So I put a new battery in my car because I thought the other was no good. The problem is, after the car sits a day or two, the battery will completely drain. Any ideas on what could be draining it? Theres no interior lights on or anything like that.

 

Youre positive that none of the center console or rear hatch lights are on? Thos ewouldnt be obvious but tend to drain a battery real quick. If its none of them, alternators have occasionally had internal problems where they still charge while running, but drain the battery when the car is off. If you have a digital multimeter, the best bet is to test for draw off the battery while pulling fuses/removing circuits until that draw goes away...then you at leats have your circuit narrowed down.

 

ive searched everylight in it and nothing is on. the digital multimeter would be a good idea but i dont have one.

 

Well, without a meter, it will be hard to really hone in on the problem if it isnt as simple as a light or alternator issue. Sometimes the ecm if something happened with it will draw too much as well. All these are speculation and without a tool to test, youll just be throwing money at the problem without a good reason or direction. Id invest in at least a cheap multimeter...doesnt have to be a snap-on or anything, just something cheap to read amperage draw.

 

Could also just use a light bulb between the battery cable and the terminal.
Obviously don't try to start the car with it that way. Just keep pulling fuses until the light goes off.