Check your battery cables.
Try to move them by hand from side to side. If they move when you push they need to be tightened. Before tightening cables, remove them from the battery and be sure to clean the connections with a cleaning kit. Any auto parts store will carry battery cleaning kits. Never work on or remove battery cables with your key in the car’s ignition. This can cause an arc of power that can do harm to your car electronics. If you need to clean your battery connections and you don’t have a kit, you can use a tablespoon of baking soda with about a 1/3 cup of water to remove corrosion. Also any cola type product will clean the connections well enough to get you going for a few days.
If you do not keep your battery fully charged and properly maintained you can not only do harm to your car but you may find your self stranded in need of a tow truck.