Car is dead after getting a new battery

Zipper 104

I'm going to assume it shows it's charging when it's running, but I have no idea if that means only that your alternator is working or the charge is actually getting back into the battery.....so I'd check the first inch or so on the battery cables where they go into the battery connection clamps. Often the first inch or so can get corroded and fail to make decent connections to the battery clamps, and hence the battery terminals. They do a poor job getting a charge back into the battery and often the power back out to the car.
That could explain why an otherwise good battery goes flat in a few days. You're not, or only partially getting a charge back to it. When you jumped it, you were essentially connected right onto the terminals, bypassing the lousy connection(s).
I've had it happen to me. Alternator good, new battery, crappy running car and lousy starts. Two new battery clamps attached to cut back, cleaned up cables fixed all my issues.
Auto Zone probably tested your battery at the battery terminals and tested your alternator at it's outputs. I'm thinking neither test would expose lousy power in and out of your battery. Look at 'em. A real cheap fix if that's what it turns out to be.

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