Got my daughter this car in May and it drove well when driven everyday. She leaves it home and goes to school and the car won’t start if not driven for 5 days or so. Put in new battery, had it checked for drain, nothing left on and no out of market radio or speakers. What could cause a new battery to drain like this?
Does this car have automatic headlights? Does it have a key pad on the door? Try turning he headlights to the “really off” position if it has auto lights.
Anything over a 50 milliamp draw can drain the battery. You’ll need a digital multimeter with amps on it to test for the draw. Leave the driver door open, remove key from ignition, disconnect negative battery cable. Use a heavy jumper wire from negative battery post to negative cable. Next, setup meter for amps and hook one end to negative post, other end to cable. Just like you did with the jumper wire. Leave jumper wire and tester wires connected for 30 minutes. This will let modules go to “sleep”. After 30 minutes remove jumper, leaving meter connected. Now you can see how much of a draw there is. Remember you left the door open so now you can start pulling fuses one by one until you find the circuit causing the draw. Remember don’t replace a fuse you pulled until you’re done testing, otherwise you might “wake up” a module.
Many Many things can do this. If you are proficient with cars and have some basic tools you can try this. You need a 12V type Multimeter/Voltmeter.
Remove the negative terminal of the batt. put the voltmeter in between the batt post and the neg batt cable. Set your multimeter to Ohms and then notice the level of current draw in Ohms. Then begin to remove fuses one by one when you notice the voltmeter ohm draw jump…you just found the “Vampire Circuit” that is sucking the life out of your battery. Then yo can go deeper into what in that circuit is the culprit…this task is of a moderate level to perform. Go slowly and use your head. This is the precise process that any mechanic will use to diagnose your issue…IF they knew what they were doing.
Many many many times the alternator is the cause of the issue.