My car cranks but in order to start you need to crank for a long while, and also after it starts is turns off, and the battery dies super quickly. Is is a fuel or electrical prob?
Not much to go on here but I would suspect a fuel delivery problem of some sort.If it is an older car with a mechanical fuel pump the pump may be getting weak. If it is carburated the accelerator pump may be worn out. Try pumping the gas pedal vigorously before and as you are starting the car. If this helps I would service the carb. Of course if it is a newer car none or this applies. Make sure the battery terminals are clean and tight. They are still going to heat up some from the extended cranking though and if the battery dies quickly it is likely near the end of its life and will need replacing soon. However that is not likely the source of your problem.