Last year our cares battery had died after a few days of not being driven. Cold weather and snow being the cause. We replaced the battery. 6 months later its dead again, get it jumped, take it to advanced auto. They swap it out because it had corroded and they felt they had caused it or it might have been defective or improperly installed. So new battery.

Its been about another 6 months. Mom injured herself and couldn't drive for a week. 4 days no start, day 5 started but felt sluggish, 2 days no start, day 8 dead battery. Proceeded to need to be jumped up till Christmas. We disconnected the fuse that ran to the remote starter on Christmas, figured it was draining the battery. Car started and functioned without issue for the remainder of Christmas and 2 full days after. Today, Thursday December 28, car had no power. Jumped the cat and took it to AutoZone, figured it hadn't been fully charged so winter weather or alarm killed the battery. AutoZone tests the battery, its in good condition and fully charged at 100%. So if the battery is fully charged, why did it act like it was stone dead?

The problem: Car has no power, cant start or use any electronic components. Dead battery?
Cause: possibly faulty remote starter, pulled fuse.
Effect: car good for 60 hours.
The second problem: car has no power. Cant start, needed jump
Eliminated theories: Not the battery itself, alternator or starter. remote starter.
Current theories: dying or bad fuse/relay, Corroded connection cables to battery.

The wild card: Now we have no idea if the battery was actually dead, or if there is some kind of connection problem.
The car started at the AutoZone after being turned off. We drove it on city roads for about 15-20 minutes to get to AutoZone. Not long enough to fully charge a dead battery.

The question: was the battery actually dead or just a spotty connection?

Comments and theories highly appreciated, specially if your a car person.

Update: something is draining the battery.