many things can do it suck as junk battery, junk alternator , or leaving anything on in the car
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.
Assuming the battery is good, you have a short somewhere in the electrical system that is draining your battery. You can confirm this by disconnecting the battery each time it is parked. If that solves problem, a short is confirmed. A professional has the devices to locate the site of the short.
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.
Are the battery wires corroded? If they are, they may not be getting a good connection.
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.
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.
2004 Chevy express van, heater has no high speed, at one time the blower stayed on even when the ignoton was turned off therefor draining the battery,
A partial earth
Something is on draining the battery or it has a dead cell and needs replacing.
Hold the gas pedal in, and slowly let it out. Will it eventually idle? Common after draining battery, check proper IAC operation.