The most CCA's in the smallest, lightest package that you can find.
How many amps is the alternator?
I've seen some of you Cali guys posting about 60° weather already!!! We are still in the single digits and not getting up to freezing yet. We had a "warm spell" in the low 40's a week and a half ago. We were driving around without jackets and the car window halfway down!! Canada is much colder than we are - Shout-out to the Canadians --->>> eh... LOL!
I prefer the most CCA's in the larger stock size battery. The bigger the battery, the more "reserve" it will have (be able to crank a dead car longer than the smaller batteries).
You can get some DieHard gold batteries with up to 800 CCA. At freezing (32° F or 0°C), the battery only has half of its rated CCA. As it gets colder it looses more CCA's. .
Once you get in the single digit °F to the minus teens °F, you turn the key and nothing happens... You think or say out loud, "Cmon baby, start..." Then it starts to crank, and you hear the starter groaning and complaining struggling to turn the engine over slowly. Then she finally fires after cranking longer than usual, and you hear the pulleys and belts squeaking from the cold until they heat up from friction and get a little more clearances and finally quiet down. You feel how stiff everything is for the first ten minutes that you drive.
I used to work at a Sears garage back after high school. They had the mini "Incredicell" battery rated at 650 CCA. The top of the line full size DieHard was rated at 550 CCA. They told us mechanics to test the Incredicell at only 550 amps not 650 on the load tester.
This sparked my curiosity. So I went into the stock room one day and got one of each brand new off of the shelf. Then load tested them at 550 amps, and then 650 amps. The larger 550 CCA battery out tested the little 650 CCA battery and could hold a load much longer than the little Incredicell.
If they get that much power out of a smaller battery, why couldn't they get more out of a full size one using the same technology? More volume = more capacity to store charge. Just like "there's no replacement for displacement"...
And like Rodney Dangerfield used to say:
How many times on a cold, cold morning.... When you really need it... A car and a woman, they won't turn over....