid, or starter reducing the voltage to the starter. The battery could be weak. Batteries aren't as efficient in cold weather, so that could be an issue. A good automotive electrical shop can check the amp draw of the starter. If the voltage to the starter is good and the starter checks out, it's a problem with the engine. You might need a lighter weight engine oil if you're operating in cold weather.
