A new battery doesn't mean a good battery, sometimes they are just faulty. Rare I know but might be worth getting that checked out just to be absolutely sure. Now, assuming it is a good battery it may be losing its charge due to an electrical (or parasitic) draw. This means that something is drawing the power, even with the key off and the car locked up and parked for the night. Is an internal light left on? Some are under the hood, in the trunk, in compartments inside the vehicle, behind sun visors etc. Alarms are a common problem. The only way to properly check is to check the power in the battery with a digital meter and pull fuses to find which circuit is at fault. Below is a good youtube video to explain it. https://www.youtube.com/watch?v=KF1gijj03_0
Check that battery cables are secure on both ends of both cables. Check the alternator cables for abnormal wear, including cracking and fraying. Replace or tighten the cables as necessary.
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A new battery doesn't mean a good battery, sometimes they are just faulty. Rare I know but might be worth getting that checked out just to be absolutely sure.
Now, assuming it is a good battery it may be losing its charge due to an electrical (or parasitic) draw. This means that something is drawing the power, even with the key off and the car locked up and parked for the night. Is an internal light left on? Some are under the hood, in the trunk, in compartments inside the vehicle, behind sun visors etc. Alarms are a common problem.
The only way to properly check is to check the power in the battery with a digital meter and pull fuses to find which circuit is at fault.
Below is a good youtube video to explain it.
https://www.youtube.com/watch?v=KF1gijj03_0
Check that battery cables are secure on both ends of both cables.
Check the alternator cables for abnormal wear, including cracking and fraying. Replace or tighten the cables as necessary.