Defective alternator, dead cell in battery, stuck relay, or something is on pulling power from the battery. Any light that is on such as under-hood, trunk, glove box, dome, etc.
Either something is draining the power - or the battery is at the end of its useful life.
Something is usually on that you don't know about like an alarm could be draining the battery. However, If its not starting you should check the starter though. It will make you think the battery is bone dead.
Then either something is on draining the battery or the battery has a dead cell draining all the rest and must be replaced.
A short will not drain the battery it will blow a fuse. It may be the battery has a dead cell, or some light is on draining the battery. It can also be a stuck relay.
Either the battery has a dead cell which will drain the other cells, or something is on and draining the battery. Possibly trunk, glove box, or under hood light. Have the battery tested for a dead cell.
Something is on draining your battery overnight. Any light or any relay. It can also be your battery has a dead cell draining it overnight.
There is a circuit live somewhere.
you possibly have something draining the battery when the car is shut off, with the car shut off pull the positive cable off the battery and then just touch the cable to the positive post of the battery and see if you get a spark, if you get a spark you have something electrical draining the battery.
Had the same problem. Bought a re-conditioned alternator, turned out it was bad. Usually if battery draining, it's alternator or battery or both.
Are the battery wires corroded? If they are, they may not be getting a good connection.
If the ignition isn't firing then you're looking at an electrical problem: Bad spark plugs, distributor, cables or battery. If you're frequently draining your battery and needing jump starts, the alternator could be failing as well.
Either the battery has a dead cell and needs replacing, or alternator is defective, loose or corroded battery cables, or something is draining the battery. Look for a courtesy, trunk, under hood, glove box light that is on. Also can be a defective brake light switch which causes the brake lights to stay on.