how can I tell if u need battery or alternator?
I just bought the car a few days ago and it was
acting like it didn't want to crank if it sat too long
and I can't get it to crank today I don't know if it's
battery or alternator?
Use a voltage tester. With the engine running you should see about 13.5 to 14.5 volts across the battery terminals for a good alternator. With the engine off you should see about 12.5 volts at the battery if if is good.