I took that battery back to Costco and got an almost-free replacement. (don't remember after almost 2 years if I said that) The replacement battery lasted 22 months and then it crapped out. If I go 2 or 3 days w/o driving and the weather is kinda cold, or if the weather is just really cold it won't start. Turn the key and the starter engages but it runs out of juice in about half a second and the motor doesn't start quite that fast. I hooked the fancy battery charger up to it and it refused to charge because it said the battery is full. I put a non-computerized Harbor Freight trickle charger on, and an hour later I can start it. I checked my alternator with the previously mentioned fancy charger and it's fine.
I took the car to Autozone and they checked the charging system and said it's okay. They tried to load-test the battery and their load tester refused to run. So they told it it was a 500 amp battery instead of 590, then load tester did its thing and said just over 50% capacity.
Took the battery back to Costco and the paperwork was a bit much because they couldn't find my purchase in the computer (my membership number had changed) but I had the paper receipt and they gave me a new battery for $8 and change.
I don't like this pattern.