Before you go spend any money on any parts. Please do as some of the others have suggested and clean your negative battery cable clamp and post with a wire brush. I have seen this happen multiple time on various cars I have owned and worked on. An invisible layer of corrosion forms on the surface of the clamping area. This layer blocks most of the current. For some reason this phenomenon usually occurs out of the blue, in cold damp weather. Like after a snow storm or after some rainy foggy days. Don't just rely on looking at the clamps. You must remove and physically clean them. Give it a try . I think you will be happily surprised. Good luck!